explanation blue bibcodes open ADS page with paths to full text
Author name code: bentley
ADS astronomy entries on 2022-09-14
author:"Bentley, Robert D."
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Title: Constraining the Binarity of the S-stars Orbiting the Central
Supermassive Black Hole Using Radial Velocities
Authors: Chu, D. S.; Do, T.; Ghez, A.; Hees, A.; Ciurlo, A.; Gautam,
A.; O'neil, K. K.; Hosek, M. W., Jr.; Chen, Z.; Sakai, S.; Lu, J. R.;
Bentley, R.
2021ASPC..528..321C Altcode:
The formation mechanism of the young S-stars located within an arcsecond
of the central supermassive black hole remains a mystery. While binaries
are important for understanding the young star cluster at the Galactic
Center, there have been limited surveys for binaries in the region. We
present a framework for searching for spectroscopic binaries. With over
two decades of integral field spectroscopy data and advanced tools
for fitting mid-infrared stellar spectra, it is feasible to conduct
a spectroscopic binary search of the Galactic Center S-stars. After
subtracting a star's motion around the supermassive black hole, we
search for a periodic signal using a Lomb-Scargle analysis and fitting
the residual radial velocity curve to a binary system radial velocity
curve. We find no significant periodic detections in our sample,
suggesting there are no binaries among the S-stars. These results favor
formation mechanisms that result in the S-stars being single stars.
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Title: Search for a variation of the fine-structure constant around
the supermassive Black Hole in our Galactic Center
Authors: Roberts, Benjamin; Hees, A.; Do, T.; Ghez, A. M.; Nishiyama,
S.; Bentley, R.; Gautam, A. K.; Jia, S.; Kara, T.; Lu, J. R.; Saida,
H.; Sakai, S.; Takahashi, M.; Takamori, Y.
2020APS..DMPE01155R Altcode:
Searching for space-time variations of the constants of Nature is a
promising way to search for new physics beyond General Relativity and
the standard model motivated by unification theories and models of dark
matter and dark energy. We propose a new way to search for a variation
of the fine-structure constant using measurements of late-type evolved
giant stars from the S-star cluster orbiting the supermassive black hole
in our Galactic Center. A measurement of the difference between distinct
absorption lines (with different sensitivity to the fine structure
constant) from a star leads to a direct estimate of a variation of the
fine structure constant between the star's location and Earth. Using
spectroscopic measurements of 5 stars, we obtain a constraint on the
relative variation of the fine structure constant below 1e-5. This is
the first time a varying constant of Nature is searched for around a
black hole and in a high gravitational potential. This analysis shows
new ways the monitoring of stars in the Galactic Center can be used
to probe fundamental physics.
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Title: Solar Windsocks - A service to derive estimates of solar wind
speeds from comets' ion tails
Authors: Jones, Geraint; Bentley, Robert; Ramanjooloo, Yudish
2018cosp...42E1635J Altcode:
Comets' ion tails show material being carried away from cometary
nuclei by the solar wind. As we know where each comet is, how fast it's
moving, and in what direction, we can use the orientation of the tail to
estimate the solar wind speed at the comet. Solar Windsocks is based on
the assumption that the solar wind flow is radial, i.e. that it flows
directly away from the Sun. This is known to not quite be true, with
the solar wind often deviating a few degrees from the radial direction,
but this assumption is necessary in order to derive solar wind speed
estimates from comet images. The service takes a user's image, and
projects it onto the comet's orbital plane. The position of the ion
tail is then identified manually in the image, and the solar wind speed
corresponding to each marked position in the tail is calculated. Using
this technique, several solar wind speed estimates can be provided from
each image. It is hoped that amateur and professional comet observers
will donate their images and the resultant solar wind speed estimates to
the project, to build up a database of point measurements of the flow
speed in the inner heliosphere. The Solar Windsocks project is only
possible through the financial support of the Europlanet-2020 Research
Infrastructure, funded by the European Commission. Solar Windsocks is
part of the Europlanet Planetary and Space Weather Services activity.
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Title: The Economic Impact of Space Weather: Where Do We Stand?
Authors: Eastwood, J. P.; Biffis, E.; Hapgood, M. A.; Green, L.;
Bisi, M. M.; Bentley, R. D.; Wicks, R.; McKinnell, L. A.; Gibbs, M.;
Burnett, C.
2017RiskA..37..206E Altcode:
Space weather describes the way in which the Sun, and conditions in
space more generally, impact human activity and technology both in
space and on the ground. It is now well understood that space weather
represents a significant threat to infrastructure resilience, and is
a source of risk that is wide-ranging in its impact and the pathways
by which this impact may occur. Although space weather is growing
rapidly as a field, work rigorously assessing the overall economic
cost of space weather appears to be in its infancy. Here, we provide
an initial literature review to gather and assess the quality of any
published assessments of space weather impacts and socioeconomic
studies. Generally speaking, there is a good volume of scientific
peer-reviewed literature detailing the likelihood and statistics
of different types of space weather phenomena. These phenomena all
typically exhibit "power-law" behavior in their severity. The literature
on documented impacts is not as extensive, with many case studies,
but few statistical studies. The literature on the economic impacts of
space weather is rather sparse and not as well developed when compared
to the other sections, most probably due to the somewhat limited data
that are available from end-users. The major risk is attached to power
distribution systems and there is disagreement as to the severity
of the technological footprint. This strongly controls the economic
impact. Consequently, urgent work is required to better quantify the
risk of future space weather events.
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Title: The Heliophysics Feature Catalogue, a tool for the study of
solar features
Authors: Bonnin, Xavier; Fuller, Nicolas; Renié, Christian;
Aboudarham, Jean; Cecconi, Baptiste; Bentley, Robert D.; Csillaghy,
André
2014IAUS..300..512B Altcode:
The behavior of filaments and prominences during the Solar Cycle is
a signature of Sun's activity. It is therefore important to follow
their evolution during the cycle, in order to be able to associate it
with the various phases of the Solar Cycle as well as with other Solar
features or events. The virtual observatory HELIO provides information
that can be used for such studies, especially its Heliophysics Feature
Catalogue gives a unique access to the description of various features
during around one cycle. Features available are: filaments, prominences,
photospheric and coronal active regions, coronal radio emission, type
III radio bursts, coronal holes and sunspots. Web interfaces allow the
user to query data for these features. Useful information can also be
shared with other HELIO services, such as Heliophysics Event Catalogue,
which provides access to dozens of tables of events such as flares,
CMEs, . . .
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Title: HELIO - Discovering solar effects in all the heliosphere
Authors: Pérez-Suárez, D.; Bentley, R. D.; Aboudarham, J.; Brooke,
J.; Csillaghy, A.; Gallagher, P. T.; Jacquey, C.; Messerotti, M.;
Pierantoni, G.
2013EPSC....8..328P Altcode:
HELIO, the HELiophysics Integrated Observatory, consists of a set of
integrated software tools developed by an international consortium under
the European Commission's Seventh Framework Programme (FP7). HELIO
is designed to help scientists easily search heliophysical data
and discover any possible connections. This is achieved by merging
information from feature and event catalogues and services that know
about the locations and capabilities of instruments to find all the data
available that contain information on a certain event by propagating
it through the whole solar system. There are then tools to access data
archives and processing tools that allow the users to create their own
workflows. <P />HELIO is definitely making the research in heliophysics
more accessible to different scientists [1] but it capabilities goes
further than this. It can be adapted to other fields in science,
where multiple observations in different observatories are used to
study a particular event. The interfaces of the HELIO services are
based onWeb services and, as far as possible, are compliant with IVOA
standards. This simplifies access to the capabilities via different
tools like Web browsers, scripting languages (IDL, Python, etc.), and
workflow tools (Taverna, Kepler, etc.). The overall capabilities of
the system can greatly increased when the services are combined using
workflows or scripting languages. While we try to hide the use of these
tools for most users, those who choose to gain familiarity with such
tools can address more complex problems. <P />A brief introduction to
HELIO services and a use case demonstration will be presented.
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Title: SHEBA - HELIO's propagation model: a walk through its
possibilities
Authors: Pérez-Suárez, David; Pierantoni, Gabriele; Maloney, Shane
A.; Higgins, Paul A.; Gallagher, Peter T.; Bentley, Robert D.
2013EGUGA..1513919P Altcode:
The Heliophysics Integrated Observatory (HELIO) is a software
infrastructure involving a collection of web services, heliospheric data
sources (e.g., solar, planetary, etc.), and event catalogues - all of
which are accessible through a unified front end. HELIO brings to the
scientist the possibility to search an event occurred in the heliosphere
and find out which other events are linked with the one under study. To
get the relation between events HELIO uses SHEBA (Solar-Heliospheric
Event Ballistic Algorithm), a simple propagation model for Coronal
Mass Ejections, Solar Energetic Particle and Co-rotating Interaction
Regions. This poster explains the basics of SHEBA and it walks through
real-case scenarios of its use.
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Title: Automation of the Filament Tracking in the Framework of the
HELIO Project
Authors: Bonnin, X.; Aboudarham, J.; Fuller, N.; Csillaghy, A.;
Bentley, R.
2013SoPh..283...49B Altcode: 2012arXiv1202.2072B; 2012SoPh..tmp..132B; 2012SoPh..tmp..103B
We present a new method to automatically track filaments over the solar
disk. The filaments are first detected on Meudon Spectroheliograph
Hα images of the Sun, applying the technique developed by Fuller,
Aboudarham, and Bentley (Solar Phys. 227, 61, 2005). This technique
combines cleaning processes, image segmentation based on region growing,
and morphological parameter extraction, including the determination of
filament skeletons. The coordinates of the skeleton pixels, given in a
heliocentric system, are then converted to a more appropriate reference
frame that follows the rotation of the Sun surface. In such a frame,
a co-rotating filament is always located around the same position, and
its skeletons (extracted from each image) are thus spatially close,
forming a group of adjacent features. In a third step, the shape of
each skeleton is compared with its neighbours using a curve-matching
algorithm. This step will permit us to define the probability [P]
that two close filaments in the co-rotating frame are actually the
same one observed on two different images. At the end, the pairs of
features, for which the corresponding probability is greater than
a threshold value, are associated using tracking identification
indices. On a representative sample of filaments, the good agreement
between automated and manual tracking confirms the reliability of the
technique to be applied on large data sets. This code is already used
in the framework of the Heliophysics Integrated Observatory (HELIO)
to populate a catalogue dedicated to solar and heliospheric features
(HFC). An extension of this method to other filament observations,
and possibly sunspots, faculae, and coronal-holes tracking, can also
be envisaged.
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Title: The Philosophy of User Interfaces in HELIO and the Importance
of CASSIS
Authors: Bonnin, X.; Aboudarham, J.; Renié, C.; Csillaghy, A.;
Messerotti, M.; Bentley, R. D.
2012ASPC..461..303B Altcode: 2012adass..21..303B
HELIO is a European project funded under FP7 (Project No. 238969). One
of its goals as a Heliospheric Virtual Observatory is to provide an easy
access to many datasets scattered all over the world, in the fields
of Solar physics, Heliophysics, and Planetary magnetospheres. The
efficiency of such a tool is very much related to the quality of the
user interface. HELIO infrastructure is based on a Service Oriented
Architecture (SOA), regrouping a network of standalone components,
which allows four main types of interfaces: - HELIO Front End
(HFE) is a browser-based user interface, which offers a centralized
access to the HELIO main functionalities. Especially, it provides
the possibility to reach data directly, or to refine selection by
determination of observing characteristics, such as which instrument
was observing at that time, which instrument was at this location,
etc. - Many services/components provide their own standalone graphical
user interface. While one can directly access individually each
of these interfaces, they can also be connected together. - Most
services also provide direct access for any tools through a public
interface. A small java library, called Java API, simplifies this
access by providing client stubs for services and shields the user
from security, discovery and failover issues. - Workflows capabilities
are available in HELIO, allowing complex combination of queries over
several services. We want the user to be able to navigate easily,
at his needs, through the various interfaces, and possibly use a
specific one in order to make much-dedicated queries. We will also
emphasize the importance of the CASSIS project (Coordination Action
for the integration of Solar System Infrastructure and Science) in
encouraging the interoperability necessary to undertake scientific
studies that span disciplinary boundaries. If related projects follow
the guidelines being developed by CASSIS then using external resources
with HELIO will be greatly simplified.
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Title: Combining observations to study heliospheric phenomena
Authors: Bentley, R. D.
2012epsc.conf..556B Altcode: 2012espc.conf..556B
There is currently a more diverse range of observatories scattered
around the solar system than at any time in the past. As a consequence,
heliophysics - the study of the effect of the Sun on the Solar System
- has entered a boom period. The Heliophysics Integrated Observatory,
HELIO, has established a collaborative environment where scientists can
discover, understand and model the connection between solar phenomena,
interplanetary disturbances and their effects on the planets. The
project is designed around a serviceoriented architecture with needed
capabilities that support metadata curation and search, data location
and retrieval, and data processing and storage being established as
independent services. HELIO provides integrated access to the data
and metadata from the domains that constitute heliophysics - solar,
heliospheric, geophysics and planetary. More than 50 event catalogues
can be used in the search, together with10 feature catalogues;
data from more than 150 instruments from nearly 50 observatories
can be accessed. A comprehensive user interface is available and the
services can also be accessed through IDL; a workflow tool provides
the ability to combine services together and it is possible to execute
programmes on demand including propagation models. We will show how
HELIO can be used to explore how phenomena evolve as they propagate
through the Solar System. Effects related to structures in the solar
wind, coronal mass ejections and particle events are reported using
observations from multiple platforms, including occasions where the
same phenomenon interacts with multiple planetary environments. The
HELIO Consortium includes thirteen groups from the UK, France, Ireland,
Italy, Switzerland, Spain and the US; the project started in June 2009
and has a duration of 42 months.
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Title: HELIO: A Heliospheric Virtual Observatory
Authors: Aboudarham, J.; Bentley, R. D.; Csillaghy, A.
2012ASPC..461..255A Altcode: 2012adass..21..255A
HELIO, the Heliophysics Integrated Observatory, is a Research
Infrastructure funded under EC's FP7 Capacities Specific Programme. It
began in June 2009 for three years. It will provide the heliophysics
research community with an integrated e-infrastructure that
has no equivalent anywhere else. The project objectives are as
follows: - to create a collaborative environment where scientists
can discover, understand and model the connection between solar
phenomena, interplanetary disturbances and their effects on the
planets (esp. the Earth) - to establish a consensus on standards
for describing all heliophysical data and champion them within
international standards bodies, e.g. the IVOA - to develop new ways
to interact with a virtual observatory that are more closely aligned
with the way researchers wish to use the data. HELIO is based on a
Service-Oriented architecture. For this purpose, HELIO developed a
Front End, which facilitates the search for data, using series of search
metadata services covering different domains (many Events and Features
available; use of context information to refine selection); Services
to identify and retrieve observations based on search results (knows
which data are stored where and how to access them); Enabling services
such as tools to find and track events/phenomena in 4D environment
(i.e. including the propagation of phenomena). Services can be used
individually or combined through workflow capability. Heliophysics
Event Catalogue and Heliophysics Features Catalogue provide a specific
access to information concerning phenomena that occur in the Solar
system. A semantic-driven approach is used to integrate data from
different domains, based on ontology derived from existing data
models. Thirteen partners from Europe and US are involved in this
project. And although it is not completed, a prototype is already
available, which can be accessed through HELIO web site (<a
href='http://www.helio-vo.eu/'>http://www.helio-vo.eu/</a>).
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Title: The role of e-Infrastructures supporting Solar System science
within general research environments
Authors: Bentley, R. D.
2012epsc.conf..557B Altcode: 2012espc.conf..557B
Many aspects of Solar System science are related with phenomena
observed on the Sun subsequently causing effects in other parts of
the Solar System; similarly, effects that originate in heliopshere
or the near planetary environments can have impacts low down in
planetary atmospheres. However, combining and comparing observations
from the different domains is more difficult that it should be,
partly because the communities have evolved independently without
any consideration of the need for interoperability. A number of
e-Infrastructures have been established to support the analysis
in different aspect of science within the Solar System - some have
been funded under FP7 including Europlanet RI and HELIO. Now that
the Research Infrastructures are reaching maturity it is important
to examine how they might work better together and be combined to
support new types of science. The infrastructure established by HELIO
follows a service oriented architecture where required capabilities are
implemented as independent services that cam be combined as needed. If
the capabilities of other infrastructures can be made available in
a similar way then it is possible to consider them all as components
in a larger and more general collaborative research environment that
can be used to address science use cases that were previously not
possible. We discuss how this might be achieved and describe some
of the ideas being developed under the Coordination Action for the
integration of Solar System Infrastructure and Science (CASSIS).
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Title: A Collaborative Research Environment for Heliophysics
Authors: Bentley, R. D.; Berghmans, D.; Csillaghy, A.
2012EGUGA..1412873B Altcode:
Heliophysics is the study of the effect of the Sun on the Solar
System; it is a relatively new science that combines the solar,
heliospheric, geophysics and planetary communities. The subject is
an example of the increasing desire to address science problems that
span disciplinary boundaries and provides a good example of the issues
involved. The communities that constitute heliophysics have grown up
independently and there are differences in the way that their data
are stored and used. Although a number of capabilities relevant to
heliophysics have been established under auspices of various projects
and organisations, the fact that they have not followed any underlying
strategy is now inhibiting our ability to do this type of science. The
Heliophysics Integrated Observatory (HELIO), a research infrastructure
funded under Capacities programme of the EC's 7th Framework Programme
(FP7), was designed around a service-oriented architecture with needed
capabilities that support metadata curation and search, data location
and retrieval, and data processing and storage being established as
independent services. In addition, a number of virtual observatories
have been established that address aspects of the overall problem
of heliophysics within the NASA's Heliophysics Science Division. We
examine the capabilities of these resources and look at where their
strengths and weaknesses lie. We identify some of the steps that are
needed to improve interoperability between the initiatives and consider
how they could be brought together to form a Collaborative Research
Environment for Heliophysics (CREH). The Coordination Action for the
integration of Solar System Infrastructure and Science (CASSIS) has the
objective of exploring ways to improve interoperability for all aspects
of Solar System Science. CASSIS is funded under Capacities specific
programme of the European Commission's Seventh Framework Programme
(FP7) and grew out of the HELIO, Europlanet RI and SOTERIA projects;
it also includes other key partners such as NASA, ESA, and NOAA. We
welcome participation by other interested organisations
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Title: HELIO - A Research Environment for Heliophysics
Authors: Bentley, R. D.; Abourdarham, J.; Csillaghy, A.; Messerotti,
M.; Gallagher, P.; Bocchialini, K.; Jacquey, C.; Hapgood, M.
2012EGUGA..1411634B Altcode:
HELIO, the Heliophysics Integrated Observatory, is a research
infrastructure funded under Capacities programme of the EC's 7th
Framework Programme (FP7). It provides a collaborative environment where
scientists can discover, understand and model the connection between
solar phenomena, interplanetary disturbances and their effects on the
planets. The project is designed around a service-oriented architecture
with needed capabilities that support metadata curation and search,
data location and retrieval, and data processing and storage being
established as independent services. HELIO provides integrated access
to the data and metadata from the domains that constitute heliophysics
- solar, heliospheric, geophysics and planetary. More than 50 event
catalogues can be used in the search, together with just under 10
feature catalogues; data from more than 150 instruments from nearly
50 observatories can be accessed. A comprehensive user interface
is available and the serves can also be accessed through IDL; a
workflow tool provides the ability to combine services together and
it is possible to execute programmes on demand including propagation
models. We will report on the status of HELIO and the services that are
available and demonstrate how these resources can be used to address
use cases involving multiple spacecraft and modelling. We will also
describe how we hope to combine the tools developed by HELIO into a
Collaborative Research Environment for Heliophysics. We have been
holding a series of Coordinated Data Analysis Workshops (CDAW) in
which we demonstrate the capabilities of the project and participants
are able to use them to address science use cases. Two CDAWs have been
held so far, in Dublin and Trieste; a third will be held in February
2012 in Orsay, and a fourth is planned in May/June 2012. Typical use
cases relate to phenomena propagating from the Sun and being observed
by at least two observatories in different parts of the inner Solar
System. The HELIO Consortium includes thirteen groups from the UK,
France, Ireland, Italy, Switzerland, Spain and the US; the project
started in June 2009 and has a duration of 36 months
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Title: Automated detection and tracking of solar and heliospheric
features in the frame of the European project HELIO
Authors: Bonnin, X.; Aboudarham, J.; Fuller, N.; Renie, C.;
Perez-Suarez, D.; Gallagher, P.; Higgins, P.; Krista, L.; Csillaghy,
A.; Bentley, R.
2011sf2a.conf..373B Altcode:
In the frame of the European project HELIO, the Observatoire de
Paris-Meudon is in charge of the Heliophysics Feature Catalogue (HFC),
a service which provides access to existing solar and heliospheric
feature data. In order to create a catalogue as exhaustive as possible,
recognition codes are developed to automatically detect and track
features. At the time, HFC contains data of filaments, active regions,
coronal holes, sunspots and type III radio bursts for a full solar
cycle. The insertion of prominences and type II radio bursts should
be done in the short term. We present here an overview of some of
the algorithms used to populate HFC. The development of such fast
and robust techniques also addresses the needs of the Space Weather
community in terms of near real-time monitoring capabilities.
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Title: The need for Standards when building Virtual Observatories
Authors: Bentley, R. D.; Csillaghy, A.; Aboudarham, J.; Messerotti,
M.; Jacquey, C.; Capria, M. T.
2011AGUFMSM21A2002B Altcode:
The Heliophysics Integrated Observatory, HELIO, has been established
based on a service-oriented architecture (SAO) under which the required
capabilities are provided as set of independent services that can be
used and combined as required. The main services fall into two general
groups: identifying interesting events and phenomena and locating and
retrieving suitable observations; there are also a number of enabling
services such as the Registry, processing and storage services,
coordinate transformation, etc. The HELIO services can be addresses
through SOAP and REST interfaces that are based on protocols developed
by the IVOA; for several services Web GUIs are also provided. Most
services can produce outputs in a number of formats although the
preferred one is VOTable, another product of the IVOA. It is important
that projects are able to build on each other's services. By developing
and employing standards, some services of HELIO are of immediate use to
other projects while other could be with some modifications. Adopting
the VOTable format has meant that it is possibly to fully describe each
parameter in the table using annotation, unambiguously defining what
the parameter represents. This approach makes it simpler for a service
from a different domain to use the products of HELIO; the same ought to
be true for other projects. In this paper we will present what has been
achieved so far and how this can help define and refine a broader set
of protocols. Some of this work is being done in conjunction with the
CASSIS project that is trying to encourage the adoption of standards
to increase the interoperability between domains. The HELIO and CASSIS
projects are funded under the European Commission's Seventh Framework
Programme (FP7).
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Title: Using HELIO to address use cases involving multi-point
observations from different parts of the Solar System.
Authors: Bentley, R. D.
2011epsc.conf..861B Altcode: 2011DPS....43..861B
The Heliophysics Integrated Observatory, HELIO, is creating
a distributed network of services that will address the needs of a
broad community of researchers in heliophysics. It provides integrated
access to data from the solar and heliospheric communities, and to
magnetospheric and ionospheric data from the geophysics and planetary
communities. HELIO is now in its third year and almost all the services
define in the architectural design have been deployed and can be used
by the community. It can be used to address science use cases that
span disciplinary boundaries and the capabilities of the project are
evolving as the system is being used in this way. Many of the services
have important capabilities but two key achievements are that the event
catalogue contains more than 40 event lists from various communities
and the access service provides access to more than 160 instruments
from over 45 observatories. We will report on the current status of
the and illustrate how HELIO can be used to address some of the use
cases. HELIO is a Research Infrastructures funded under the Capacities
Specific Programme within the European Commission's Seventh Framework
Programme (FP7; Project No. 238969).
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Title: CASSIS - Standards and Interoperability in Solar System Science
Authors: Bentley, R. D.
2011epsc.conf..862B Altcode: 2011DPS....43..862B
There is an increasing desire to address science problems that
span many disciplines; in heliophysics this includes solar and
heliospheric physics, planetary science, and magnetospheric and
ionospheric physics. However, differences in the way that data are
stored and used by the communities involves are inhibiting our ability
to do this type of science. We examine virtual observatories and data
archives that are available in heliophysics and related disciplines,
compare their capabilities and look at where their strengths and
weaknesses lie. We identify some of the steps that are needed to
improve interoperability between the VO initiatives and propose that
discussions under the auspices of CASSIS could help us globally to
move towards this overall objective. The Coordination Action for the
integration of Solar System Infrastructure and Science, CASSIS, is
funded under Capacities specific programme of the European Commission'
Seventh Framework Programme (FP7) and has the objective of exploring
ways to improve interoperability for all aspects of Solar System
Science. CASSIS grew out of the HELIO, Europlanet RI and SOTERIA
projects and also includes other key partners, including NASA, ESA,
and NOAA. We welcome participation by other interested organisations.
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Title: HELIO: The Heliophysics Integrated Observatory
Authors: Bentley, R. D.; Csillaghy, A.; Aboudarham, J.; Jacquey, C.;
Hapgood, M. A.; Bocchialini, K.; Messerotti, M.; Brooke, J.; Gallagher,
P.; Fox, P.; Hurlburt, N.; Roberts, D. A.; Duarte, L. Sanchez
2011AdSpR..47.2235B Altcode:
Heliophysics is a new research field that explores the Sun-Solar System
Connection; it requires the joint exploitation of solar, heliospheric,
magnetospheric and ionospheric observations.HELIO, the Heliophysics
Integrated Observatory, will facilitate this study by creating an
integrated e-Infrastructure that has no equivalent anywhere else. It
will be a key component of a worldwide effort to integrate heliophysics
data and will coordinate closely with international organizations to
exploit synergies with complementary domains.HELIO was proposed under a
Research Infrastructure call in the Capacities Programme of the European
Commission’s 7th Framework Programme (FP7). The project was selected
for negotiation in January 2009; following a successful conclusion to
these, the project started on 1 June 2009 and will last for 36 months.
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Title: The First Steps of the Heliophysics Integrated Observatory
Authors: Csillaghy, A.; Felix, S.; Bentley, R. D.; Blanc, A. L.;
Helio Team
2010ASPC..434..237C Altcode: 2010adass..19..237C
HELIO is the new European VO for solar and heliophysics. It develops
a collection of web services that span an information space and
make it possible to study solar activity and its effects on the solar
system. The infrastructure is developed iteratively, where functionality
slowly adds up in frequent releases and short iterations. The services
are integrated by the Taverna workflow orchestration tool.
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Title: VOs and Heliophysics: Would anyone like some CASSIS?
Authors: Bentley, R. D.; Lapenta, G.; Blanc, M.; Fox, P.; Walker,
R. J.; Cassis Team
2010AGUFMIN23B1358B Altcode:
Virtual Observatories related to heliophysics have emerged in various
regions of the World. Partly because of their sources of funding the
emphasis they place on aspects of the problem differ and how well
they can be integrated with other capabilities varies to a greater or
lesser degree. We examine virtual observatories that are available in
heliophysics and related disciplines and compare their capabilities and
look at where their strengths lie. We also identify some of the steps
that are needed to improve interoperability between the VO initiatives
and propose that discussions under the auspices of CASSIS could
help us globally to move towards this overall objective. CASSIS, the
Coordination Action for the integration of Solar System Infrastructure
and Science, is funded under Capacities specific programme of the
European Commission' Seventh Framework Programme (FP7) and has the
objective of exploring ways to improve interoperability for all aspects
of Solar System Science. CASSIS grew out of the HELIO, Europlanet RI
and SOTERIA projects and also includes other key partners, including
NASA, ESA, and NOAA. We welcome participation by other interested
organisations.
---------------------------------------------------------
Title: HELIO - First Services of The Heliophysics Integrated
Observatory
Authors: Csillaghy, A.; Bentley, R. D.
2010AGUFMIN23B1359C Altcode:
Heliophysics is a new science exploring the Sun-Solar System
connection. It spans the existing domains of solar, heliospheric,
magnetospheric and ionospheric physics. Heliophysics influences the
environments studied by the planetary and geosciences and also has
relevance for the astrophysics community. HELIO is an e-Infrastructure
project funded by the European Union 7th Framework Program. It develops
services to support integrated access to metadata and data from the
domains that constitute heliophysics. It also develop services to
explore and mine the data space spanned by the information providers
of the domains. Building up on these services, it constructs complex
queries, for instance to find observations that track phenomena as
they propagate through interplanetary space and affect the planetary
environments. The infrastructure is based on a service-oriented
architecture. It is designed to support locating and retrieving of
data associated with the desired observations. Services in development
are divided into four categories: catalog services (what phenomena are
interesting?), instrument location services (what instruments observed
the phenomena?), data access services (where are the associated
data?), and advanced services (what can I do with these data?). A
registry service allows keeping track of the resources managed by the
infrastructure. HELIO services are established as stand-alone, so they
can be used individually. Nevertheless, constructing complex queries
requires combining services into workflows. The workflow orchestration
tool used is called Taverna. To combine the resources from the different
heliophysics communities, HELIO uses a semantic-driven approach which
describe the relationships between the domains involved, therefore
avoiding to impose a specific name space. HELIO is in its 2nd year
of development. At this time, the basic services are available and
being tested. For instance, the Heliophysics Event Catalog compiles
an exhaustive list of solar phenomena. Focus is increasingly given
on constructing classes of workflows able to address specific science
objectives.
---------------------------------------------------------
Title: HELIO - A step into the Future
Authors: Bentley, R.
2010epsc.conf..870B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: HELIO - The Heliophysics Integrated Observatory
Authors: Bentley, R. D.; Csillaghy, A.; Abourdarham, J.
2010EGUGA..1215437B Altcode:
HELIO, the Heliophysics Integrated Observatory, is a research
infrastructure funded under Capacities programme of the EC's 7th
Framework Programme (FP7). The project is creating a collaborative
environment where scientists can discover, understand and model the
connection between solar phenomena, interplanetary disturbances and
their effects on the planets (esp. the Earth) HELIO will provide
integrated access to metadata from the domains that constitute
heliophysics - solar, heliospheric, magnetospheric and ionospheric
physics - in order to track phenomena as they propagate through inter
planetary space and affect the planetary environments. It will provide
services to locate and retrieve the desired observations and return them
to the user. HELIO is designed around a service-oriented architecture
(SAO); many of the resources are being established as stand-alone
services that support metadata curation and search, data location and
retrievel, data processing and storage; it will be possible to use
the services independently or bound into a system through a workflow
capability. We will describe the architecture of HELIO report on the
status of its development, including when individual services will
become available and what their capabilities will be. The project has a
strong Networking component and through this we wish to involve other
groups and individuals who can help us achieve our goals. One of the
main ways that we will involve the community is through a series of
Coordinated Data Analysis Workshops (CDAWs); we will describe the
preparation for the first of these which will be held in November
2010. The HELIO Consortium includes thirteen groups from the UK, France,
Ireland, Italy, Switzerland, Spain and the US; the project started in
June 2009 and has a duration of 36 months.
---------------------------------------------------------
Title: Using HELIO as tool for Research into Space Weather
Authors: Bentley, R. D.; Messerotti, M.; Aboudarham, J.; Hapgood,
M.; Jacquey, C.; Helio Team
2010EGUGA..1215417B Altcode:
HELIO, the Heliophysics Integrated Observatory, is a research
infrastructure funded under Capacities programme of the EC's 7th
Framework Programme (FP7). The project is creating a collaborative
environment where scientists can discover, understand and model the
connection between solar phenomena, interplanetary disturbances and
their effects on the planets. HELIO will provide integrated access
to metadata from the domains that constitute heliophysics - solar,
heliospheric, magnetospheric and ionospheric physics - in order to
track phenomena as they propagate through inter planetary space and
affect the planetary environments. It will provide services to locate
and retrieve the desired observations and return them to the user. The
capabilities provided by HELIO will allow the user to undertake
extensive studies of the origins of events that produce space weather
effects on the Earth's environment. It will also make it possible to
follow the causal phenomena as they pass through other parts of the
Solar System. We will discuss these possibilities giving examples of
how the services provided by HELIO can be used as part of a work flow
or as stand-alone capabilities. Although the HELIO infrastructure
is not specifically designed to provide real-time access to data,
it might be possible to support such access if resources that are
included have this capability. This will also be discussed. The HELIO
Consortium includes thirteen groups from the UK, France, Ireland,
Italy, Switzerland, Spain and the US; the project started in June 2009
and has a duration of 36 months
---------------------------------------------------------
Title: Data Management within the HELIO project
Authors: Bentley, Robert; Jacquey, Christian; Messerotti, Mauro;
Csillaghy, Andre; King, Todd; Perry, Chris
2010cosp...38..813B Altcode: 2010cosp.meet..813B
The Heliophysics Integrated Observatory, HELIO, is creating a
collaborative environment where scientists can discover, understand
and model the connection between solar phenomena, inter-planetary
disturbances and their effects on the planets. Of necessity HELIO has to
address data providers in a number of different and well established
communities, each with its own way of describing and handling the
data; the capabilities of the providers and means of access to
the data also vary considerably. HELIO is being developed around a
service-oriented architecture and the search for interesting events
an phenomena, and the task of then finding and retrieving the data
has been split into a number of services that can be used either as
part of a work flow or independently. We will describe the techniques
that we are developing for the project and will also highlight some
areas where a joint approach by the the wider community is required
to address some issues. The type of access that HELIO will afford is
also of interested to related communities, including the planetary
and geo-sciences, and astrophysics. It is therefore important that
the products of HELIO are interoperable those communities and where
possible we have tried to build on standards developed by bodies such
as the IVOA, IPDA, IAU, etc. HELIO is a research infrastructure funded
under Capacities programme of the EC's 7th Frame-work Programme (FP7);
the project started in June 2009 and has a duration of 36 months. The
HELIO Consortium includes thirteen groups from the UK, France, Ireland,
Italy, Switzerland, Spain and the US.
---------------------------------------------------------
Title: Using HELIO to study cross-disiplinary science problems using
data from multiple spacecraft
Authors: Bentley, Robert; Aboudarham, Jean; Messerotti, Mauro; Jacquey,
Christian; Gallagher, Peter T.; Hapgood, Mike; Bocchialini, Karine
2010cosp...38.1917B Altcode: 2010cosp.meet.1917B
The Heliophysics Integrated Observatory, HELIO, is creating a
collaborative environment where scientists can discover, understand
and model the connection between solar phenomena, inter-planetary
disturbances and their effects on the planets. HELIO will provide
integrated access to data from the solar, heliospheric, geophysics
and plan-etary domains and allow the user to undertake a search for
interesting events and phenomena based solely on metadata and data
products. The HELIO infrastructure will provide services to support
the search that can either be used independently or as part of a work
flow. The services include event and feature catalogues derived from
data from all the domains and a processing capability that will use
models to relate observations made in different part of the solar
system. We will describe how HELIO can be used to address science
problems that span the domains by allowing the user to track phenomena
as they propagate through the solar system and report on progress
to date. HELIO is a research infrastructure funded under Capacities
programme of the EC's 7th Frame-work Programme (FP7); the project
started in June 2009 and has a duration of 36 months. The HELIO
Consortium includes thirteen groups from the UK, France, Ireland,
Italy, Switzerland, Spain and the US.
---------------------------------------------------------
Title: HELIO as a Space Weather tool
Authors: Bentley, Robert; Hapgood, Mike; Messerotti, Mauro; Aboudarham,
Jean; Jacquey, Christian; Fox, Peter
2010cosp...38.4171B Altcode: 2010cosp.meet.4171B
The Heliophysics Integrated Observatory, HELIO, is primarily designed
to support research into the connection between solar phenomena,
interplanetary disturbances and their effects on the planets. However,
many of the techniques that are being developed and standards that we
are proposing have direct relevance to the more immediate requirements
of the space weather community. HELIO is being developed around
a service-oriented architecture and the services that can be used
either independently or as part of a work flow. The HELIO event and
feature catalogues, context service and metadata evaluation service may
all be of use to the community as capa-bilities in their own right;
they could also be combined in workflows that are specific to the
needs of research into space-weather. We have been examining ways of
enhancing the quality of the output produced by the services by adding
annotation that is compliant with standards proposed by the IVOA,
IPDA and IAU; if adopted across the space weather community these
additions could improve the interoperability of our data products
with related communities. Of necessity HELIO has to address data
providers in a number of different and well estab-lished communities,
each with its own way of describing and handling the data; in addition,
the capabilities of the providers and means of access to the data also
vary considerably. We have therefore had to develop techniques to handle
this, including archives where interesting observations may be available
but not easily accessible. HELIO is a research infrastructure funded
under Capacities programme of the EC's 7th Frame-work Programme (FP7);
the project started in June 2009 and has a duration of 36 months. The
HELIO Consortium includes thirteen groups from the UK, France, Ireland,
Italy, Switzerland, Spain and the US.
---------------------------------------------------------
Title: Addressing Science Use Cases with HELIO
Authors: Bentley, R. D.; Aboudarham, J.; Csillaghy, A.; Jacquey,
C.; Hapgood, M. A.; Messerotti, M.; Gallagher, P.; Bocchialini, K.;
Hurlburt, N. E.; Roberts, D.; Sanchez Duarte, L.
2009AGUFMSH54A..06B Altcode:
The Heliophysics Integrated Observatory (HELIO) is a new VO project
funded under the EC's Seventh Framework Programme (FP7). It includes
thirteen partners scattered over six countries and is led by University
College London. HELIO is designed to support the heliophysics community
and is based on a Service Oriented Architecture. The services developed
by and integrated into HELIO can be used to address a wide range
of science problems; they can be used individually or as part of a
work-flow driven search engine that can use a propagation (or other)
model to help locate obervations that describe interesting phenomena. We
will describe and discuss how the components of HELIO could be used
to address science use cases, particularly how a user can adapt the
work flow to their own science interests. Networking is one of the
three Activities of the HELIO Integrated Infrastructure Initiatives
(I3) project. Within this activity we plan to involve the community in
all aspects of the design and testing of the HELIO system, including
determining which data and metadata should be included, how the quality
and content of metadata can be included, etc. We are investigating ways
of making HELIO "domain-aware" so that researchers who are specialists
in one of the communities that constitute heliophysics can easily
identify, access and use data they need from the other communities. We
will discuss how the community can help us develop this capability.
---------------------------------------------------------
Title: Science, VxOs and Just In Time Information
Authors: King, T. A.; Walker, R. J.; Merka, J.; Bentley, R. D.;
Roberts, A.; Rankin, R.; Candey, R. M.; Narock, T. W.
2009AGUFMSH51B1285K Altcode:
The scientific method is a system for acquiring knowledge based on
the collection of data through observation, experimentation and the
integration of previous knowledge. This is followed by the formulation
and testing of hypotheses resulting in new knowledge and possibly the
correction previous knowledge. From a system design perspective the
scientific method is a well defined system, use cases are abundant,
requirements are readily accessible and guiding principles are
fully articulated. With advancement of technology new implementations
emerge to support and enable science. We are now in the age of Virtual
Observatories where distributed data are coupled through services and
well-defined metadata. The paradigm is one in which information is
sought and retrieved just in time for its use. We discuss a system
model for a Just In Time Information (JITI) system that addresses
the clearly identified needs of scientists. It includes tasks such as
coordinate system conversion, file format transformation, subsetting,
aggregation, and rendering. We also discuss the discovery needs of the
scientist which range from the initial discovery of available resources
to complex scientific queries. Overall the system is composed of a
collection of small services which are tied together on a task-by-task
basis, similar to that of a workflow, but with distributed and loosely
coupled components. In a JITI system each service is invoked as needed
with unique resource identifiers passed as the common reference thread
that enables the service integration. The services that are part of a
JITI system can be utilized in a number of ways to implement portals,
search engines, aggregators, and mash-ups. JITI-like systems are
emerging in the Virtual Observatory communities. We look at NASA's
Virtual Magnetospheric Observatory, the Heliophysics Event List Manager
(HELM), Europe's HELIO project and Canada's CSSDP project as examples.
---------------------------------------------------------
Title: HELIO and EuroPlaNet IDIS
Authors: Bentley, R. D.
2009epsc.conf..814B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: HELIO - The Heliophysics Integrated Observatory
Authors: Bentley, R. D.; Csillahghy, A.; Aboudarham, J.
2009epsc.conf..744B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Payloads with Resource-Efficient Integration for Science
Missions (PRISM)
Authors: Emam, O.; FitzGeorge, T.; Whittaker, A.; Wishart, A.; Fowell,
S.; Prochazka, M.; Bentley, R.; Cole, R.; Brown, P.; Carr, C.; Cupido,
E.; Oddy, T.
2009ESASP.669E...7E Altcode:
PRISM is a collaborative industry and academia project to demonstrate
the practicality of a highly integrated payload processing architecture,
in order to exploit improvements in spacecraft computer performance to
reduce multi-instrument payload mass and power requirements. Integrated
architectures also provide opportunities for a greater degree
of autonomy and advanced target selection (e.g. inter-instrument
triggering). The PRISM architecture has potential advantages for
missions such as EJSM (Europa Jupiter System Mission) or Solar
Orbiter. The key technology objectives of PRISM are application
partitioning on a qualifiable operating system, supported by the
software required for fault-tolerant centralised processing, and the
development of an application development environment for writing
and testing instrument control applications. A working demonstrator
has been implemented on a LEON3 platform, with representative payload
applications from an in-situ magnetometer and a remote sensing extreme
ultra-violet imager, both proposed for Solar Orbiter. PRISM is supported
by the UK Science and Technology Facilities Council (STFC).
---------------------------------------------------------
Title: HELIO - The Heliophysics Integrated Observatory
Authors: Bentley, R. D.; Csillaghy, A.; Abourdarham, J.
2009EGUGA..1110375B Altcode:
Heliophysics is a new science that explores the Sun-Solar System
connection and spans the existing domains of solar, heliospheric,
magnetospheric and ionospheric physics. Heliophysics influences the
environments studied by the planetary and geo-sciences and also has
relevance for the astrophysics community. HELIO, the Heliophysics
Integrated Observatory, with provide integrated access to metadata from
the domains that constitute heliophysics in order to facilitate the
search for observations that track phenomena as they propagate through
inter planetary space and affect the planetary environments. It will
provide services to locate and retrieve the desired observations and
return them to the user in the format they require. HELIO is designed
around a service-oriented architecture (SAO); many of the resources
will be established as stand-alone services that support metadata
curation and search, data location and retrievel, data processing
and storage. It will be possible to use the services independently or
bound into a system through a workflow capability. A semantic-driven
approach will be used to describe the relationships between the domains
and support the search and data retrieval capabilities. The HELIO
Consortium includes twelve groups from the UK, France, Ireland, Italy,
Switzerland and the US. The project has a strong Networking component
and through this we wish to involve other groups and individuals who
can help us achieve our goals. The HELIO proposal was submitted under
the EC's 7th Framework Programme.
---------------------------------------------------------
Title: Building a Virtual Observatory for Heliophysics
Authors: Bentley, R. D.
2009EM&P..104...87B Altcode:
Heliophysics is a new discipline that studies of the effect of the
Sun on the Solar System and spans a number of existing scientific
domains—solar physics, heliospheric physics, and magnetospheric
and ionospheric physics. In order to build a virtual observatory for
heliophysics we have to find ways to conduct searches that span the
domains and track the evolution of phenomena in 4 dimensions as they
propagate through interplanetary space. To facilitate this it will
be necessary to improve the quality of the metadata that are used in
the search and to describe the observations. We describe some of the
issues and how these can be addressed.
---------------------------------------------------------
Title: Division XII / Commission 5 / Working Group Virtual
Observatories, Data Centers & Networks
Authors: Hanisch, Robert J.; Barbuy, Beatriz; Bentley, Robert D.;
Benvenuti, Piero; Egret, Daniel; Fukushima, Toshio; Genova, Françoise;
Grosbol, Preben J.; Helou, George; Norris, Raymond P.; Quinn, Peter
2009IAUTA..27..369H Altcode:
The Working Group Virtual Observatories, Data Centers, and Networks
was established under Commission 5 at the Prague General Assembly
in 2006. The purpose of the WG is to provide IAU oversight of the
activities of the International Virtual Observatory Alliance (IVOA,
<www.ivoa.net/>), to encourage data centers and other data
providers to archive and publish data according to IVOA standards, and
to help assure that astronomical research facilities are electronically
linked with current network technologies. The WG coordinates activities
closely with the WG-FITS, as the IVOA uses FITS as its primary format
for binary data exchange, and the WG on Astronomical Data.
---------------------------------------------------------
Title: Accessing the EGSO Grid through a WSRF-Enabled API
Authors: Csillaghy, A.; Soldati, M.; Kunz, P.; Bentley, R. D.;
Scholl, I.
2006ASPC..351..536C Altcode: 2006adass..15..536C
EGSO is part of the Virtual Solar Observatory. It provides a Grid
for integrated access to distributed and heterogeneous solar data
archives. Here we describe the motivation and approach we have chosen
to implement the Grid access as a stateful web service. Using this
kind of service allows us to consider the search and retrieval of data
as an interaction between the client and the Grid. This way, the EGSO
service can be merged into interactive data analysis systems such as
Python or IDL.
---------------------------------------------------------
Title: The VO in Sunlight
Authors: Csillaghy, A.; Bentley, R. D.; Scholl, I.; Egso Team
2006vopc.conf..343C Altcode:
The European Grid of Solar Observations (EGSO, www.egso.org) is a grid
test platform that has been funded by the European Commission's Fifth
Framework Program under its Information Society Technologies (IST)
thematic priority. The goal of this 3-year project was to provide
enhanced access to solar and related data around the world. In this
paper we present the generic query model on which EGSO is built. We
then show, from a user point of view, how it can be used for evaluating
integrated queries that involve a large number of distributed data
archives. We further introduce the search registries and catalogs
on which EGSO services rely, and finally discuss the architecture of
our system.
---------------------------------------------------------
Title: A New Way to look at Observations with EGSO
Authors: Aboudarham, J.; Scholl, I.; Fuller, N.; Csillaghy, A.;
Bentley, R. D.; Antonucci, E.; Ciminiera, L.; Finkelstein, A.; Ipson,
S.; Messerotti, M.; Pike, D.; Vial, J. C.; Zharkova, V.
2006IAUS..233..229A Altcode:
The European Grid of Solar Observations (EGSO) is a Solar virtual
observatory (see Hill et al., 2002). It has been funded through the 5th
Framework Program of the European Community. A dozen of laboratories,
mixing Solar Physics and Information Technology, in Great Britain,
France, Italy and Swiss have been involved in this project during
3 years. A grid accessing several dozens of databases and archives
scattered all around the world has been developped as well as a Solar
Event Catalogue and a Solar Feature Catalogue. The original aspect
of this work consists in the possibility not only to search through
the characteristics of observations, but also search for available
data corresponding to specific kinds of events. So it is now very
important to be able to follow the Sun 24 hours a day in order to
enrich the events database for future queries. More informations on
EGSO, catalogues and user interface can be accessd through the web
site: http://www.egso.org/
---------------------------------------------------------
Title: European Grid of Solar Observations (EGSO)
Authors: Aboudarham, J.; Scholl, I.; Csillaghy, A.; Bentley, R. D.;
Antonucci, E.; Ciminiera, L.; Finkelstein, A.; Ipson, S.; Messerotti,
M.; Pike, D.; Vial, J. C.; Zharkova, V.
2006ihy..conf...18A Altcode:
The EGSO project addresses the problem of combining heterogeneous
data into a single "virtual" solar data resource. Wider access to
other catalogues is enabled, including both pre-existing lists and
new compilations generated using feature-recognition techniques on
existing data. Scientists are also able to perform much richer data
searches, based on solar events. Informations concerning EGSO can be
found at http://www.egso.org/
---------------------------------------------------------
Title: Active region AR484 tracking with Solar Feature Catalogue
Authors: Zharkova, V.; Benkhalil, A.; Zharkov, S.; Ipson, S.; Bentley,
R. D.
2006AdSpR..37.1152Z Altcode:
This paper presents a morphological analysis of the active region NOAA
AR 484 as well as its intensity and magnetic field variations associated
with flare occurrences. The active region is tracked during a one solar
rotation with the automated technique used in Solar Feature Catalogue
(SFC). The location and intensity parameters of region AR484 were
extracted from 1 minute cadence Hα solar images from the Big Bear
observatory (BBSO), SOHO/EIT images in Fe XII, 195 Å and the SOHO/MDI
magnetograms. During the whole period of tracking from October, 19
until November, 11, 2003 the AR484 produced many flares of different
significance including a few X-class flares. We investigate the total
AR intensity variations in each band leading to a flare production and
compare these with the magnetic field changes before and during a flare
for five flares of different significance. Based on this comparison the
key parameters defining the region activity in a flare production are
found that include the resulting, or excess, flux and the ratio between
areas covered by negative and positive pixels. These parameters can
be used for a preliminary pre-flare classification of active regions
in addition to other classifiers associated with a magnetic field.
---------------------------------------------------------
Title: EGSO - A maturing VO for Solar Physics
Authors: Bentley, R. D.; Scholl, I.; Csillaghy, A.; Aboudarham, J.;
Antonucci, E.; Gurman, J.; Hill, F.; Pike, D.; Vial, J.; Zharkova, V.
2005AGUSMSH43B..01B Altcode:
The European Grid of Solar Observations, EGSO, is a Grid test-bed
funded under the Information Societies Thematic Priority of the European
Commission's Fifth Framework Programme (FP5). In the case of EGSO, the
application chosen was the use of Grid technology to establish a virtual
observatory for solar physics, and the project addresses the generic
problem of how to provide access to a distributed, heterogeneous data
set for a scattered user community. In order to identify observations
that match a user's search criteria, EGSO has been building an
environment that will support complex searches. Because of the absence
of the metadata needed to tie the heterogeneous data together, EGSO has
placed emphasis on the provision of databases that can be accessed from
the Internet through special providers. The provision of appropriate
metadata is of extreme importance in establishing a virtual observatory,
and the approach used can be adapted to facilitate the inclusion of
any data, including non-solar data. We report on the capabilities of
EGSO and discuss experience gained in creating the facility. We also
discuss how EGSO has been working with other virtual observatories that
support the solar, heliospheric and space plasma communities in order
to try to achieve interoperability between the numerous data sets. We
highlight what we consider are the most profitable ways of doing this.
---------------------------------------------------------
Title: Using the Collaborative Sun-Earth Connector for integrating
data systems
Authors: Hurlburt, N.; Freeland, S.; Slater, G.; Bentley, R.; Hill,
F.; Bose, P.
2005AGUSMSH43B..05H Altcode:
We demonstrate the coupling of disjoint data systems into virtual
collaborative operations using the Collaborative Sun-Earth Connector
(CoSEC). In addition to demonstrating possible interactions between
Virtual observatories, we will present how individual missions and
researchers can integrate their systems with space science services
already incorporated into CoSEC. We present more advanced concepts of
how to create collaborative data environments using upcoming solar
missions as examples. This research has been supported through NASA
contract NNH04CC00C.
---------------------------------------------------------
Title: The User Interface of the European Grid of Solar Observations
Authors: Scholl, I. F.; Bentley, R. D.; Csillaghy, A.
2005AGUSMSP51A..05S Altcode:
The European Grid of Solar Observations (EGSO) is a grid testbed
funded by the European Commission's Fifth Framework Program under
its Information Society Technologies (IST) thematic priority. This
3-year project was designed to provide enhanced access to solar
and related data around the world. The services provided by EGSO
can be accessed through different interfaces. The main access is
a Web-based Graphical User Interface (GUI) that allows the user to
access the services offered by the grid in a common and integrated
way. Also, an Application Programming Interface (API) is available
in the SolarSoft package, that allows access to the services from IDL
applications. Furthermore, various dedicated web interfaces allow to
access individual catalogs built in the framework of this project,
such as the Solar Event Catalog (SEC), the Solar feature Catalog (SFC),
and the Unified Observing Catalog (UOC). In this paper we present the
final version of the Grid, featuring the latest GUI, the new IDL API,
as well as the access to the different catalogs and registries that
help resolving complex queries and route them through the appropriate
nodes of the Grid. The featured version of the GUI also provides users
with a new function that helps them to search for instruments based
only on some observational characteristics. In this final version, all
major and recent solar data sets are now accessible from EGSO. EGSO
is also closely coupled to the Collaborative Sun-Earth Connector
(CoSEC), another virtual observatory-related project, from which it
uses processing services. More information about EGSO can be found
under http://www.egso.org/
---------------------------------------------------------
Title: Filament Recognition and Image Cleaning on Meudon Hα
Spectroheliograms
Authors: Fuller, Nicolas; Aboudarham, Jean; Bentley, R. D.
2005SoPh..227...61F Altcode:
This paper presents the techniques developed for the automated detection
of filaments on Meudon Hα spectroheliograms, and, by extension, on
any full-disk Hα Sun observations. Some cleaning processes are first
applied to the images to correct them from defects characteristic of the
instrument. Indeed, these defects may lead to spurious detections. From
the cleaned images, filament areas are then segmented using a region
growing method which efficiently returns the full extent of these dark
areas. The filaments are finally described by means of their pruned
skeleton. This representation allows one to compare the automatically
segmented filaments with those manually recorded for Meudon Synoptic
Maps. The very good agreement observed on a representative set of
images confirms that this method can effectively be used in the frame
of the EGSO (European Grid of Solar Observations) project in order to
produce a reliable catalog dedicated to solar features.
---------------------------------------------------------
Title: Space weather and commercial airlines
Authors: Jones, J. B. L.; Bentley, R. D.; Hunter, R.; Iles, R. H. A.;
Taylor, G. C.; Thomas, D. J.
2005AdSpR..36.2258J Altcode:
Space weather phenomena can effect many areas of commercial airline
operations including avionics, communications and GPS navigation
systems. Of particular importance at present is the recently
introduced EU legislation requiring the monitoring of aircrew
radiation exposure, including any variations at aircraft altitudes
due to solar activity. With the introduction of new ultra-long-haul
“over-the-pole” routes, “more-electric” aircraft in the future,
and the increasing use of satellites in the operation, the need for
a better understanding of the space weather impacts on future airline
operations becomes all the more compelling. This paper will present the
various space weather effects, some provisional results of an ongoing
3-year study to monitor cosmic radiation in aircraft, and conclude by
summarising some of the identified key operational issues, which must
be addressed, with the help of the science community, if the airlines
want to benefit from the availability of space weather services.
---------------------------------------------------------
Title: Resik: A Bent Crystal X-ray Spectrometer for Studies of Solar
Coronal Plasma Composition
Authors: Sylwester, J.; Gaicki, I.; Kordylewski, Z.; Kowaliński,
M.; Nowak, S.; Płocieniak, S.; Siarkowski, M.; Sylwester, B.;
Trzebiński, W.; Bakała, J.; Culhane, J. L.; Whyndham, M.; Bentley,
R. D.; Guttridge, P. R.; Phillips, K. J. H.; Lang, J.; Brown, C. M.;
Doschek, G. A.; Kuznetsov, V. D.; Oraevsky, V. N.; Stepanov, A. I.;
Lisin, D. V.
2005SoPh..226...45S Altcode:
We describe the RESIK (REntgenovsky Spektrometr s Izognutymi Kristalami)
instrument, consisting of two double-channel X-ray spectrometers,
designed to observe solar active region and flare plasmas. RESIK is
one of the instruments making up the scientific payload of the Russian
CORONAS-F solar mission. The uncollimated spectrometer uses two silicon
and two quartz bent crystals observing flare, active region and coronal
spectra in four wavelength bands with a resolving power (λ/Δ λ)
of ∼1000. The wavelength coverage, 3.3-6.1 Å, includes emission
lines of Si, S, Cl, Ar, and K and in the third diffraction order,
the wavelength range includes He-like Fe lines (1.85 Å) and Ni lines
(1.55 Å) with dielectronic satellites, emitted during intense, hot
flares. The instrument is believed to be the best calibrated space-borne
crystal spectrometer flown to date. The spectrometer dynamically adjusts
the data gathering intervals from 1 s to 5 minutes, depending on the
level of solar X-ray emission at the time of observation. The principal
aims of RESIK are the measurements of relative and absolute element
abundances in the emitting plasma and the temperature distribution of
plasma (differential emission measure) over the temperature interval 3
and 50 MK. This paper summarizes the scientific objectives of RESIK
and describes the design, characteristics, and performance of the
instrument.
---------------------------------------------------------
Title: User Access to the European Grid of Solar Observations
Authors: Scholl, I. F.; Bentley, R. D.; Csillaghy, A.
2004AGUFMSH21B0416S Altcode:
The European Grid of Solar Observations (EGSO) is a grid testbed
funded by the European Commission's Fifth Framework Programme under
its Information Society Technologies (IST) thematic priority. The
project started in 2002 and is designed to provide enhanced access
to solar and related data around the world. One front-end of EGSO
is a Graphical User Interface (GUI) that allows the user to access
all the services offered by the grid from a common and integrated
interface. Other front-ends are an IDL API and various dedicated web
interfaces to access all the different catalogs built in the frame
of this project like the Solar Event Catalog (SEC) the Solar feature
Catalog (SFC) the Unified Observing Catalog (UOC). The GUI, as well
as the API, provides also users with external processing services like
those offered by the Collaborative Sun-Earth Connector (CoSEC), another
virtual observatory-like project. In this paper we will present the EGSO
front-ends with a special focus on the GUI. We will also demonstrate
interactions between catalogs and the query system underlying the user
interfaces in order to help the user when specifying complex scientific
queries and eventually retrieving the corresponding solar data. More
information about EGSO can be found under http://www.egso.org/
---------------------------------------------------------
Title: Solving Science Use Cases that relate to the Sun and
Heliosphere with EGSO
Authors: Bentley, R. D.; Scholl, I.; Csillaghy, A.; Aboudarham,
J.; Antonucci, E.; Gurman, J. B.; Hill, F.; Pike, D.; Vial, J.;
Zharkova, V.
2004AGUFMSH21B0415B Altcode:
The European Grid of Solar Observations (EGSO) is a grid testbed
funded by the European Commission's Fifth Framework Programme under
its Information Society Technologies (IST) thematic priority. The
project started in 2002 and is designed to provide enhanced access to
solar and related data around the world. The EGSO grid is composed
of two main components, Roles to set up the grid and, catalogs and
registries to allow roles to answer users queries. Catalogs are made
of lists of observations, events and features (a new service provided
by EGSO). Registries are built from these catalogs and organized in
order to enhance search capabilities. EGSO is working closely with
other virtual observatory (VO) projects in the solar physics and
related domains. This includes the US Virtual Solar Observatory (VSO)
and the Collaborative Sun-Earth Connector (CoSEC). More recently we
have been working with the Virtual Space Plasma Observatory (VSPO) and
have contact with the Virtual Heliospheric Observatory (VHO). Through
discussions with future missions, and within the new IAU Working
Group on “International Data Access” (Solar and Heliospheric),
the VOs are studying ways of ensuring interoperability from the
“sun to dirt”. This type of integrated access will be particularly
important to missions such as STEREO and Living Witha Star. In this
paper we will report the current status of EGSO, demonstrate how the
catalogs and registries model serves within the user interface, and
show how the user can retrieve solar and heliospheric data to match
a scientific query. EGSO Release 4 is now being Beta-tested by users
and anyone interested should view the Web page detailing all the EGSO
capabilities under http://www.egso.org/demo
---------------------------------------------------------
Title: Effect of solar energetic particle (SEP) events on the
radiation exposure levels to aircraft passengers and crew: Case
study of 14 July 2000 SEP event
Authors: Iles, R. H. A.; Jones, J. B. L.; Taylor, G. C.; Blake, J. B.;
Bentley, R. D.; Hunter, R.; Harra, L. K.; Coates, A. J.
2004JGRA..10911103I Altcode:
We investigate the circumstances required for aircrew and passengers
to experience an increased radiation exposure rate from a solar
energetic particle (SEP) event occurring during a flight. The effects
of the 14 July 2000 National Oceanic and Atmospheric Administration
S3 class SEP event are examined using ground-based and satellite
measurements together with coincident measurements made using a tissue
equivalent proportional counter (TEPC) on board a Virgin Atlantic
Airways flight from London Heathrow to Hong Kong. In this paper we
present the first measurements made during a SEP event using a TEPC at
flight altitudes. Our results indicate that there were no increased
radiation levels detected during the flight due to the SEPs, but the
measurements agreed well with the CARI-6 model calculations made using
a heliocentric potential value derived immediately prior to the SEP
event. In addition, a prolonged increase in the >85 MeV particle
flux is observed for up to 2 days after the SEP onset by the SAMPEX
spacecraft at latitudes >55°.
---------------------------------------------------------
Title: The European grid of solar observations
Authors: Bentley, Robert D.; Csillaghy, Andre; Scholl, Isabelle
2004SPIE.5493..170B Altcode:
The European Grid of Solar Observations (EGSO) is a Grid test-bed that
will change the way users analyze solar data. One of the major hurdles
in the analysis of solar data is finding what data are available and
retrieving those required. EGSO is integrating the access to solar data
by building a Grid including solar archives around the world. The Grid
relies on metadata and tools for selecting, processing and retrieving
distributed and heterogeneous solar data. EGSO is also creating a
solar feature catalogue giving for the first time the ability to
select solar data based on phenomena and events. In essence, EGSO is
providing the fabric of a virtual observatory. Since the first release
of EGSO in September 2003, members of the solar community have been
involved in product testing. The constant testing and feedback allows
us to assure the usability of the system. The capabilities of the
latest release will be described, and the scientific problems that
it addresses discussed. EGSO is funded under the IST (Information
Society Technologies) thematic priority of the European Commission's
Fifth Framework Programme (FP5) Ð it started in March 2002 and will
last for three years. The EGSO Consortium comprises 11 institutes from
Europe and the US and is led by the Mullard Space Science Laboratory
of University College London. EGSO is collaborating with other groups
in the US who are working on similar virtual observatory projects for
solar and heliospheric data with the objective of providing integrated
access to these data.
---------------------------------------------------------
Title: Virtual Solar Inc.
Authors: Bentley, R. D.; Hill, F.; Hurlburt, N.
2004ASPC..314..311B Altcode: 2004adass..13..311B
The need to develop new ways of accessing solar observations, coupled
with rapidly increasing volumes of data and the desire to share
data with other communities, has led to several projects intended
to create virtual solar observatories. We outline the three main
initiatives, EGSO, VSO and CoSEC, and describe how the the combined
effort will result in a facility that will better match the needs of the
community. Interaction with related communities are discussed, including
similarities and differences with the IVOA and interoperability.
---------------------------------------------------------
Title: TWiki: A Collaboration Platform for VO Projects
Authors: Leoni, M. C.; Dolensky, M.; Bentley, R.; Goodwin, T.;
Linde, T.
2004ASPC..314..307L Altcode: 2004adass..13..307L
Finding an easy way of sharing knowledge and experience in a
geographically dispersed project team is not easy. The TWiki is a
Web-based collaboration platform. It looks like a normal Internet web
site, but everybody can change pages or add content by just using
a browser. A revision control keeps track of changes. <P />Several
Virtual Observatory projects use this type of web site to share info
among project members and across projects. This is an experience report
on the usage and maintenance of TWiki sites in Astronomy. <P />Even
if at first it seems almost the opposite of how the Web and on-line
communications "normally" work, it is intuitive and aspires to the
Zen ideals known as Wabi-Sabi: "It finds beauty in the imperfect and
ephemeral and constantly evolving".
---------------------------------------------------------
Title: A Solar Data Model for Use in Virtual Observatories
Authors: Reardon, K. P.; Bentley, R. D.; Messerotti, M.; Giordano, S.
2004AAS...204.7003R Altcode: 2004BAAS...36Q.796R
The creation of a virtual solar observatories relies heavily on the
merging of the metadata describing different datasets into a common
form so that it can be handled in a standard way for all associated
resources. In order to bring together the varied data descriptions
that already exist, it is necessary to have a common framework on
which all the different datasets can be represented. The definition of
this framework is done through a data model which attempts to provide
a simplified but realistic description of the various entities that
make up a data set or solar resource. <P />We present the solar data
model which has been developed as part of the European Grid of Solar
Observations (EGSO) project. This model attempts to include many of
the different elements in the field of solar physics, including data
producers, data sets, event lists, and data providers. This global
picture can then be used to focus on the particular elements required
for a specific implementation. We present the different aspects of
the model and describe some systems in which portions of this model
have been implemented.
---------------------------------------------------------
Title: The European Grid of Solar Observations
Authors: Bentley, R. D.; Scholl, I.; Csillaghy, A.; Antonucci, E.;
Zharkova, V. V.; Abourdarham, J.; Pike, C. D.; EGSO Team
2004AAS...204.5206B Altcode: 2004BAAS...36R.754B
The European Grid of Solar Observations (EGSO) is a Grid test-bed funded
by the European Commission that will change the way users analyze solar
data. The project is tackling one of the major hurdles in the analysis
of solar data - identifying what data are available and retrieving those
that are needed. To do this, EGSO is creating new forms of metadata that
will speed the search process and for the first time provide the ability
to select data based on features,phenomena and events. <P />The project
completed its second year in March 2004 and is now on Release 4 of the
code. Since the first release in September 2003, members of the solar
community have been involved in product testing. The constant testing
and feedback allows us to assure the usability of the system. <P />We
will describe the capabilities of the latest release and discuss the
scientific problems that it is currently able to address.
---------------------------------------------------------
Title: Integrated Access to Solar Data using EGSO
Authors: Scholl, I.; Bentley, R.; Csillaghy, A.; EGSO Team
2004AAS...204.7005S Altcode: 2004BAAS...36..796S
The European Grid of Solar Observations (EGSO) is a virtual observatory
based on Grid technology funded under the IST (Information Society
Technologies) thematic priority of the European Commission's Fifth
Framework Programme (FP5). <P />EGSO allows the user to use metadata
catalogues to select solar data based on a number of criteria, including
a search based on events, features or phenomena. Since the first release
of EGSO in September 2003, members of the solar community have been
involved in product testing. The constant testing and feedback allows
us to continue to improve the quality and usability of the system. The
capabilities of the latest release (R4) will be demonstrated and
the scientific problems that it addresses discussed. <P />EGSO is
collaborating closely with groups in the US who are working on similar
virtual observatory projects for the solar, solar-terrestrial and
heliospheric communities with the objective of providing integrated
access to these data. In particular, strong synergies between the EGSO
and CoSEC projects are producing innovative ways of accessing the data
that will be deployed in both projects.
---------------------------------------------------------
Title: IAU Working Group on International Data Access for Solar and
Heliospheric data
Authors: Bentley, R. D.; Hill, F.; Hurlburt, N.; Roberts, A.
2004AAS...204.5207B Altcode: 2004BAAS...36S.754B
Division II (Sun and Heliosphere) of the IAU has initiated a Working
Group to study the archiving, retrieval and distribution of solar and
heliospheric data. The goal of the Working Group is to facilitate the
use of available solar and heliospheric data that are archived in
a large number of computers scattered all over the world. <P />The
intent of the Working Group is to help coordinate the existing and
growing data exchange through the Internet and work with the virtual
observatory initiatives to propose guidelines for exchange at an
international level and encourage participation in the projects. <P
/>The Working Group is working with the virtual observatory initiatives
to ensure that they develop standards and employ techniques that are
acceptable to the worldwide solar and heliospheric communities and
to encourage interoperability between the projects. The EGSO, VSO,
CoSEC and VSPO projects are all part of the Working Group and would
also like to encourage the communities to help develop standards and
participate in the virtual observatory projects. <P />The aims of and
objectives the Working Group will be discussed and feedback from the
audience is encouraged.
---------------------------------------------------------
Title: Tracking of Solar Active Regions and Search for Classification
parameters
Authors: Benkhalil, A.; Zharkova, V.; Bentley, R.; Zharkov, S.;
Ipson, S.
2004cosp...35.3115B Altcode: 2004cosp.meet.3115B
This paper presents the application of Solar Feature Catalogue (SFC)
created with an automated technique for active region detection from
SOHO/MDI, SOHO/EIT and Hα images from Meudon. The two active regions
(NOAA 484 and 486) producing many flares in October and November '03
were tracked during their lifetime on a solar disk in Hα and Fe XII,
195 Å wavelengths. These regions produced a large number of flares with
different significance including a few X-class flares. We investigate
their morphology and evaluation leading to a flare production and
compare these with the magnetic field changes before and during a
flare. In SFC each region is characterized by a number of physical and
photometric properties, which are stored in the database. These include:
the center of gravity in pixel and heliographic coordinates; minimum,
maximum and mean intensity within the active region; area in square
degrees and dimensions in pixels; contrast ratios; and a chain-code
representation of the active region boundary. Based on a comparison of
the active region parameters selected from the SFC with the magnetic
field configuration and strength we try to select the key parameters
defining a region activity in flare production that can be used for
a preliminary active region classification.
---------------------------------------------------------
Title: Space Weather affects on Air Transportation
Authors: Jones, J. B. L.; Bentley, R. D.; Dyer, C.; Shaw, A.
2004cosp...35.3522J Altcode: 2004cosp.meet.3522J
In Europe, legislation requires the airline industry to monitor
the occupational exposure of aircrew to cosmic radiation. However,
there are other significant impacts of space weather phenomena on the
technological systems used for day-to-day operations which need to be
considered by the airlines. These were highlighted by the disruption
caused to the industry by the period of significant solar activity
in late October and early November 2003. Next generation aircraft
will utilize increasingly complex avionics as well as expanding the
performance envelopes. These and future generation platforms will
require the development of a new air-space management infrastructure
with improved position accuracy (for route navigation and landing
in bad weather) and reduced separation minima in order to cope with
the expected growth in air travel. Similarly, greater reliance will
be placed upon satellites for command, control, communication and
information (C3I) of the operation. However, to maximize effectiveness
of this globally interoperable C3I and ensure seamless fusion of all
components for a safe operation will require a greater understanding
of the space weather affects, their risks with increasing technology,
and the inclusion of space weather information into the operation. This
paper will review space weather effects on air transport and the
increasing risks for future operations cause by them. We will examine
how well the effects can be predicted, some of the tools that can be
used and the practicalities of using such predictions in an operational
scenario. Initial results from the SOARS ESA Space Weather Pilot
Project will also be discussed,
---------------------------------------------------------
Title: Statistical analysis of long-term variations of the sunspot
and umbral magnetic field
Authors: Zharkov, S. I.; Zharkova, V. V.; Bentley, R. D.
2004cosp...35.3113Z Altcode: 2004cosp.meet.3113Z
Using the EGSO Solar Feature Catalogue for sunspots created from the
SOHO/MDI white light and magnetogram data for the period of 1995-2002
with the developed automated detection technique. The detected sunspots
overlaid with the SOHO/MDI magnetograms obtained for the corresponding
time periods. The magnetogram data is used for sunspot separation into
the groups corresponding to the active region and adding a positive
or negative polarity tag. The results are unified under the synoptic
maps of sunspots and magnetic structures. We present short term (per
month) and long-term (years) statistical analysis of magnetic fluxes
from whole sunspots and umbral areas, their locations and temporal
variations during the selected period. The comparison revealed a strong
north-south asymmetry in the identified sunspot and umbral magnetic
fluxes, which varies with the solar activity cycle. This research is
a part of the European Grid of Solar Observations (EGSO) project.
---------------------------------------------------------
Title: The AstroGrid Pilot Programme
Authors: Mann, R. G.; Davenhall, A. C.; Page, C. G.; Watson, M. G.;
Richards, A. M. S.; Garrington, S. T.; Holloway, A. J.; Bentley,
R. D.; Pike, C. D.; Perry, C. H.; Stamper, R.
2004tivo.conf..147M Altcode:
We describe the AstroGrid Pilot Programme, a set of testbeds conducted
during AstroGrid's one-year Phase A study, and intended to complement
the science requirements analysis and technology evaluations comprising
the remainder of the Phase A programme. We selected a pilot to address
an issue of particular relevance to each of AstroGrid's five broad
scientific areas, to allow empirical study of many aspects of the
general database federation problem and to engage, from the outset,
all parts of our user community. The lessons learnt during the course
of the Pilot Programme will help define the direction of AstroGrid's
Phase B implementation.
---------------------------------------------------------
Title: Integrated Access to Solar Data using EGSO
Authors: Bentley, R. D.; Csillaghy, A.; Scholl, I.; Vial, J. -C.;
Aboudarham, J.; Antonucci, E.; Zharkova, V. V.; Pike, C. D.
2004cosp...35.3935B Altcode: 2004cosp.meet.3935B
The European Grid of Solar Observations (EGSO) is a virtual observatory
based on Grid technology that will change the way users analyze solar
data. EGSO is funded under the IST (Information Society Technologies)
thematic priority of the European Commission's Fifth Framework Programme
(FP5). It started in March 2002 and will last for 3 years. The EGSO
Consortium comprises eleven groups from five countries in Europe
and the US, and is led by the Mullard Space Science Laboratory
of University College London. The project aims to overcome one of
the major hurdles in the analysis of solar data - finding what data
are available and retrieving those that are needed. EGSO is creating
layers of metadata catalogues that will for the first time provide the
ability to select solar data based on phenomena and events. It is also
integrating access to solar data by building a Grid including solar
archives around the world. This combination of metadata and tools for
selecting, processing and retrieving distributed and heterogeneous
solar data, will radically change the way that data are distributed
and analyzed. EGSO is collaborating closely with groups in the US who
are working on similar virtual observatory projects for the solar,
solar-terrestrial and heliospheric communities with the objective
of providing integrated access to these data. In particular, strong
synergies between the EGSO and CoSEC projects are producing innovative
ways of accessing the data that will be deployed in both projects. Since
the first release of EGSO in September 2003, members of the solar
community have been involved in product testing. The constant testing
and feedback allows us to continue to improve the quality and usability
of the system. The capabilities of the latest release (R4) will be
described, and the scientific problems that it addresses discussed.
---------------------------------------------------------
Title: Intelligent approach to the data analysis with the Solar
Feature Catalogues
Authors: Zharkova, V. V.; Aboudarham, J.; Ipson, S. S.; Bentley,
R. D.; Zharkov, S. I.; Benkhalil, A. K.; Fuller, N.
2004cosp...35.3488Z Altcode: 2004cosp.meet.3488Z
This paper presents searchable Solar Feature Catalogues developed
for the European Grid of Solar Observations using various image
processing and pattern recognition techniques. The techniques were
applied on solar images for automated detection of sunspots, active
regions, filaments and magnetic field on the Ca II K1, Ca II K3
and H<SUB>α</SUB> solar images from the Meudon Observatory and the
SOHO/MDI white light images and magnetograms. Using the recognised
parameters a structured database of the solar feature catalogues was
built on a mysql server for every feature and used for tracking of
a few active regions and associated with them magnetic field changes
produced many solar flares in October-November '03. We try to define
the key parameters for active region activity and relate them to the
parameters recognised with SFC for the future activity forecast. Some
samples of statistical analysis of sunspot areas and locations are
also presented and used for classification. The work is a part of the
project European Grid of Solar Observations. .
---------------------------------------------------------
Title: Intelligent approach to the data analysis with the Solar
Feature Catalogues
Authors: Zharkova, V. V.; Aboudarham, J.; Ipson, S. S.; Bentley,
R. D.; Zharkov, S. I.; Benkhalil, A. K.; Fuller, N.
2004cosp...35.3491Z Altcode: 2004cosp.meet.3491Z
This paper presents searchable Solar Feature Catalogues developed
for the European Grid of Solar Observations using various image
processing and pattern recognition techniques. The techniques were
applied on solar images for automated detection of sunspots, active
regions, filaments and magnetic field on the Ca II K1, Ca II K3 and
H<SUB>α</SUB> solar images from the Meudon Observatory and the SOHO/MDI
white light images and magnetograms. Using the recognised parameters
a structured database of the solar feature catalogues was built on
a mysql server for every feature and used for tracking of the active
regions 484 and 486 and associated with them magnetic field changes
produced many solar flares in October-November '03. We try to define
the key parameters for active region activity and relate them to the
parameters recognised with SFC for the future activity forecast. Some
samples of statistical analysis of sunspot areas and locations are
also presented and used for classification. The work is a part of the
project European Grid of Solar Observations.
---------------------------------------------------------
Title: Tracking of solar active regions and search for classification
parameters
Authors: Benkhalil, A.; Zharkova, V.; Bentley, R.; Zharkov, S.;
Ipson, S.
2004cosp...35.3125B Altcode: 2004cosp.meet.3125B
This paper presents the application of Solar Feature Catalogue (SFC)
created with an automated technique for active region detection from
SOHO/MDI, SOHO/EIT and Hα images from Meudon. The two active regions
(NOAA 484 and 486) producing many flares in October and November '03
were tracked during their lifetime on a solar disk in Hα and Fe XII,
195 Å wavelengths. These regions produced a large number of flares with
different significance including a few X-class flares. We investigate
their morphology and evaluation leading to a flare production and
compare these with the magnetic field changes before and during a
flare. In SFC each region is characterized by a number of physical and
photometric properties, which are stored in the database. These include:
the center of gravity in pixel and heliographic coordinates; minimum,
maximum and mean intensity within the active region; area in square
degrees and dimensions in pixels; contrast ratios; and a chain-code
representation of the active region boundary. Based on a comparison of
the active region parameters selected from the SFC with the magnetic
field configuration and strength we try to select the key parameters
defining a region activity in flare production that can be used for
a preliminary active region classification.
---------------------------------------------------------
Title: A full-disk image standardisation of the synoptic solar
observations at the Meudon Observatory
Authors: Zharkova, V. V.; Ipson, S. S.; Zharkov, S. I.; Benkhalil,
A.; Aboudarham, J.; Bentley, R. D.
2003SoPh..214...89Z Altcode:
Robust techniques are developed to put the Hα and Ca K line full-disk
images taken at the Meudon Observatory into a standardised form of a
`virtual solar image'. The techniques include limb fitting, removal
of geometrical distortion, centre position and size standardisation
and intensity normalisation. The limb fitting starts with an initial
estimate of the solar centre using raw 12-bit image data and then
applies a Canny edge-detection routine. Candidate edge points for the
limb are selected using a histogram based method and the chosen points
fitted to a quadratic function by minimising the algebraic distance
using SVD. The five parameters of the ellipse fitting the limb are
extracted from the quadratic function. These parameters are used to
define an affine transformation that transforms the image shape into a
circle. Transformed images are generated using the nearest neighbour,
bilinear or bicubic interpolation. Intensity renormalisation is also
required because of a limb darkening and other non-radial intensity
variations. It is achieved by fitting a background function in polar
coordinates to a set of sample points having the median intensities
and by standardising the average brightness. Representative examples
of intermediate and final processed results are presented in addition
to the algorithms developed. The research was done for the European
Grid of Solar Observations (EGSO) project.
---------------------------------------------------------
Title: Solar Feature Catalogue in the European Grid of Solar
Observations
Authors: Zharkova, V. V.; Ipson, S. S.; Bentley, R. D.; Aboudarham,
J.; Zharkov, S.; Benkhalil, A.; EGSO Team
2003SPD....34.0205Z Altcode: 2003BAAS...35..807Z
The first results in automated recognition of 4 different solar features
(sunspots, active regions, filaments, magnetic field neutral lines)
are presented. The problems associated with a digital image cleaning,
pattern recognition techniques applicable to different types of features
and their implementation in the Solar Feature Catalogues (SFCs) are
discussed. The preliminary results of a systematic investigation of
the selected features chosen from the SFCs and their correlations
with magnetic structures are presented. The research is done for the
European Grid of Solar Observations funded by the European Commission.
---------------------------------------------------------
Title: EGSO - Current Status and Expectations
Authors: Bentley, R. D.; EGSO 0
2003SPD....34.0204B Altcode: 2003BAAS...35..807B
EGSO, the European Grid of Solar Observations, is developing a data Grid
to provide enhanced access to solar data from around the globe. The
project, which is funded by the European Commission, is just over a
year old and it recently passed its first review. A working version of
the architectural design was recently completed and detailed work has
now started in earnest. <P />We will present details of the design,
how it will be implemented and the timescales for different part of
the project. Examples of services and interfaces already available
will be shown. <P />EGSO is working closely with the US Virtual Solar
Observatory (US-VSO) and the Sun-Earth Connector (CoSEC) and we are
trying to the projects compliment each other - a working group to
ensure this was recently formed. <P />For more details on EGSO see
our web site or contact the author.
---------------------------------------------------------
Title: First Steps to Solar Feature Catalogues
Authors: Zharkova, Valentina V.; Bentley, Robert D.; Ipson, Stanley S.;
Zharkov, Sergey I.; Benkhalil, Ali; Aboudarham, Jean; Fuller, Nicolas
2003IAUJD...7E..14Z Altcode:
The first results are presented for automated recognition of four
different features: sunspots active regions filaments and magnetic
field and their presentation in the feature catalogues. We discuss
problems with digital images standardisation and pattern recognition
techniques for different types of wavelengths. Possible application of
the feature catalogues for the Space Weather project is discussed. The
research was funded by the European Grid of Solar Observation project
IST 2001 32409 funded by the European Commission.
---------------------------------------------------------
Title: EGSO - the European Grid of Solar Observations
Authors: Bentley, Robert D.; EGSO Consortium
2002ESASP.506..923B Altcode: 2002ESPM...10..923B; 2002svco.conf..923B
The European Grid of Solar Obervations (EGSO) is a Grid testbed funded
by the European Commission under the Information Society Technologies
(IST) thematic priority of the Fifth Framework Programme (FP5). EGSO
will provide the tools and infrastructure needed to create a data grid
that will form the fabric of a virtual solar observatory. EGSO started
in March 2002 and will last for 36 months. The project involves eleven
groups from ten institutions located in five countries in Europe and
the US and is led by University College London. The EGSO Consortium
is in discussion with other groups interested in creating a virtual
observatory with the aim of finding a solution that is universally
acceptable.
---------------------------------------------------------
Title: EGSO in need for a global schema
Authors: Hill, Frank; Csillaghy, Andre; Bentley, Robert D.; Aboudarham,
Jean; Antonucci, Ester; Finkelstein, Anthony; Ciminiera, Luigi;
Gurman, Joseph B.; Scholl, Isabelle; Pike, Dave; Zharkova, Valentin
2002SPIE.4846...35H Altcode:
The European Grid of Solar Observations (EGSO) is a project to develop
a virtual observatory for the solar physics community. Like in all
such projects, a vital component is a schema that adequately describes
the data in the distributed data sets. Here, we discuss the schema in
general terms, and present a draft example of a portion of a possible
XML schema.
---------------------------------------------------------
Title: On a possible cause of discrepancy between Yohkoh and SMM
calcium abundance determinations in flares
Authors: Sylwester, J.; Kepa, A.; Bentley, R. D.
2002AdSpR..30..105S Altcode:
We have investigated problems concerning the discrepancy between
estimates of absolute calcium abundances (A <SUB>Ca</SUB>) in solar
flares as derived from soft X-ray high resolution spectra as obtained
from Yohkoh and Solar Maximum Mission ( SMM) Bragg spectrometers. The
analysis of these spectra allows for determination of absolute calcium
abundance since both Ca XIX resonance line and neighbouring continuum
are reliably measured in these experiments. The abundance determinations
are possible by means of fitting the synthetic spectra to the observed
ones. In previous work, we attributed part (around 50%) of the observed
disagreement to a possible instrumental problem in Yohkoh. In the
present research, we consider in more details possible causes of
the other part of the discrepancy. We first investigate whether the
estimates of (A <SUB>Ca</SUB>) depend substantially on the extension of
the observed short wavelength wing of the Ca XIX resonance line. This
problem is important in the case of the analysis of Yohkoh spectra,
since the extension of the spectrum towards the short wavelengths
depends on the position of the flare along North—South direction
on the Sun. After verifying the robustness of results of the spectral
fitting technique, we have considered possible physical scenario which
may cause the observed discrepancy. The hypothesis tested was that
the Ca abundance in flares is correlated with brightness in the source
— namely that it is a few times higher in the centre of the source
(flaring kernel) than outside. We have found that postulated model may
account for a part of the noted discrepancy as the SMM spectrometer
has been equipped with the 6 × 6 arcmin collimator and no collimator
has been used on Yohkoh.
---------------------------------------------------------
Title: The European Grid of Solar Observations (EGSO)
Authors: Bentley, R. D.; EGSO Team
2002AAS...200.5804B Altcode: 2002BAAS...34..740B
A major hurdles in the analysis of solar data is finding what data
are available and retrieving those that are needed. Planned space-
and ground-based instruments will produce huge volumes of data and
even taking into account the continuous technical advances, it is
clear that a new approach is needed to the way we use these data. The
European Grid of Solar Observations (EGSO) is a Grid test-bed that will
change the way users analyze solar data. EGSO will federate solar data
archives across Europe and beyond, and will create the tools to select,
process and retrieve distributed and heterogeneous solar data. It will
provide mechanisms to produce standardized observing catalogues for
space and ground-based observations, and the tools to create solar
feature catalogues that will facilitate the selection of solar data
based on features, events and phenomena. In essence, EGSO will provide
the fabric of a virtual observatory. EGSO is funded under the IST
(Information Society Technologies) thematic programme of European
Commission's Fifth Framework Programme (FP5). The project started in
March 2002 and will last for 3 years. The EGSO consortium comprises
10 institutes from Europe and the US, and is led by the Mullard Space
Science Laboratory (MSSL) of University College London (UCL). EGSO
plans to work closely with groups funded under NASA's Virtual Solar
Observatory (VSO) initiative, and with the team at Lockheed-Martin
who are doing similar work within the ILWS programme.
---------------------------------------------------------
Title: EGSO - the next step in data analysis
Authors: Bentley, Robert D.
2002ESASP.477..603B Altcode: 2002scsw.conf..603B
In April 2001, a proposal to create a grid of solar data archives
was submitted to the European Commission under the Information
Society Technologies (IST) program. The European Grid of Solar
Observations (EGSO) will provide the tools and infrastructure needed
to create the data grid that will form the fabric of a virtual
solar observatory. Every attempt will be made to ensure that EGSO is
universally acceptable. The EGSO proposal has been positively evaluated
and the project has been selected for negotiation. If successful,
the project will start in early 2002.
---------------------------------------------------------
Title: Monitoring cosmic radiation on aircraft
Authors: Bentley, Robert D.; Iles, R. H. A.; Jones, J. B. L.; Hunter,
R.; Taylor, G. C.; Thomas, D. J.
2002ESASP.477..535B Altcode: 2002scsw.conf..535B
The Earth is constantly bombarded by cosmic radiation that can be either
galactic or solar in origin. At aircraft altitudes, the radiation levels
are much higher than at sea level and recent European legislation has
classified aircrew as radiation workers. University College London is
working with Virgin Atlantic Airways on a 3 year project to monitor
the levels of cosmic radiation on long-haul flights. The study will
determine whether models currently used to predict radiation exposure
of aircrew are adequate. It will also try to determine whether solar
flare activity can cause significant enhancement to the predicted doses.
---------------------------------------------------------
Title: Early results from RESIK and Diogeness soft X-ray spectrometers
aboard Coronas-F satellite
Authors: Sylwester, Janusz; Gaicki, Ireneusz; Kordylewski, Zbigniew;
Kowalinski, Miroslaw; Nowak, Stanislaw; Plocieniak, Stefan; Trzebinski,
Witold; Bentley, Robert D.; Whyndham, Matt; Lang, Jim; Brown, Charles;
Farnik, Frantisek; Oraevsky, Victor N.; Stepanov, Anatolyi; Lisin,
Dimitry
2002ESASP.477..597S Altcode: 2002scsw.conf..597S
We present examples of early, unreduced results obtained from
the instrument package dedicated for spectroscopic studies of
coronal flaring plasma composition. The package consists of two
Bragg spectrometers, RESIK and Diogeness. These instruments have
been launched aboard the Russian Coronas-F solar observatory on 31
July 2001. The data being received from these two spectrometers allow
for determining the absolute abundances of several important elements
including that of low and high first ionization potential (FIP). Based
on the data which have been (and hopefully will be) obtained, we will
investigate fast temporal variations (~1 min) of the plasma composition
in flares and hotter active regions. The analysis of spectra obtained
will certainly allow for spectroscopic studies of several, so-called
"triplet" lines forming in He-like, highly ionized plasma since the
spectra received are apparently of unprecedented quality. The Coronas-F
Mission is expected to be supported for at least two years.
---------------------------------------------------------
Title: Space weather effects and commerical airlines
Authors: Jones, J.; Bentley, R.; Hunter, R.; Taylor, G.; Thomas, D.
2002cosp...34E3042J Altcode: 2002cosp.meetE3042J
Space Weather (SW) phenomena can effect many areas of commercial
airline operations including avionics, communications and GPS
navigation systems. Of particular importance at present is the recently
introduced EU legislation requiring the monitoring of aircrew radiation
exposure, including any variations at aircraft altitudes due to solar
activity. The Mullard Space Science Laboratory is collaborating with
Virgin Atlantic Airways, the Civil Aviation Authority and the National
Physical Laboratory on a 3- year project to monitor the levels of
cosmic radiation on long-haul flights. The study will determine
whether computer models currently used to predict radiation exposure
of aircrew are adequate. It also aims to determine whether solar
or geomagnetic activity can cause significant modifications to the
doses. This presentation will begin by showing some of the preliminary
results obtained so far. As an example, we present a comparison of
flight doses measured following the 14t h July 2000 X - class flare
that was accompanied by a major Solar Particle Event (SPE). The
results highlight the importance of a range of external factors
that can strongly influence how SPEs may effect the measured dose at
aircraft altitudes. At present, any SPE contributions in the airlines'
dose records can only be poorly estimated retrospectively. Ideally,
it would be better to try to avoid operating during these possibly
significant radiation - enhancing events by utilising SW information
(alerts, warnings, etc.). However, doing so poses many difficult
operational problems for such a heavily regulated international
industry, in terms of safety, security and procedures. Therefore,
the use of timely SW information, which is still very unreliable, in
a similar manner to terrestrial weather will require agreement from
the International Civil Aviation Organisation (ICAO) and International
Air Transport Association (IATA) to Air Traffic Control and Aviation
Regulatory Authority's. This presentation will, therefore, conclude by
summarising some of the identified key issues, which must be addressed,
with the help of the science community, if the airlines want to benefit
from the availability of Space Weather Services.
---------------------------------------------------------
Title: The European Grid of Solar Observations (EGSO)
Authors: Bentley, R. D.
2001AGUFMSH31B0713B Altcode:
Access to solar data is becoming an increasing problem. Although
the Internet has made it much easier to share data, the volume and
complexity of the data are increasing rapidly, and it is often difficult
to identify datasets of interest, and then locate and retrieve them. In
April 2001, a proposal to create a Grid of solar data archives was
submitted to the European Commission under the Information Society
Technologies (IST) program. The European Grid of Solar Observations
(EGSO) will provide the tools and infrastructure needed to create the
data grid that will form the fabric of a virtual solar observatory. EGSO
will allow a user to identify solar observations covering a given
time interval, active region, or type of feature; it will locate
the selected observation and then return them after any necessary
pre-processing; it will also provide the facility of analyze large
volumes of data at the data source. The EGSO consortium comprises 10
groups in Europe and the US, including experts in both solar data and
IT. The project has been positively evaluated and has been selected
for negotiations. Inputs from the solar community are now needed in
order to formulate the details of the project.
---------------------------------------------------------
Title: Preface
Authors: Culhane, J. L.; Bentley, R. D.; Doyle, G.
2001AdSpR..26.1711C Altcode:
No abstract at ADS
---------------------------------------------------------
Title: SolarSoft
Authors: Freeland, S.; Bentley, R.
2000eaa..bookE3390F Altcode:
The SolarSoft system (SSW) is a set of integrated software libraries,
databases, and system utilities which provide a common programming
and data analysis environment for solar physics. The SolarSoft
environment provides a consistent look and feel at widely distributed
co-investigator institutions to facilitate data exchange and to
stimulate coordinated analysis. Commonalities and overlap in sola...
---------------------------------------------------------
Title: Magnetic Activity Associated With Radio Noise Storms
Authors: Bentley, R. D.; Klein, K. -L.; van Driel-Gesztelyi, L.;
Démoulin, P.; Trottet, G.; Tassetto, P.; Marty, G.
2000SoPh..193..227B Altcode:
As it crossed the solar disk in May and June 1998, AR 8227 was tracked
by TRACE, Yohkoh, SOHO, and many ground-based observatories. We have
studied how the evolution of the magnetic field resulted in changes in
activity in the corona. In particular, we examine how the evolving field
may have led to the acceleration of electrons which emit noise storms
observed by the Nançay Radio Heliograph between 30 May and 1 June
1998, in the absence of any flare. The magnetic changes were related
to moving magnetic features (MMFs) in the vicinity of the leading
spot and are related to the decay of this spot. Within the limits of
the instrumental capabilities, the location in time and space of the
radio emissions followed the changes observed in the photospheric
magnetograms. We have extrapolated the photospheric magnetic field
with a linear force-free approximation and find that the active region
magnetic field was very close to being potential. These computations
show a complex magnetic topology associated to the MMFs. The observed
photospheric evolution is expected to drive magnetic reconnection in
such complex magnetic topology. We therefore propose that the MMFs
are at the origin of the observed metric noise-storms.
---------------------------------------------------------
Title: Influence of Yohkoh BCS Instrumental Shape on Results of
Spectral Fitting in Vicinity of Ca XIX Lines
Authors: Kepa, A.; Sylwester, J.; Bentley, R. D.
1999ESASP.448..835K Altcode: 1999ESPM....9..835K; 1999mfsp.conf..835K
No abstract at ADS
---------------------------------------------------------
Title: Microwave, Soft and Hard X-Ray Observations of Solar Flares -
a Self-Consistent Model of the Flare Site
Authors: Chiuderi Drago, F.; Alissandrakis, C. E.; Bentley, R. D.;
Philips, A. T.
1998SoPh..182..459C Altcode:
High-resolution microwave observations of several flares performed
with the Westerbork Synthesis Radio Telescope (WRST) on 3 and 4 July
1993 are compared with Yohkoh observations in the soft and hard X-ray
domain. Only for one flare, among the six analyzed, was the hard
X-ray spectrum between 20 and 200 keV available from the Wide Bragg
Spectrometer, supplying the energy spectrum of non-thermal particles
responsible for this radiation and for the radio emission. A complete
model of this flare is derived which accounts for all available
observations in the X-ray and radio wavelengths.
---------------------------------------------------------
Title: Detailed Evidence for Flare-to-Flare Variations of the Coronal
Calcium Abundance
Authors: Sylwester, J.; Lemen, J. R.; Bentley, R. D.; Fludra, A.;
Zolcinski, M. -C.
1998ApJ...501..397S Altcode:
The analysis of X-ray solar flare spectra obtained by the Bent
Crystal Spectrometer on board the Solar Maximum Mission satellite is
presented. The ratio of the Ca XIX resonance line intensity to the
nearby continuum is used to measure the calcium abundance relative to
hydrogen (A<SUB>Ca</SUB>). A description of the spectroscopic method
of determining the absolute calcium abundance is given. Possible
instrumental and solar effects that might influence the abundance
estimates are evaluated. Over 5000 spectra from more than 100 flares are
analyzed. We find a flare-to-flare variation for A<SUB>Ca</SUB> that is
not correlated with flare size, Hα importance, or with several other
flare characteristics. For flares observed from two active regions, the
observed value of A<SUB>Ca</SUB> increases as a function of time. The
average for all flares is <A<SUB>Ca</SUB>> = (5.77 +/- 1.41) ×
10<SUP>-6</SUP>. A discussion of investigated correlations of derived
A<SUB>Ca</SUB> values with several flare characteristics is presented.
---------------------------------------------------------
Title: What YOHKOH has Discovered about Active Regions
Authors: Bentley, R. D.
1998ASPC..155..176B Altcode: 1998sasp.conf..176B
No abstract at ADS
---------------------------------------------------------
Title: Joint Observations and an Active Region with SOHO and YOHKOH
Authors: Bentley, R. D.
1998ASSL..229..251B Altcode: 1998opaf.conf..251B
No abstract at ADS
---------------------------------------------------------
Title: Iron and calcium abundances in solar flares from the
multitemperature analysis of X-ray spectra (abstract)
Authors: Fludra, A.; Bentley, R. D.; Culhane, J. L.; Lemen, J. R.;
Sylwester, J.
1998PAICz..88...91F Altcode:
No abstract at ADS
---------------------------------------------------------
Title: YOHKOH Bragg Crystal Spectrometer Light Curves for S XV
(5.0163 - 5.1143 Angstroms)
Authors: Mariska, John T.; Bentley, R. D.; Pike, C. D.
1997STIN...9838248M Altcode:
This memorandum report summarizes the data produced during the sixth
year of operation by the Bragg Crystal Spectrometer (BCS) on the Yohkoh
spacecraft. Each page shows the total count rate in the S XV channel
of the BCS for a single day. This channel nominally observes the Sun
in the wavelength range from 5.0163 - 5.1143 Angstroms. These plots
are useful for identifying flare data for further analysis and for
determining the data file name and tape number that contains the data.
---------------------------------------------------------
Title: The Whole Sun Catalogue
Authors: Sanchez Duarte, L.; Fleck, B.; Bentley, R.
1997ASPC..118..382S Altcode: 1997fasp.conf..382S
To maximize the scientific outcome of the wealth of solar observations
available, it would be extremely useful to have a complete, central
catalogue giving some basic information such as `where, when, what'
about all solar observations made. This paper presents a proposal
for such a catalogue based on the infrastructure developed for the
SOHO Archive, but being independent of it. Our goal is to refine this
proposal with the help of the JOSO group and to implement it by 1997.
---------------------------------------------------------
Title: Diagnostics of Energy Release in the X-Ray Corona
Authors: Bentley, Robert D.
1997LNP...483....3B Altcode: 1997cprs.conf....3B
Energy is released in the corona in many different forms. In this
paper we discuss phenomena that are observed in X-rays in flares
and sub-flares. Recent results of X-ray bright-points, transient
brightenings and jets are reviewed, and diagnostics that result from
bulk plasma motions are discussed. Finally, three events are examined
in detail and the implications of the observation discussed in relation
to flare models.
---------------------------------------------------------
Title: Calcium abundance measurements using the Yohkoh BCS
Authors: Bentley, R. D.; Sylwester, J.; Lemen, J. R.
1997AdSpR..20.2275B Altcode:
Soft X-ray observations by SMM and other spacecraft have shown
that the abundance of certain elements in solar corona varies from
flare to flare. In this study, observations made by the Yohkoh Bragg
Crystal Spectrometer (BCS) in helium-like Ca XIX have been analysed,
and Ca abundance determined for 177 flares observed during the first
four years of the mission (1991-1995). The average abundance of Ca
relative to H for all flares is < A_Ca > = (3.64 +/- 0.39) x
10^-6. As with an earlier study of SMM data, the abundance is found to
be enhanced compared to the photosphere ((2.24 +/- 0.10) x 10^-6), and
with only minor variation from flare to flare. However, the absolute
value and range of values determined by this study is smaller than in
the previous study; these differences are discussed.
---------------------------------------------------------
Title: Hard and Soft X-Ray Observations of Solar Limb Flares
Authors: Mariska, John T.; Sakao, T.; Bentley, R. D.
1996ApJ...459..815M Altcode:
Using observations from the Yohkoh Bragg Crystal Spectrometer, hard
X-ray telescope, and soft X-ray telescope, we have examined eight limb
flares. Four of the flares have the footpoints occulted by the solar
limb. We find that the occulted flares generally have softer hard
X-ray spectra and smaller peak values of the nonthermal broadening
velocity than nonocculted flares. All other physical parameters show
no differences between occulted flares and nonocculted flares. The
hard X-ray spectra support a model in which the footpoint emission
is due to thick-target sources, while the looptop emission is due to
thin-target sources. High spectral resolution hard X-ray observations
should thus show a break in the hard X-ray spectrum of the looptop
source. We can find no obvious explanation for the differences in
nonthermal broadening velocity.
---------------------------------------------------------
Title: Timing of the soft X-ray blue-wing and the hard X-ray burst
from observations by YOHKOH
Authors: Bentley, R. D.; Doschek, G. A.; Mariska, J. T.
1996AdSpR..17d..55B Altcode: 1996AdSpR..17...55B
A knowledge of the relative timing of the hard X-ray burst and emission
in soft X-rays is helpful in deciding between a number of theoretical
models that describe the mechanism of a solar flare. Here we continue
a study of this relationship using observations from the Yohkoh Bragg
Crystal Spectrometer and Hard X-ray Telescope, together with supporting
observations from the CGRO Batse experiment. The enhanced capabilities
of the instruments onboard Yohkoh have made it possible to study the
problem in a way that was not previously possible. A study of the
timing, intensity and evolution of the soft X-ray blue-wing shows that
there is no simple relationship between hard and soft X-ray emissions;
strong blue-wings sometimes result from relatively weak hard X-ray
bursts; the burst responsible for the blue wing need not be the first
or most intense burst associated with the flare; the blue-wing is found
to follow very closely after the hard X-ray burst. We also discuss
timing issues and why other researchers may have reached different
conclusions on this matter.
---------------------------------------------------------
Title: Magnetic Reconnection in the Solar Atmosphere
Authors: Bentley, R. D.; Mariska, J. T.
1996ASPC..111.....B Altcode: 1997ASPC..111.....B
The following topics were dealt with: bright points, jets, emerging
flux, coronal heating, flare observations, flare theory, larger
structures and coronal ejections.
---------------------------------------------------------
Title: YOHKOH observations of solar limb flares
Authors: Bentley, R. D.; Mariska, J. T.; Sakao, T.
1996ASPC..109..107B Altcode: 1996csss....9..107B
No abstract at ADS
---------------------------------------------------------
Title: Mass Motions in Flares
Authors: Bentley, R. D.
1996mpsa.conf..177B Altcode: 1996IAUCo.153..177B
No abstract at ADS
---------------------------------------------------------
Title: Hard and Soft X-ray Observations of Solar Limb Flares
Authors: Mariska, J. T.; Sakao, T.; Bentley, R. D.
1996mpsa.conf..523M Altcode: 1996IAUCo.153..523M
No abstract at ADS
---------------------------------------------------------
Title: Temperature Structure of Active Regions Deduced from the
Helium-Like Sulphur Lines
Authors: Watanabe, Tetsuya; Haka, Hirohisa; Shimizu, Toshifumi; Hiei,
Eijiro; Bentley, Robert D.; Lang, James; Phillips, Kenneth J. H.; David
Pike, C.; Fludra, Andrzej; Bromage, Barbara J. I.; Mariska, John T.
1995SoPh..157..169W Altcode:
Solar active-region temperatures have been determined from the full-Sun
spectra of helium-like sulphur (SXV) observed by the Bragg Crystal
Spectrometer on board theYohkoh satellite. The average temperature
deduced from SXV is demonstrated to vary with the solar activity level:
A temperature of 2.5 × 10<SUP>6</SUP> K is derived from the spectra
taken during low solar activity, similar to the general corona, while
4 × 10<SUP>6</SUP> K is obtained during a higher activity phase. For
the latter, the high-temperature tail of the differential emission
measure of active regions is found most likely due to the superposition
of numerous flare-like events (micro/nano-flares).
---------------------------------------------------------
Title: Hard and Soft X-Ray Observations of Solar Limb Flares
Authors: Mariska, J. T.; Sakao, T.; Bentley, R. D.
1995SPD....26.1312M Altcode: 1995BAAS...27..989M
No abstract at ADS
---------------------------------------------------------
Title: Hydra — A 3-dimensional electron and ion hot plasma
instrument for the POLAR spacecraft of the GGS mission
Authors: Scudder, J.; Hunsacker, F.; Miller, G.; Lobell, J.;
Zawistowski, T.; Ogilvie, K.; Keller, J.; Chornay, D.; Herrero, F.;
Fitzenreiter, R.; Fairfield, D.; Needell, J.; Bodet, D.; Googins,
J.; Kletzing, C.; Torbert, R.; Vandiver, J.; Bentley, R.; Fillius,
W.; McIlwain, C.; Whipple, E.; Korth, A.
1995SSRv...71..459S Altcode:
HYDRA is an experimental hot plasma investigation for the POLAR
spacecraft of the GGS program. A consortium of institutions has
designed a suite of particle analyzers that sample the velocity space
of electron and ions between ≃2 keV/q 35 keV/q in three dimensions,
with a routine time resolution of 0.5 s. Routine coverage of velocity
space will be accomplished with an angular homogeneity assumption of
≃16°, appropriate for subsonic plasmas, but with special ≃1.5°
resolution for electrons with energies between 100 eV and 10 keV along
and opposed to the local magnetic field. This instrument produces 4.9
kilobits s<SUP>-1</SUP> to the telemetry, consumes on average 14 W and
requires 18.7 kg for deployment including its internal shielding. The
scientific objectives for the polar magnetosphere fall into four broad
categories: (1) those to define the ambient kinetic regimes of ions and
electrons; (2) those to elucidate the magnetohydrodynamic responses
in these regimes; (3) those to assess the particle populations with
high time resolution; and (4) those to determine the global topology
of the magnetic field. In thefirst group are issues of identifying the
origins of particles at high magnetic latitudes, their energization,
the altitude dependence of the forces, including parallel electric
fields they have traversed. In thesecond group are the physics of the
fluid flows, regimes of current, and plasma depletion zones during
quiescent and disturbed magnetic conditions. In thethird group is the
exploration of the processes that accompany the rapid time variations
known to occur in the auroral zone, cusp and entry layers as they
affect the flow of mass, momentum and energy in the auroral region. In
thefourth class of objectives are studies in conjunction with the SWE
measurements of the Strahl in the solar wind that exploit the small
gyroradius of thermal electrons to detect those magnetic field lines
that penetrate the auroral region that are directly ‘open’ to
interplanetary space where, for example, the Polar Rain is observed.
---------------------------------------------------------
Title: YOHKOH Bragg Crystal Spectrometer light curves for CA 29(3.1633
- 3.1933 A): 1 October 1993 - 30 September 1994
Authors: Mariska, John T.; Bentley, R. D.; Pike, C. D.
1994YBCSCrept.....M Altcode:
This memorandum report summarizes the data produced during the third
year of operation by the Bragg Crystal Spectrometer (BCS) on the Yohkoh
spacecraft. Each page shows the total count rate in the Ca XIX channel
of the BCS for a single day. This channel nominally observes the Sun in
the wavelength range from 3.1633 to 3.1933 A. These plots are useful
for identifying flare data for further analysis and for determining
the data file name and tape name that contains the data.
---------------------------------------------------------
Title: Yohkoh observations of the creation of high-temperature plasma
in the flare of 16 December 1991
Authors: Culhane, J. L.; Phillips, A. T.; Inda-Koide, M.; Kosugi,
T.; Fludra, A.; Kurokawa, H.; Makishima, K.; Pike, C. D.; Sakao, T.;
Sakurai, T.; Doschek, G. A.; Bentley, R. D.
1994SoPh..153..307C Altcode:
Yohkoh observations of an impulsive solar flare which occurred on 16
December, 1991 are presented. This flare was a GOES M2.7 class event
with a simple morphology indicative of a single flaring loop. X-ray
images were taken with the Hard X-ray Telescope (HXT) and soft X-ray
spectra were obtained with the Bragg Crystal Spectrometer (BCS)
on board the satellite. The spectrometer observations were made at
high sensivity from the earliest stages of the flare, are continued
throughout the rise and decay phases, and indicate extremely strong
blueshifts, which account for the majority of emission in CaXIX during
the initial phase of the flare. The data are compared with observations
from other space and ground-based instruments. A balance calculation
is performed which indicates that the energy contained in non-thermal
electrons is sufficient to explain the high temperature plasma which
fills the loop. The cooling of this plasma by thermal conduction
is independently verified in a manner which indicates that the loop
filling factor is close to 100%. The production of `superhot' plasma
in impulsive events is shown to differ in detail from the morphology
and mechanisms appropriate for more gradual events.
---------------------------------------------------------
Title: The 1991 November 9 Flare at 03.2 UT: Observations from YOHKOH
Authors: Doschek, G. A.; Mariska, J. T.; Strong, K. T.; Bentley, R. D.;
Brown, C. M.; Culhane, J. L.; Lang, J.; Sterling, A. C.; Watanabe, T.
1994ApJ...431..888D Altcode:
We discuss X-ray spectra and soft X-ray images of an M1.9 flare that
occurred on 1991 November 9 near 03.2 UT. These data were obtained with
instrumentation on the Japanese Yohkoh spacecraft. They cover the entire
rise phase and peak flare emission, and the beginning of the decay
phase. We determine the dynamics, temperature, and emission measure
of the flare as inferred from the X-ray line profiles of resonance
lines of Fe XXV, Ca XIX, and S XV. We discuss the morphology of the
flare as inferred from the soft X-ray images. The November 9 flare is
atypical in that a stronger than usual blueshifted emission component
(relative to the stationary component) is observed for the resonance
lines at flare onset. We discuss several methods for deconvolving the
blueshifted component from the stationary component. The X-ray line
profiles are consistent with predictions of numerical simulations
of chromospheric evaporation. The X-ray images reveal a flare with a
complicated loop geometry that is not fully understood. Many of the
features in the images are moving upwards at speeds ranging from a
few km/s to about 800 km/s. The blueshifted emission begins near the
onset of hard X-ray emission, implying that particle acceleration and
upflowing plasma have a common energy source.
---------------------------------------------------------
Title: The Correlation of Solar Flare Hard X-Ray Bursts with Doppler
Blueshifted Soft X-Ray Flare Emission
Authors: Bentley, R. D.; Doschek, G. A.; Simnett, G. M.; Rilee, M. L.;
Mariska, J. T.; Culhane, J. L.; Kosugi, T.; Watanabe, T.
1994ApJ...421L..55B Altcode:
We have investigated the temporal correlation between hard X-ray
bursts and the intensity of Doppler blueshifted soft X-ray spectral
line emission. We find a strong correlation for many events that have
intense blueshifted spectral signatures and some correlation in events
with modest blueshifts. The onset of hard X-rays frequently coincides to
within a few seconds with the onset of blueshifted emission. The peak
intensity of blueshifted emission is frequently close in time to the
peak of the hard X-ray emission. Decay rates of the blueshifted and hard
X-ray emission are similar, with the decay of the blueshifted emission
tending to lag behind the hard X-ray emission in some cases. There
are, however, exceptions to these conclusions, and, therefore, the
results should not be generalized to all flares. Most of the data for
this work were obtained from instruments flown on the Japanese Yohkoh
solar spacecraft.
---------------------------------------------------------
Title: Dynamics of a Low Energetic Solar Flare
Authors: Doyle, J. G.; Fludra, A.; Bentley, R. D.; Culhane, J. L.;
Metcalf, T.; Lemen, J. R.; Kosugi, T.
1994ASPC...64..402D Altcode: 1994csss....8..402D
No abstract at ADS
---------------------------------------------------------
Title: Yohkoh Observations from the Onset of Several Flares
Authors: Bentley, R. D.; YOHKOH Team
1994ddpn.conf..435B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The Relationship Between the Soft X-Ray Blue Wing and the
Hard X-Ray Burst
Authors: Bentley, R. D.
1994xspy.conf...87B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The Yohkoh mission: Instruments and recent results
Authors: Bentley, R. D.; YOHKOH Team
1994LNP...432..311B Altcode: 1994LNPM...11..311B
The Yohkoh spacecraft was launched on 30 August, 1991 by the Japanese
Institute of Space and Astronautical Science. The instruments, which
include hard and soft X-ray imaging telescopes, a Bragg spectrometer and
wide band full sun spectrometers, (which cover the energy range 2 kev to
10 MeV), were described. Results obtained from these instruments were
presented with special emphasis on data from the soft X-ray telescope
which views the Sun in the 0.2 - 3 keV range with an angular resolution
of 2.5 arc sec. Videos made from SXT datas were also presented at
the meeting.
---------------------------------------------------------
Title: Temperature Structure of Active Regions Deduced from the
Helium-Like Sulphur Lines
Authors: Watanabe, T.; Hara, H.; Shimizu, T.; Hiei, E.; Mariska,
J. T.; Bentley, R. D.; Fludra, A.; Lang, J.; Phillips, K. J. H.;
Pike, C. D.; Bromage, B. J. I.
1994xspy.conf...55W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Flare Plasma Dynamics Observed with the YOHKOH Bragg Crystal
Spectrometer. I. Properties of the CA XIX Resonance Line
Authors: Mariska, John T.; Doschek, G. A.; Bentley, R. D.
1993ApJ...419..418M Altcode:
Using data from the Bragg crystal spectrometer on the Yohkoh spacecraft
we have computed measures of the total intensity, centroid position,
and line width for the resonance line of Ca xix during the rise phase
and after maximum for 219 solar flares. The difference between the
centroid positions early and late in each flare yields a measure
of the line-of-sight velocity shift of the line centroid. We find
a trend in the average value of the centroid shift with distance
from Sun center suggesting radial mass motions with a characteristic
velocity of 58 km s<SUP>-1</SUP>. There is a correlation between the
rise-phase line widths and the centroid shift. We find no correlation
between the centroid shift and the peak intensity, rise time, and
total flare duration; and no correlation between the line width and
the distance from Sun center, the peak intensity, rise time, and total
flare duration. These results do not conclusively support or refute
the simple electron-beam-driven model or the thermal model for the
rise phase of a solar flare.
---------------------------------------------------------
Title: The 1992 January 5 Flare at 13.3 UT: Observations from YOHKOH
Authors: Doschek, G. A.; Strong, K. T.; Bentley, R. D.; Brown, C. M.;
Culhane, J. L.; Fludra, A.; Hiei, E.; Lang, J.; Mariska, J. T.;
Phillips, K. J. H.; Pike, C. D.; Sterling, A. C.; Watanabe, T.; Acton,
L. W.; Bruner, M. E.; Hirayama, T.; Tsuneta, S.; Rolli, E.; Kosugi,
T.; Yoshimori, M.; Hudson, H. S.; Metcalf, T. R.; Wuelser, J. -P.;
Uchida, Y.; Ogawara, Y.
1993ApJ...416..845D Altcode:
We discuss X-ray spectra and soft X-ray images of an M1.9 flare that
occurred on 1992 January 5 near 13.3 UT. These data were obtained
with instrumentation on the Japanese Yohkoh spacecraft. They cover
the entire rise phase of the flare. To supplement these data we have
ground-based magnetograms and Hα spectroheliograms. We calculate
the electron temperature and emission measure of the flare as a
function of time during the early rise phase using X-ray spectral
line intensities and line ratios. Using spectral line widths, line
profile asymmetries, and wavelength shifts due to the Doppler effect,
we calculate the dynamical properties of the flare. The time development
of the morphology of the flare, as revealed by the soft X-ray images
and the Hα spectroheliograms, and the physical quantities inferred
from the X-ray spectra, are compared with chromospheric evaporation
models. There is an enhancement of blueshifted emission that is closely
correlated with the hard X-ray bursts. Heating of one loop in the flare
is consistent with a conduction-evaporation model, but heating is found
in several structures that do not appear to be physically associated
with each other. No standard evaporation model can adequately explain
all of the observations.
---------------------------------------------------------
Title: Yohkoh observations of plasma upflows during solar flares
Authors: Culhane, J. L.; Phillips, A. T.; Pike, C. D.; Fludra, A.;
Bentley, R. D.; Bromage, B.; Doschek, G. A.; Hiei, E.; Inda, M.;
Mariska, J. T.; Phillips, K. J. H.; Sterling, A. C.; Watanabe, T.
1993AdSpR..13i.303C Altcode: 1993AdSpR..13..303C
Observations of two flares, an M 2.2 event on 16 December, 1991 and the
precursor to an X1 flare on 15 November, 1991 are presented. Spectra
obtained with the Bragg Crystal Spectrometer (BCS) are compared with
data from the Hard and Soft X-ray Telescopes (HXT, SXT) and the Wide
Band Spectrometer (WBS) on the satellite. For both events the creation
of upflowing plasma is detected. While the first event seems to conform
well to the chromospheric evaporation model for high temperature plasma
production, the behaviour for the second event is more complex.
---------------------------------------------------------
Title: Determination of coronal abundances of sulphur, calcium and
iron using the yohkoh bragg crystal spectrometer
Authors: Fludra, A.; Culhane, J. L.; Bentley, R. D.; Doschek, G. A.;
Hiei, E.; Phillips, K. J. H.; Sterling, A.; Watanabe, T.
1993AdSpR..13i.395F Altcode: 1993AdSpR..13..395F
Using spectra from the Bragg Crystal Spectrometer on Yohkoh we have
derived coronal abundances of sulphur, calcium and iron during several
flares from the ratio of the flux in the resonance line to the nearby
continuum. Multi-thermal effects have been taken into account using
differential emission measure analysis. We have also determined the
abundance of S in cool active regions during a period of very low solar
activity. We compare the coronal abundances of S, Ca and Fe with their
photospheric values.
---------------------------------------------------------
Title: Flare Plasma Dynamics Observed with the Yohkoh Bragg Crystal
Spectrometer
Authors: Mariska, J. T.; Doschek, G. A.; Bentley, R. D.
1993BAAS...25Q1178M Altcode:
No abstract at ADS
---------------------------------------------------------
Title: A Comparison of Solar Flare Hard X-Ray Bursts with Doppler
Blue-Shifted Soft X-Ray Emission
Authors: Rilee, M. L.; Bentley, R. D.; Culhane, J. L.; Doschek, G. A.;
Mariska, J. T.; Simnett, G. M.; Watanabe, T.
1993BAAS...25.1189R Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The Yohkoh Software and Database System
Authors: Morrison, M. D.; Freeland, S. L.; Lemen, J. R.; Acton, L. W.;
Bentley, R. D.
1993BAAS...25R1188M Altcode:
No abstract at ADS
---------------------------------------------------------
Title: YOHKOH Bragg Crystal Spectrometer light curves for CA XIX
(3.1631-3.1912A): 1 October 1991 - 30 September 1992
Authors: Mariska, John T.; Bentley, R. D.; Pike, C. D.
1993YBCSCrept.....M Altcode:
This Memo Report summarizes the data produced during the first year
of operation by the Bragg Crystal Spectrometer (BCS) on the Yohkoh
spacecraft. Each page shows the total count rate in the Ca XIX channel
of the BCS for a single day. This channel nominally observes the Sun in
the wavelength range from 3.1631 to 3.1912 A. These plots are useful
for identifying flare data for further analysis and for determining
the data file name and tape name that contain the data.
---------------------------------------------------------
Title: Dynamics of flaring loops. III - Interpretation of flare
evolution in the emission measure-temperature diagram
Authors: Sylwester, B.; Sylwester, J.; Serio, S.; Reale, F.; Bentley,
R. D.; Fludra, A.
1993A&A...267..586S Altcode:
The aim of the paper is to illustrate the application of the
density-temperature diagrams discussed by Jakimiec (1992) to
interpretation of soft X-ray measurements, namely, calcium spectra
recorded by the Solar Maximum Mission Bent Crystal Spectrometer. Using
the emission measure and the temperature values derived for a set
of hydrodynamic flare models discussed in previous papers, we have
obtained and analyzed the (sq rt epsilon-T) counterparts of the (N-T)
diagrams. Inspection of these diagrams reveals that they qualitatively
resemble the (N-T) diagrams. The inclinations of the decay trajectories
make the main difference. Next, we have performed a comparison of the
modeled and observed flare evolutionary trajectories. This comparison
allowed us to identify characteristic cases of evolution during the
decay phase. We have discussed time variations of the heating rate
for selected observed flares. The results of this paper illustrate
how to use the diagnostic diagrams in the interpretation of flare soft
X-ray measurements.
---------------------------------------------------------
Title: Determination of element abundances using the Yohkoh Bragg
Crystal Spectrometer.
Authors: Fludra, A.; Culhane, J. L.; Bentley, R. D.; Doschek, G. A.;
Hiei, E.; Phillips, K. J. H.; Sterling, A.; Watanabe, T.
1993uxrs.conf..542F Altcode: 1993uxsa.conf..542F
No abstract at ADS
---------------------------------------------------------
Title: Objectives of RESIK solar concave soft X-ray spectrometer
for CORONAS-F mission.
Authors: Sylwester, Janusz; Bentley, R. D.
1992ESASP.348..357S Altcode: 1992cscl.work..357S
Several institutes are involved in construction of the high sensitivity
soft X-ray spectrometer RESIK, to be flown aboard the Russian CORONAS-F
satellite in 1994/95. The scientific objectives of the instrument are
discussed, arising as a compromise between the scientific interests and
constrained by good quality large area crystals obtainable, detector
dimensions and the geometry of Bragg concave crystal reflection. Four
bands have been selected to perform measurements of the solar active
region and flare spectra: 2.97 - 3.24 Å, 3.15 - 3.25 Å, 4.95 - 5.15
Å, and 6.50 - 7.19 Å. Special "Dopplerometer" arrangement of the
crystals will allow to assign "absolute" wavelength scale and determine
the role of directed and turbulent flows in the source. Interpretation
of the line and continuum intensities will permit to derive the
differential emission measure for plasma temperatures T > 3MK, and
to determine the composition (relative to H) of the coronal plasma for
many elements including these with different first ionization potential.
---------------------------------------------------------
Title: Helium-Like Sulphur Emission Lines in Solar Active Regions
and Their Sub-C Class Variability
Authors: Watanabe, Tetsuya; Hiei, Eijiro; Lang, James; Culhane,
J. Leonard; Bentley, Robert D.; Doschek, George A.; Bromage, Barbara
J. I.; Brown, Charles M.; Feldman, Uri; Fludra, Andrzej; Kato, Takako;
Payne, Jeffrey
1992PASJ...44L.141W Altcode:
Helium-like sulphur spectra (formation temperature, T_m ~ 18times
10(6) K) from coronal active regions are being obtained by the Bragg
Crystal Spectrometer onboard the Yohkoh mission. The average electron
temperatures of the quiescent active regions deduced from the full-disk
integrated sulphur spectra are 3.5--4 times 10(6) K. The temporal
behavior of the emission lines in the sub-C level events shows that
hot plasmas (T > 10(7) K) can be produced in these weak events.
---------------------------------------------------------
Title: Observations of Several Small Flares with the Bragg Crystal
Spectrometer on YOHKOH
Authors: Culhane, J. Leonard; Fludra, Andrzej; Bentley, Robert D.;
Doschek, George A.; Watanabe, Tetsuya; Hiei, Eijiro; Lang, James;
Carter, Martin K.; Mariska, John T.; Phillips, Andrew T.; Phillips,
Kenneth J. H.; Pike, C. David; Sterling, Alphonse C.
1992PASJ...44L.101C Altcode:
We have analysed data from two flares of GOES class C7.1 and C8.5
observed by the Yohkoh Bragg Crystal Spectrometer. The high sensitivity
of the Yohkoh instrument allows us to observe the very early stages of
flare development and to study small events with a high signal-to-noise
ratio. Spectral fitting programs have been used to derive plasma
temperatures, emission measures and velocities from spectra of S XV,
Ca XIX and Fe XXV. Large plasma motions indicative of chromospheric
evaporation have been found. A more detailed analysis of a flare which
occurred on 1991 October 30 is presented.
---------------------------------------------------------
Title: The Status of YOHKOH in Orbit: an Introduction to the Initial
Scientific Results
Authors: Ogawara, Yoshiaki; Acton, Loren W.; Bentley, Robert D.;
Bruner, Marilyn E.; Culhane, J. Leonard; Hiei, Eijiro; Hirayama,
Tadashi; Hudson, Hugh S.; Kosugi, Takeo; Lemen, James R.; Strong, Keith
T.; Tsuneta, Saku; Uchida, Yutaka; Watanabe, Tetsuya; Yoshimori, Masato
1992PASJ...44L..41O Altcode:
In this introductory article accompanying the initial scientific
papers from the Yohkoh mission, we briefly summarize the design
and in-orbit function of the spacecraft and its four scientific
instruments. Although these initial results include mainly studies
based upon individual Yohkoh experiments at this early stage, there
are also analyses of combined data sets provided by several on-board
and ground-based instruments in progress. The results presented here,
and anticipated future results, suggest that the Yohkoh observations
with their comprehensive coverage of solar high-energy phenomena will
come to represent a significant milestone in the progress of solar
physics. This will be true not only regarding flares, but also for
fainter coronal structures and even coronal holes.
---------------------------------------------------------
Title: The YOHKOH mission for high-energy solar physics
Authors: Acton, L.; Tsuneta, S.; Ogawara, Y.; Bentley, R.; Bruner, M.;
Canfield, R.; Culhane, L.; Doschek, G.; Hiei, E.; Hirayama, T. Hudson,
H.; Kosugi, T.; Lang, J.; Lemen, J.; Nishimura, J.; Makishima, K.;
Uchida, Y.; Watanabe, T.
1992Sci...258..618A Altcode: 1992Sci...258..591A
Data on solar flare mechanisms and the sun's corona will be generated
by Japan's Yohkoh satellite's X-ray imaging sensors and X-ray and
gamma-ray spectrometers. It is noted that the X-ray corona above active
regions expands, in some cases almost continually, in contradiction of
the widely accepted model of magnetohydrostatic equilibrium in such
regions. Flaring X-ray bright points have been discovered to often
involve ejecta into an adjacent, much larger and fainter magnetic loop,
which brightens along its length at speeds up to 1000 km/sec.
---------------------------------------------------------
Title: YOHKOH Bragg Crystal Spectrometer Observations of the Dynamics
and Temperature Behavior of a Soft X-Ray Flare
Authors: Doschek, George A.; Mariska, John T.; Watanabe, Tetsuya;
Hiei, Eijiro; Lang, James; Culhane, J. Leonard; Bentley, Robert D.;
Brown, Charles M.; Feldman, Uri; Phillips, Andrew T.; Phillips,
Kenneth J. H.; Sterling, Alphonse C.
1992PASJ...44L..95D Altcode:
We describe X-ray spectra of an M1.5 flare that occurred on 1991
November 9, starting at about 0313 UT. This flare is unusual in that
very intense blueshifted components are observed in the resonance
lines of Fe XXV, Ca XIX, and S XV. During the onset of the flare,
the resonance lines of Ca XIX and Fe XXV are primarily due to
this blueshifted component, which from the Doppler effect indicates
line-of-sight speeds and turbulent motions that in combination extend
up to 800 km s(-1) .
---------------------------------------------------------
Title: The Performance of the YOHKOH Bragg Crystal Spectrometer
Authors: Lang, James; Bentley, Robert D.; Brown, Charles M.; Culhane,
J. Leonard; Doschek, George A.; Watanabe, Tetsuya; Hiei, Eijiro;
Deslattes, Richard D.; Fludra, Andrzej; Guttridge, Philip R.; Magraw,
John E.; Payne, Jeffrey; Pike, C. David; Trow, Matthew W.
1992PASJ...44L..55L Altcode:
An overview of the Yohkoh Bragg Crystal Spectrometer is given,
complemented by details of the laboratory testing prior to launch. The
in-orbit performance of the instrument is described.
---------------------------------------------------------
Title: The EUV mini-survey with the ROSAT wide field camera.
Authors: Pounds, K. A.; Abbey, A. F.; Barstow, M. A.; Bentley, R. D.;
Bewick, A.; Breeveld, E. R.; Cole, R. E.; Courtier, G. M.; Deeley, M.;
Denby, M.; Goodall, C. V.; Gourlay, J. A.; Guttridge, P. R.; Harris,
A. W.; Huckle, H. E.; Kent, B. J.; Lieu, R.; McCalden, A. J.; Page,
C. G.; Pankiewicz, G. S.; Ponman, T. J.; Pye, J. P.; Reading, D. H.;
Richards, A. G.; Ricketts, M. J.; Rochester, G. K.; Sansom, A. E.;
Sembay, S. E.; Sidher, S.; Sims, M. R.; Spragg, J. E.; Sumner, T. J.;
Swinyard, B. M.; Vallance, R. J.; Watson, D. J.; Watson, M. G.; Wells,
A. A.; Willingale, R.; Wright, J. S.
1991MNRAS.253..364P Altcode:
Following a successful launch on 1990 June 1, the ROSAT spacecraft and
its payload, consisting of an X-ray and an EUV telescope, underwent
two months of in-orbit calibration and detailed performance checks. A
preliminary observation of a small section of the sky, carried out
over July 11-16 (the `mini-survey') showed all ROSAT systems to
be functioning well and has allowed predictions to be made on the
ultimate productivity of both ROSAT all-sky surveys. An analysis of
the mini-survey data from the UK Wide Field Camera, has revealed 35
EUV sources, including several white dwarf stars, a variety of active
cool stars and several other objects. In all, 23 sources have probable
optical counterparts. Consideration of the effective exposure and sky
coverage in the mini- survey allows the prediction that the recently
completed ROSAT all-sky survey will yield in excess of a thousand new
EUV sources.
---------------------------------------------------------
Title: The Bragg Crystal Spectrometer for SOLAR-A
Authors: Culhane, J. L.; Hiei, E.; Doschek, G. A.; Cruise, A. M.;
Ogawara, Y.; Uchida, Y.; Bentley, R. D.; Brown, C. M.; Lang, J.;
Watanabe, T.; Bowles, J. A.; Deslattes, R. D.; Feldman, U.; Fludra,
A.; Guttridge, P.; Henins, A.; Lapington, J.; Magraw, J.; Mariska,
J. T.; Payne, J.; Phillips, K. J. H.; Sheather, P.; Slater, K.;
Tanaka, K.; Towndrow, E.; Trow, M. W.; Yamaguchi, A.
1991SoPh..136...89C Altcode:
The Bragg Crystal Spectrometer (BCS) is one of the instruments which
makes up the scientific payload of the SOLAR-A mission. The spectrometer
employs four bent germanium crystals, views the whole Sun and observes
the resonance line complexes of H-like FeXXVI and He-like FeXXV,
CaXIX, and SXV in four narrow wavelength ranges with a resolving power
(λ/Δλ) of between 3000 and 6000. The spectrometer has approaching
ten times better sensitivity than that of previous instruments thus
permitting a time resolution of better than 1 s to be achieved. The
principal aim is the measurement of the properties of the 10 to 50
million K plasma created in solar flares with special emphasis on the
heating and dynamics of the plasma during the impulsive phase. This
paper summarizes the scientific objectives of the BCS and describes
the design, characteristics, and performance of the spectrometers.
---------------------------------------------------------
Title: SOLAR-A Reformatted Data Files and Observing Log
Authors: Morrison, M. D.; Lemen, J. R.; Acton, L. W.; Bentley, R. D.;
Kosugi, T.; Tsuneta, S.; Ogawara, Y.; Watanabe, T.
1991SoPh..136..105M Altcode:
All of the SOLAR-A telemetry data will be reformatted before
distribution to the analysis computers and the various users. This
paper gives an overview of the files which will be created and the
format and organization which the files will use. The organization
has been chosen to be efficient in space, to ease access to the data,
and to allow for the data to be transportable to different machines. An
observing log file will be created automatically using the reformatted
data files as the input. It will be possible to perform searches with
the observing log to list cases where instruments are in certain modes
and/or seeing certain signal levels.
---------------------------------------------------------
Title: Iron and calcium abundances in solar flares from the
multi-temperature analysis of X-ray spectra
Authors: Fludra, A.; Bentley, R. D.; Culhane, J. L.; Lemen, J. R.;
Sylwester, J.
1991AdSpR..11a.155F Altcode: 1991AdSpR..11Q.155F
A generalized method of calculating the distribution of the emission
measure with temperature (DEM) for optically thin plasma has been
developed. The method simultaneously uses line flux ratios in addition
to line fluxes. When a ratio of lines from the same element is used,
the resulting DEM is independent of this element's abundance. The method
has been applied to derive the absolute abundances of iron in solar
flares from X-ray spectra recorded by the Bent Crystal Spectrometer on
SMM. The iron abundances have been found to vary between flares. The
calcium abundances have also been calculated using the same method and
are found to be in close agreement with the values derived from the
line-to-continuum technique (Lemen et al., 1990 and Sylwester et al.,
1990). The variation of iron and calcium abundances is compared. A
correction to the ionization balance for iron is proposed.
---------------------------------------------------------
Title: The SOLAR-A Bragg Crystal Spectrometer (Extended Abstract)
Authors: Culhane, J. L.; Hiei, E.; Bentley, R. D.; Brown, C. M.;
Doschek, G. A.; Feldman, U.; Lang, J.; Watanabe, T.
1991LNP...387...22C Altcode: 1991fpsa.conf...22C
No abstract at ADS
---------------------------------------------------------
Title: Early results from the ROSAT Wide Field Camera
Authors: Barstow, M. A.; Abbey, A. F.; Cole, R. E.; Denby, M.; Page,
C. G.; Pankiewicz, G. S.; Pounds, K. A.; Pye, J. P.; Sansom, A. E.;
Sims, M. R.; Spragg, J. E.; Watson, D. J.; Wells, A. A.; Willingale,
R.; Courtier, G. M.; Gourlay, J. A.; Harris, A. W.; Kent, B. J.;
Reading, D. H.; Richards, A. G.; Swinyard, B. M.; Wright, J. S.;
Goodall, C. V.; Bentley, R. D.; Breeveld, E. R.; Guttridge, P. R.;
Huckle, H. E.; McCalden, A. J.; Bewick, A.; Rochester, G. K.; Sumner,
T. J.
1991ASIC..336...99B Altcode: 1991whdw.conf...99B
No abstract at ADS
---------------------------------------------------------
Title: Plasma diagnostics with the Solar-A Bragg Crystal Spectrometer
Authors: Culhane, J. L.; Hiei, E.; Bentley, R. D.; Brown, C. M.;
Doschek, G. A.; Feldman, U.; Lang, J.; Watanabe, T.
1991AdSpR..11e..77C Altcode: 1991AdSpR..11...77C
A Bragg Crystal spectrometer is one of the instruments on the Solar-A
mission. Using bent crystals, the spectrometer will observe the
resonance line complexes of the H-like Fe XXVI, and He-like Fe XXV
and Ca XIX ions with a sensitivity 5 to 10 times that of the SMM Bent
Crystal Spectrometer. It will also study the lower temperature lines
of He-like S XV. The improved sensitivity will allow observations
much earlier in the impulsive phase of flares than has previously been
possible. The new observations should help to answer questions about
plasma heating and dynamics. As well as providing information on line
profiles and shifts, the selected spectral lines will also provide
electron temperature and emission measure estimates over a range from
5 to 50 MK. The onboard microprocessor will permit spectral resolution
to be traded against time resolution during an observation.
---------------------------------------------------------
Title: On the Dependence of Solar Flare X-Ray Spectral Line Intensity
Ratios of Highly Ionized Sulfur, Calcium, and Iron on Electron
Temperature, Differential Emission Measure, and Atomic Physics
Authors: Doschek, G. A.; Fludra, A.; Bentley, R. D.; Lang, J.;
Phillips, K. J. H.; Watanabe, T.
1990ApJ...358..665D Altcode:
This paper focuses on what can be learned about the emission measure
distribution and certain atomic physics parameters from spectral lines
of highly ionized ions of sulfur, calcium, and iron that appear in
solar flare spectra. The particular lines chosen for analysis allow the
electron temperature to be determined independently of the assumption
of ionization equilibrium. An attempt is made to find emission measure
models based on selected functional dependences of emission measure
on temperature that reproduce the observed temperatures deduced from
spectral line ratios as well as the relative intensities of resonance
lines of different elements.
---------------------------------------------------------
Title: Investigation of non-uniform heating during the decay phase
of solar flares
Authors: Sylwester, B.; Sylwester, J.; Bentley, R. D.; Fludra, A.
1990SoPh..126..177S Altcode:
We have analysed X-ray spectra of 13 solar flares as obtained
by the Bent Crystal Spectrometer (BCS) on the Solar Maximum
Mission. In particular, we have examined the observed ratio of
T<SUB>Fe</SUB>/T<SUB>Ca</SUB> where T<SUB>Fe</SUB> and T<SUB>Ca</SUB>
are the temperatures obtained from the FeXXV and CaXIX spectra,
respectively. In order to simplify the investigation we have analysed
only flares which reach quasi-steady-state during the decay. It
turned out that the observed ratios cannot be explained by a model
consisting of a single, uniformly heated loop, with a constant or
variable cross-sectional area. We propose that this problem may be
solved by introducing some distribution of the heating function across
the flaring loop. This model has been tested by detailed calculations.
---------------------------------------------------------
Title: The Decay Phase of Three Large Solar Flares
Authors: Fludra, A.; Bentley, R. D.; Culhane, J. L.; Jakimiec, J.;
Lemen, J. R.; Sylwester, J.; Moorthy, S. T.
1990PDHO....7..266F Altcode: 1990ESPM....6..266F; 1990dysu.conf..266F
No abstract at ADS
---------------------------------------------------------
Title: Study of Non-Uniform Heating in Solar Flares
Authors: Sylwester, B.; Sylwester, J.; Jakimiec, J.; Serio, S.; Reale,
F.; Bentley, R. D.; Fludra, A.
1990PDHO....7..255S Altcode: 1990ESPM....6..255S; 1990dysu.conf..255S
The authors have analyzed the ratios of the temperatures derived from Fe
and Ca spectra (T<SUB>Fe</SUB>/T<SUB>Ca</SUB>) for the rising phase of
11 solar flares. Corresponding hydrodynamic models have been calculated
and the obtained results are compared with the observational data for
selected flares.
---------------------------------------------------------
Title: Position-sensitive proportional counter for the Bragg Crystal
Spectrometer on Solar-A
Authors: Lapington, J. S.; Trow, M. W.; Bentley, R. D.; Cilhane, J. L.
1989SPIE.1159..252L Altcode:
The gas proportional counter used for X-ray detection on the Solar-A
Bragg Crystal Spectrometer Instrument is described. The sealed detector
utilizes a multianode geometry together with a wedge and wedge (or
backgammon) cathode pattern to provide one-dimensional imaging along
the dispersion axis. The development program has now arrived at a
design for the prototype detector. Results of the imaging performance,
energy resolution, and count-rate capability are psesented.
---------------------------------------------------------
Title: Turbulent and Directed Plasma Motions in Solar Flares
Authors: Fludra, A.; Lemen, J. R.; Jakimiec, J.; Bentley, R. D.;
Sylwester, J.
1989ApJ...344..991F Altcode:
An improved method for fitting asymmetric soft X-ray line profiles
from solar flares is presented. A two-component model is used where one
component represents the total emission from directed upflow plasma and
the other the emission from the plasma at rest. Unlike previous methods,
the width of the moving component is independent from that of the
stationary component. Time variations of flare plasma characteristics
(i.e., temperature, emission measure of moving and stationary plasma,
upflow and turbulent velocities) are derived from the Ca XIX and Fe XXV
spectra recorded by the Bent Crystal Spectrometer on the Solar Maximum
Mission. The fitting technique provides a statistical estimation
for the uncertainties in the fitting parameters. The relationship
between the directed and turbulent motions has been studied, and
a correlation of the random and directed motions has been found in
some flares with intensive plasma upflows. Mean temperatures of the
upflowing and stationary plasmas are compared for the first time from
ratios of calcium to iron X-ray line intensities. Finally, evidence
for turbulent motions and the possibility of plasma upflow late into
the decay phase is presented and discussed.
---------------------------------------------------------
Title: Comparison of the Microwave and Soft X-Ray Emission above
a Sunspot
Authors: Siarkowski, M.; Sylwester, J.; Jakimiec, J.; Bentley, R. D.
1989SoPh..119...65S Altcode:
The Westerbork Synthesis Radio Telescope (WSRT) 6 cm radio observations
of the active region HL 16864 large spot (Strong, Alissandrakis,
and Kundu, 1984) are compared with X-ray data obtained from the Flat
Crystal Spectrometer (FCS) onboard the Solar Maximum Mission satellite
on May 25, 1980. The X-ray data confirm the presence of a temperature
depression above the spot umbra in agreement with suggestions obtained
from radio data analysis. Significant differences in the spatial
distribution of both kinds of emission observed in the corona above
this spot are attributed mainly to the strong resonant character of the
cyclotron radio radiation. Some differences are also caused by both
the relatively low efficiency and the low spatial resolution of the
FCS. Deconvolution of X-ray images allows to see the new structures
and enhances the mutual correlation between X-ray and radio pictures.
---------------------------------------------------------
Title: Flare energetics.
Authors: Wu, S. T.; de Jager, C.; Dennis, B. R.; Hudson, H. S.;
Simnett, G. M.; Strong, K. T.; Bentley, R. D.; Bornmann, P. L.; Bruner,
M. E.; Cargill, P. J.; Crannell, C. J.; Doyle, J. G.; Hyder, C. L.;
Kopp, R. A.; Lemen, J. R.; Martin, S. F.; Pallavicini, R.; Peres,
G.; Serio, S.; Sylwester, J.; Veck, N. J.
1989epos.conf..377W Altcode:
The authors have sought to establish a comprehensive and self-consistent
picture of the sources and transport of energy within a flare. To
achieve this goal, they chose five flares in 1980 that were well
observed with instruments on the Solar Maximum Mission, and with other
space-borne and ground-based instruments. The events were chosen to
represent various types of flares. Details of the observations available
for them and the corresponding physical parameters derived from these
data are presented. The flares were studied from two perspectives,
the impulsive and gradual phases, and then the results were compared
to obtain the overall picture of the energetics of these flares. The
authors also discuss the role that modeling can play in estimating the
total energy of a flare when the observationally determined parameters
are used as the input to a numerical model. Finally, a critique of
our current understanding of flare energetics and the methods used to
determine various energetics terms is outlined, and possible future
directions of research in this area are suggested.
---------------------------------------------------------
Title: Preflare activity.
Authors: Priest, E. R.; Gaizauskas, V.; Hagyard, M. J.; Schmahl, E. J.;
Webb, D. F.; Cargill, P.; Forbes, T. G.; Hood, A. W.; Steinolfson,
R. S.; Chapman, G. A.; Deloach, A. C.; Gary, G. A.; Jones, H. P.;
Karpen, J. T.; Martres, M. -J.; Porter, J. G.; Schmieder, B.; Smith,
J. B., Jr.; Toomre, J.; Woodgate, B.; Waggett, P.; Bentley, R.;
Hurford, G.; Schadee, A.; Schrijver, J.; Harrison, R.; Martens, P.
1989epos.conf....1P Altcode:
Contents: 1. Introduction. 2. Magnetohydrodynamic
instability. 3. Preflare magnetic and velocity fields. 4. Coronal
manifestations of preflare activity.
---------------------------------------------------------
Title: Largescale Magnetic Field Phenomena
Authors: Harrison, R. A.; Bentley, R. D.; Brosius, J.; Dwivedi,
B. N.; Jardine, M.; Klimchuk, J. A.; Kundu, M. R.; Pearce, G.; Saba,
J.; Sakurai, T.; Schmahl, E. J.; Schmelz, J.; Sime, D. G.; Steele,
C. D. C.; Sun, M. T.; Tappin, S. J.; Waljeski, K.; Wang, A. H.; Wu,
S. T.
1989tnti.conf....1H Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Time variations of the calcium elemental abundance in flares
from NOAA active regions 2562 and 2779.
Authors: Sylwester, J.; Zolcinski-Couet, M. -C.; Bentley, R. D.;
Lemen, J. R.
1988JPhys..49..189S Altcode: 1988IAUCo.102..189S
Analysis of flare spectra obtained with the Bent Crystal Spectrometer
aboard the Solar Maximum Mission (SMM) satellite enables the
determination of the fluxes in the resonance (w) line of Ca XIX and
the near-by continuum. The line-to-continuum intensity ratio is a
sensitive measure of the calcium elemental abundance (A<SUB>Ca</SUB>)
relative to hydrogen in the emitting plasma. The authors analyse
the variations of A<SUB>Ca</SUB> for flares which occurred in two
active regions well observed by SMM. They conclude that it is not
possible to correlate the abundance variations with the time of the
flare occurrence as suggested in an earlier paper for flares produced
from a single active region. Further, the authors find no convincing
correlation of abundance variation with any other flare characteristics.
---------------------------------------------------------
Title: Intercomparison of flare observations with two SMM
spectrometers: BCS and HXIS
Authors: Jakimiec, J.; Prés, P.; Fludra, A.; Bentley, R. D.; Lemen,
J. R.; Mewe, R.; Schrijver, J.; Sylwester, J.
1988AdSpR...8k.231J Altcode: 1988AdSpR...8..231J
The temperature diagnostics of hot flare plasma, obtained from two
Solar Maximum Mission instruments (HXIS and BCS), is compared. A good
general agreement between the HXIS and BCS-Fe temperature scales has
been found. However, for the growth phase of some flares a systematic
difference, T<SUB>HXIS</SUB>>T<SUB>Fe</SUB>, has been found,
which is not likely to be due to the typical non-thermal electron
beams. Possible explanation of this effect is briefly discussed.
---------------------------------------------------------
Title: Investigations of Turbulent and Direct Motions in Solar Flares
Authors: Bentley, R. D.; Fludra, A.; Lemen, J. R.; Jakimiec, J.;
Sylwester, J.
1987BAAS...19R.750B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Variation in Calcium Abundance during Flares
Authors: Sylwester, J.; Lemen, J. R.; Mewe, R.; Bentley, R. D.;
Sylwester, B.
1987sman.work..123S Altcode:
The authors discuss the variation of the line-to-continuum ratio
throughout the entire flare including the temperature rise phase.
---------------------------------------------------------
Title: High-Temperature Plasma Diagnostics of Solar Flares and
Comparison with Model Calculations
Authors: Jakimiec, J.; Sylwester, B.; Sylwester, J.; Lemen, J. R.;
Mewe, R.; Bentley, R. D.; Peres, G.; Serio, S.; Schrijver, J.
1987sman.work...91J Altcode:
The present state of flare diagnostics from X-ray spectra is briefly
outlined. The authors discuss how improved diagnostic results can be
used in flare heating process investigations.
---------------------------------------------------------
Title: Flare energetics
Authors: Wu, S. T.; De Jager, C.; Dennis, B. R.; Hudson, H. S.;
Simnett, G. M.; Strong, K. T.; Bentley, R. D.; Bornmann, P. L.;
Bruner, M. E.; Cargill, P. J.
1986epos.conf..5.1W Altcode: 1986epos.confE...1W
In this investigation of flare energetics, researchers sought
to establish a comprehensive and self-consistent picture of the
sources and transport of energy within a flare. To achieve this
goal, they chose five flares in 1980 that were well observed with
instruments on the Solar Maximum Mission, and with other space-borne
and ground-based instruments. The events were chosen to represent
various types of flares. Details of the observations available for
them and the corresponding physical parameters derived from these
data are presented. The flares were studied from two perspectives,
the impulsive and gradual phases, and then the results were compared
to obtain the overall picture of the energics of these flares. The
role that modeling can play in estimating the total energy of a flare
when the observationally determined parameters are used as the input
to a numerical model is discussed. Finally, a critique of the current
understanding of flare energetics and the methods used to determine
various energetics terms is outlined, and possible future directions
of research in this area are suggested.
---------------------------------------------------------
Title: Characterization of the Total Flare Energy
Authors: Wu, S. T.; de Jager, C.; Dennis, B. R.; Hudson, H. S.;
Simnett, G. M.; Strong, K. T.; Bentley, R. D.; Bornmann, P. L.; Bruner,
M. E.; Cargill, P. J.; Crannell, C. J.; Doyle, J. G.; Hyder, C. L.;
Kopp, R. A.; Lemen, J. R.; Martin, S. F.; Pallavicini, R.; Peres,
G.; Serio, S.; Sylwester, J.; Veek, N. J.
1986epos.conf.5.41W Altcode: 1986epos.confE..41W
No abstract at ADS
---------------------------------------------------------
Title: Energetics of the Impulsive Phase
Authors: Wu, S. T.; de Jager, C.; Dennis, B. R.; Hudson, H. S.;
Simnett, G. M.; Strong, K. T.; Bentley, R. D.; Bornmann, P. L.; Bruner,
M. E.; Cargill, P. J.; Crannell, C. J.; Doyle, J. G.; Hyder, C. L.;
Kopp, R. A.; Lemen, J. R.; Martin, S. F.; Pallavicini, R.; Peres,
G.; Serio, S.; Sylwester, J.; Veek, N. J.
1986epos.conf..5.5W Altcode: 1986epos.confE...5W
No abstract at ADS
---------------------------------------------------------
Title: Coronal manifestations of preflare activity
Authors: Schmahl, E. J.; Webb, D. F.; Woodgate, B.; Waggett, P.;
Bentley, R.; Hurford, G.; Schadee, A.; Schrijver, J.; Harrison, R.;
Martens, P.
1986epos.conf.1.48S Altcode: 1986epos.confA..48S
A variety of coronal manifestations of precursors or preheating for
flares are discussed. Researchers found that almost everyone with a
telescope sees something before flares. Whether an all-encompassing
scenario will ever be developed is not at all clear at present. The
clearest example of preflare activity appears to be activated filaments
and their manifestations, which presumably are signatures of a changing
magnetic field. But researchers have seen two similar eruptions, one
without any evidence of emerging flux (Kundu et al., 1985) and the
other with colliding poles (Simon et al., 1984). While the reconnection
of flux is generally agreed to be required to energize a flare, the
emergence of flux from below (at least on short timescales and in
compact regions) does not appear to be a necessary condition. In some
cases the cancelling of magnetic flux (Martin, 1984) by horizontal
motions instead may provide the trigger (Priest, 1985) Researchers
found similarities and some differences between these and previous
observations. The similarities, besides the frequent involvement of
filaments, include compact, multiple precursors which can occur both at
and near (not at) the flare site, and the association between coronal
sources and activity lower in the atmosphere (i.e., transition zone
and chromosphere).
---------------------------------------------------------
Title: Energetics of the Gradual Phase
Authors: Wu, S. T.; de Jager, C.; Dennis, B. R.; Hudson, H. S.;
Simnett, G. M.; Strong, K. T.; Bentley, R. D.; Bornmann, P. L.; Bruner,
M. E.; Cargill, P. J.; Crannell, C. J.; Doyle, J. G.; Hyder, C. L.;
Kopp, R. A.; Lemen, J. R.; Martin, S. F.; Pallavicini, R.; Peres,
G.; Serio, S.; Sylwester, J.; Veek, N. J.
1986epos.conf.5.20W Altcode: 1986epos.confE..20W
No abstract at ADS
---------------------------------------------------------
Title: Review of Impulsive Phase Phenomena
Authors: Wu, S. T.; de Jager, C.; Dennis, B. R.; Hudson, H. S.;
Simnett, G. M.; Strong, K. T.; Bentley, R. D.; Bornmann, P. L.; Bruner,
M. E.; Cargill, P. J.; Crannell, C. J.; Doyle, J. G.; Hyder, C. L.;
Kopp, R. A.; Lemen, J. R.; Martin, S. F.; Pallavicini, R.; Peres,
G.; Serio, S.; Sylwester, J.; Veek, N. J.
1986epos.conf.5.60W Altcode: 1986epos.confE..60W
No abstract at ADS
---------------------------------------------------------
Title: Flares Chosen for Energetics Study
Authors: Wu, S. T.; de Jager, C.; Dennis, B. R.; Hudson, H. S.;
Simnett, G. M.; Strong, K. T.; Bentley, R. D.; Bornmann, P. L.; Bruner,
M. E.; Cargill, P. J.; Crannell, C. J.; Doyle, J. G.; Hyder, C. L.;
Kopp, R. A.; Lemen, J. R.; Martin, S. F.; Pallavicini, R.; Peres,
G.; Serio, S.; Sylwester, J.; Veek, N. J.
1986epos.conf.5.47W Altcode: 1986epos.confE..47W
No abstract at ADS
---------------------------------------------------------
Title: Relationships among the Phases
Authors: Wu, S. T.; de Jager, C.; Dennis, B. R.; Hudson, H. S.;
Simnett, G. M.; Strong, K. T.; Bentley, R. D.; Bornmann, P. L.; Bruner,
M. E.; Cargill, P. J.; Crannell, C. J.; Doyle, J. G.; Hyder, C. L.;
Kopp, R. A.; Lemen, J. R.; Martin, S. F.; Pallavicini, R.; Peres,
G.; Serio, S.; Sylwester, J.; Veek, N. J.
1986epos.conf.5.39W Altcode: 1986epos.confE..39W
No abstract at ADS
---------------------------------------------------------
Title: Broadening of soft X-ray lines during the impulsive phase of
solar flares - Random or directed mass motions?
Authors: Doyle, J. G.; Bentley, R. D.
1986A&A...155..278D Altcode:
The authors present spectroscopic data for three flares obtained with
the Bent Crystal Spectrometer flown in the Solar Maximum Mission in
1980. This data is concerned with the structure of the Ca XIX resonance
line at 3.176 Å during the impulsive phase of flares. On the basis of
high time resolution (6s.) data, the authors suggest that the previous
published results concerned with the excess broadening of the resonance
line being due to bulk random mass motions may give an over-simplified
picture. Instead the authors suggest that during this stage of the
flare, the resonance line consists of many discrete features, which
are interpreted as mass flows.
---------------------------------------------------------
Title: Preflare activity.
Authors: Priest, E. R.; Gaizauskas, V.; Hagyard, M. J.; Schmahl, E. J.;
Webb, D. F.; Cargill, P.; Forbes, T. G.; Hood, A. W.; Steinolfson,
R. S.; Chapman, G. A.; Deloach, A. C.; Gary, G. A.; Jones, H. P.;
Karpen, J. T.; Martres, M. -J.; Porter, J. G.; Schmieder, B.; Smith,
J. B., Jr.; Toomre, J.; Woodgate, B.; Waggett, P.; Bentley, R.;
Hurford, G.; Schadee, A.; Schrijver, J.; Harrison, R.; Martens, P.
1986NASCP2439....1P Altcode:
Contents: 1. Introduction: the preflare state - a review of previous
results. 2. Magnetohydrodynamic instability: magnetic reconnection,
nonlinear tearing, nonlinear reconnection experiments, emerging flux and
moving satellite sunspots, main phase reconnection in two-ribbon flares,
magnetic instability responsible for filament eruption in two-ribbon
flares. 3. Preflare magnetic and velocity fields: general morphology of
the preflare magnetic field, magnetic field shear, electric currents in
the preflare active region, characterization of the preflare velocity
field, emerging flux. 4. Coronal manifestations of preflare activity:
defining the preflare regime, specific illustrative events, comparison
of preflare X-rays and ultraviolet, preflare microwave intensity and
polarization changes, non-thermal precursors, precursors of coronal
mass ejections, short-lived and long-lived HXIS sources as possible
precursors.
---------------------------------------------------------
Title: Observational evidences for coronal temperature depression
above sunspot umbra
Authors: Siarkowski, M.; Bentley, R. D.; Jakimiec, J.; Sylwester, J.
1986CoSka..15..677S Altcode:
Three large spots observed by the X-ray Polychromator on the Solar
Maximum Mission satellite are analysed. The X-ray spectroheliograms were
used to derive the two-dimensonal electron temperature distribution. For
one of these spots, observed simultaneously by the Westerbork Synthesis
Radiotelescope at 6 cm, the temperature minimum corresponds to the
centre of a microwave ring structure. This confirms the existence of
a temperature depression above the spot umbra.
---------------------------------------------------------
Title: Differential emission measure distributions of Capella and
σ<SUP>2</SUP> CrB
Authors: Mewe, R.; Schrijver, C. J.; Lemen, J. R.; Bentley, R. D.
1986AdSpR...6h.133M Altcode: 1986AdSpR...6..133M
The active late-type stars Capella (α Aur G6III+F9III) and
σ<SUP>2</SUP> CrB (F6V+GV) (X-ray candidate emitters underlined)
were observed with the EXOSAT Transmission Grating Spectrometer
(TGS) in the region 10-200 Å. We have made an analysis of the
differential emission measure (DEM) distribution. The derived DEM
peaks between 3 and 7 MK and above 10 MK. The results disagree with
models for static loops as developed by Rosner, Tucker and Vaiana [1,
hereafter referred to as RTV]: the contrast in emission between the
maximal and lower temperatures in the loop is larger than predicted by
the RTV model. Other models which predict DEM distributions falling
off more steeply towards lower temperatures are briefly discussed:
e.g. quasi-static loops with varying cross-sectional area or dynamic
loops with strong downward flows.
---------------------------------------------------------
Title: Physical conditions in a large flare loop on Nov. 1980 derived
from SMM observations
Authors: Sylwester, B.; Sylwester, J.; Jakimiec, J.; Fludra, A.;
Bentley, R. D.; Schrijver, J.
1986CoSka..15..145S Altcode:
The authors present the study of a large X-ray loop related to the
H-alpha 2N flare close to the center of the solar disc. Data from Solar
Maximum Mission have been used in the analysis. The authors have derived
the temperatures, densities and the geometrical parameters (length,
diameter) for a hot core and for a cooler envelope of the flaring loop.
---------------------------------------------------------
Title: Soft X-ray observations of high-velocity features in the 29
June 1980 flares
Authors: Bentley, R. D.; Lemen, J. R.; Culhane, J. L.; Phillips,
K. J. H.
1986A&A...154..255B Altcode:
During the impulsive phase of two flares on 29 June 1980, short
lived emission line features have been observed in soft X-rays,
near the resonance lines of Fe XXV and Ca XIX, by the Bent Crystal
Spectrometer on the Solar Maximum Mission. They are coincident with hard
X-ray bursts and with the onset of Hα sprays. They appear to result
from a different type of phenomenon from the unresolved blue-shifted
component from the resonance lines reported by Feldman et al. (1980)
and Antonucci et al. (1982). The authors believe that these discrete
line features are due to Doppler-shifted resonance line emission from
well collimated, moving plasma with large line-of-sight velocities.
---------------------------------------------------------
Title: Orbital debris environment resulting from future activities
in space
Authors: Simnett, G. M.; Phillips, K. J. H.; Bentley, R. D.
1986AdSpR...6f.109S Altcode: 1986AdSpR...6..109S
A long-term evolution of space debris environment has been simulated by
a numerical model. Based on previously published results in many 50-year
runs of the “dynamic model”, an “average model” is derived to reduce
the computation time in order to effectively simulate a very-long-term
evolution of space debris environment. The evolution of space debris
environment is examined with two different future space activities
in LEO: (1) Increase the yearly traffic input of new satellites by
2%, 5%, 10%, 20%, and 50%; and (2) place ten large space structures
of 100 meters in diameter in the year 1995 at either 500 km or 1000
km altitude. The results indicate that in a 170-year span from 1983,
every space activity listed above results in a rapid runaway of debris
fluxes from objects of 4 mm or larger.
---------------------------------------------------------
Title: Flare energetics.
Authors: Wu, S. T.; de Jager, C.; Dennis, B. R.; Hudson, H. S.;
Simnett, G. M.; Strong, K. T.; Bentley, R. D.; Bornmann, P. L.; Bruner,
M. E.; Cargill, P. J.; Crannell, C. J.; Doyle, J. G.; Hyder, C. L.;
Kopp, R. A.; Lemen, J. R.; Martin, S. F.; Pallavicini, R.; Peres,
G.; Serio, S.; Sylwester, J.; Veck, N. J.
1986NASCP2439....5W Altcode:
In this investigation of flare energetics, the authors establish a
comprehensive and self-consistent picture of the sources and transport
of energy within a flare. They chose five flares in 1980 that were
well observed with instruments on the SMM, and with other space-borne
and ground-based instruments. Details of the observations available
for them and the corresponding physical parameters derived from these
data are presented. The flares were studied from two perspectives,
the impulsive and gradual phases, and then the results were compared
to obtain the overall picture of the energetics of these flares. The
authors also discuss the role that modeling can play in estimating the
total energy of a flare when the observationally determined parameters
are used as the input to a numerical model.
---------------------------------------------------------
Title: Determination of the calcium elemental abundance for 43 flares
from SMM-XRP solar X-ray spectra
Authors: Lemen, J. R.; Sylwester, J.; Bentley, R. D.
1986AdSpR...6f.245L Altcode: 1986AdSpR...6..245L
The helium and lithium-like X-ray transitions of Ca XVIII-XIX have been
used to make an absolute measurement of the coronal calcium elemental
abundance relative to hydrogen (A<SUB>Ca</SUB>) in solar flares. Cooling
phase spectra of 43 flares obtained in channel 1 of the Bent Crystal
Spectrometer (BCS) on the Solar Maximum Mission have been analyzed. The
abundance is determined from the intensity ratio of the Ca XIX resonance
line (<SUP>1</SUP>S<SUB>0</SUB> - <SUP>1</SUP>P<SUB>1</SUB>) and
nearby continuum. A large variation is observed in the values of the
derived abundances, ranging up to a factor of 2.5 between the extreme
cases. This confirms the earlier results of Sylwester, Lemen, and Mewe
[1], who investigated a smaller sample of flares. In addition to the
variability of A<SUB>Ca</SUB> observed between different flares, it
was suggested [1] that A<SUB>Ca</SUB> varies during the heating phase
of some flares. We neglect this phenomenon in the present work, and
concentrate on the cooling phase during which A<SUB>Ca</SUB> appears
to remain constant for any individual flare. Attempts to correlate
the A<SUB>Ca</SUB> measurements with other observable features are
discussed.
---------------------------------------------------------
Title: Soft X-ray emission from solar flares and active regions
Authors: Bentley, Robert Duncan
1986PhDT.......170B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The X-Ray Signature of Solar Coronal Mass Ejections
Authors: Harrison, R. A.; Waggett, P. W.; Bentley, R. D.; Phillips,
K. J. H.; Bruner, M.; Dryer, M.; Simnett, G. M.
1985SoPh...97..387H Altcode:
The coronal response to six solar X-ray flares has been investigated. At
a time coincident with the projected onset of the white-light coronal
mass ejection associated with each flare, there is a small, discrete
soft X-ray enhancement. These enhancements (precursors) precede by
typically ∼20 m the impulsive phase of the solar flare which is
dominant by the time the coronal mass ejection has reached an altitude
above 0.5 R<SUB>⊙</SUB>. We identify motions of hot X-ray emitting
plasma, during the precursors, which may well be a signature of the
mass ejection onsets. Further investigations have also revealed a
second class of X-ray coronal transient, during the main phase of the
flare. These appear to be associated with magnetic reconnection above
post-flare loop systems.
---------------------------------------------------------
Title: The X-ray signature of solar coronal mass ejections.
Authors: Harrison, R. A.; Waggett, P. W.; Bentley, R. D.; Phillips,
K. J. H.; Bruner, M.; Dryer, M.; Simnett, G. M.
1985RALR...84.....H Altcode:
The coronal response to six solar X-ray flares has been investigated. At
a time coincident with the projected onset of the white-light coronal
mass ejection with each flare, there is a small, discrete soft X-ray
enhancement. These enhancements (precursors) precede by typically
≡20 m the impulsive phase of the solar flare which is dominant by
the time the coronal mass ejection has reached an altitude above 0.5
R_sun;. The authors identify motions of hot X-ray emitting plasma,
during the precursors, which may well be a signature of the mass
ejection onsets. Further investigations have also revealed a second
class of X-ray coronal transients, during the main phase of the
flare. These appear to be associated with magnetic reconnection above
post-flare loop systems.
---------------------------------------------------------
Title: Soft X-ray observations of high-velocity features in the 29
June 1980flares.
Authors: Bentley, R. D.; Lemen, J. R.; Phillips, K. J. H.; Culhane,
J. L.
1985RALR...85.....B Altcode:
During the impulsive phase of two flares on 29 June 1980, short
lived emission line features have been observed in soft X-rays,
near the resonance lines of Fe XXV and Ca XIX, by the Bent Crystal
Spectrometer on the Solar Maximum Mission. They are coincident with hard
X-ray bursts and with the onset of Hα sprays. They appear to result
from a different type of phenomenon from the unresolved blue-shifted
component from the resonance lines reported by Feldman et al. (1980)
and Antonucci et al. (1982). The authors believe that these discrete
line features are due to Doppler-shifted resonance line emission from
well collimated, moving plasma with large line-of-sight velocities.
---------------------------------------------------------
Title: Recent Solar Observations from the X-Ray Polychromator on
the Repaired SMM Satellite
Authors: Saba, J. L. R.; Slater, G. L.; Levay, M. X.; Smith, K. L.;
Strong, K. T.; Bentley, R. D.; Lemen, J. R.; Caffey, R. R.; Freeland,
S. L., Jr.; Mathur, D. P.; Phillips, K. J. H.; Waters, T. A.
1984BAAS...16..726S Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Relationships of a growing magnetic flux region to flares
Authors: Martin, S. F.; Bentley, R. D.; Schadee, A.; Antalova, A.;
Kucera, A.; Dezső, L.; Gesztelyi, L.; Harvey, K. L.; Jones, H.;
Livi, S. H. B.; Wang, J.
1984AdSpR...4g..61M Altcode: 1984AdSpR...4...61M
Some sites for solar flares are known to develop where new magnetic
flux emerges and becomes abutted against opposite polarity pre-existing
magnetic flux (review by Galzauskas/1/). We have identified and analyzed
the evolution of such flare sites at the boundaries of a major new and
growing magnetic flux region within a complex of active regions, Hale
No. 16918. This analysis was done as a part of a continuing study of the
circumstances associated with flares in Hale Region 16918, which was
designated as an FBS target during the interval 18 - 23 June 1980. We
studied the initiation and development of both major and minor flares in
Hα images in relation to the identified potential flare sites at the
boundaries of the growing flux region and to the general development
of the new flux. This study lead to our recognition of a spectrum of
possible relationships of growing flux regions to flares as follows:
(1) intimate interaction with adjacent old flux - flare sites centered
at new/old flux boundary, (2) forced or “intimidated” interaction
in which new flux pushes old field having lower flux density towards a
neighboring old polarity inversion line where a flare then takes place,
(3) “influential” interaction - magnetic lines of force over an old
polarity inversion line, typically containing a filament, reconnect to
the new emerging flux; a flare occurs with erupting filament when the
magnetic field overlying the filament becomes too weak to prevent its
eruption, (4) inconsequential interaction - new flux region is too small
or has wrong orientation for creating flare conditions, (5) incidental -
flare occurs without any significant relationship to new flux regions.
---------------------------------------------------------
Title: Differential emission measure analysis of hot-flare plasma
from solar-maximum mission X-ray data
Authors: Jakimiec, J.; Sylwester, J.; Lemen, J. R.; Mewe, R.; Bentley,
R. D.; Fludra, A.; Schrijver, J.; Sylwester, B.
1984AdSpR...4g.203J Altcode: 1984AdSpR...4..203J
We have investigated differential emission measure (DEM) distribution
of hot flare plasma (T>10 MK) using SMM X-ray data from Bent Crystal
Spectrometer (BCS) and Hard X-ray Imaging Spectrometer (HXIS). We have
found that the analysis provide a very sensitive test of consistency
of observational data coming from different instruments or different
channels of the same instrument. This has allowed to eliminate some
systematic differences contained in the analysed data. <P />Typical
examples of the DEM distribution are discussed. It is stressed that
these improvements in the multitemperature flare diagnostics are very
important for the discussion of flare energetics.
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Title: SMM flat crystal spectrometer data analysis of 7 April
1980 flare.
Authors: Sylwester, B.; Sylwester, J.; Jakimiec, J.; Mewe, R.; Bentley,
R. D.
1983PDHO....5...85S Altcode: 1984PDHO....5...85S
The authors have analysed soft X-ray images of the 1B/M4 flare of 7
April 1980 recorded by Flat Crystal Spectrometer aboard Solar Maximum
Mission satellite. The X-ray flare consisted of two patches about 1
arcmin apart. A comparison with magnetograms and white light images
indicates that the two soft X-ray patches originate from two different
loops or systems of loops. For two selected resolution elements of
the X-ray pictures a detailed differential emission measure analysis
has been carried out and time evolution of the mean electron density
and thermal energy content has been investigated.
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Title: Active region magnetic fields inferred from simultaneous VLA
microwave maps, X-ray spectroheliograms, and magnetograms
Authors: Schmahl, E. J.; Kundu, M. R.; Strong, K. T.; Bentley, R. D.;
Smith, J. B., Jr.; Krall, K. R.
1982SoPh...80..233S Altcode:
A series of VLA maps at 6 cm wavelength have been generated from
observations of a solar active region (NOAA 2363) on 29 and 30 March,
1980. During the same period, X-ray spectroheliograms were acquired
for this region in the lines of O VIII, Ne IX, Mg XI, Si XIII, S
XV, and Fe XXV, with X-rayn Polychromator (XRP) aboard the Solar
Maximum Mission (SMM). Intervals of relative quiescence (i.e.,
when X-ray flares and centimeter wave bursts were not evident)
were selected for microwave mapping. The resulting VLA maps have
spatial resolution of 4″ × 4″, and generally show two or more
sources whose slowly evolving substructures have spatial scales
of 10″-30″. These maps were co-registered with Hα photographs
(courtesy of AF/AWS SOON, Holloman and Ramey AFB) to an accuracy of ±
8″. Similarly, the X-ray spectroheliograms have been co-registered
with white light photographs to about the same accuracy. Magnetograms
from KPNO and MSFC have also been co-aligned, and the magnetic X-ray,
and microwave features compared. In general we have found that (a)
the peaks of X-ray and 6 cm emission do not coincide, although (b) the
sources in the two wavelength domains tend to overlap. These facts in
themselves are evidence for the existence of opacity mechanisms other
than thermal bremsstrahlung. In order to quantify this assertion, we
have computed differential emission measures to derive densities and
temperatures. Using these and calculated force-free magnetic fields from
Kitt Peak magnetograms, we present an assessment of the mechanism of
gyroresonance absorption at low harmonics of the electron gyrofrequency
as the source of opacity responsible for the microwave features. We
conclude that large-scale currents must be present in the active region
loops to account for the bright 6 cm sources far from sunspots.
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Title: Transient Ionization Conditions in Solar Flares. Analysis of
High-Resolution X-Ray Spectra.
Authors: Schrijver, J.; Mewe, R.; Sylwester, J.; Strong, K. T.;
Bentley, R. D.
1982uxsa.collQ...4S Altcode: 1982IAUCo..73Q...4S
No abstract at ADS
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Title: Relationship between a soft X-ray long duration event and an
intense metric noise storm
Authors: Lantos, P.; Kerdraon, A.; Rapley, G. G.; Bentley, R. D.
1981A&A...101...33L Altcode:
An example of a soft X-ray long duration event associated with the
onset of a metric noise storm is reported. The event was observed by
the Nancay Radioheliograph, operating at a frequency of 169 MHz, and
the soft X-ray Polychromator experiment on board the Solar Maximum
Mission on March 30, 1980 in the solar active region 2363. The soft
X-ray event was found to exhibit all the features of a classical long
duration event, including an extensive system of loops forming over the
site of a disappearing H-alpha filament, H-alpha ribbons at the loop
footprints, a centrimetric rise and fall burst and a coronal white light
loop transient. The radio event detected simultaneously also displayed
typical noise storm characteristics, however was particularly intense,
extended over an unusually wide frequency range, and was located in
the northern leg of the loop transient. The possible association of
the southern leg of the loop transient with the long duration event
leads to the suggestion that it is the loop itself which provides the
physical link between the two events.
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Title: X-ray line widths and coronal heating
Authors: Acton, L. W.; Wolfson, C. J.; Joki, E. G.; Culhane, J. L.;
Rapley, C. G.; Bentley, R. D.; Gabriel, A. H.; Phillips, K. J. H.;
Hayes, R. W.; Antonucci, E.
1981ApJ...244L.137A Altcode:
Preliminary results of spectroscopy and imaging of a solar active region
and flare plasma in soft X-ray emission lines are presented. Observed
X-ray line widths in a nonflaring active region are broader than the
Doppler width corresponding to the local electron temperature. An
analysis of 41 soft X-ray flares within a single active region reveals
a preference for flares to occur at locations that already show
enhanced X-ray emission and to favor magnetic complexity over high
gradient. However, flares do not appear to be directly responsible
for the heating and X-ray production of the active regions.
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Title: Observations of the limb solar flare on 1980 April 30 with
the SMM X-ray polychromator
Authors: Gabriel, A. H.; Phillips, K. J. H.; Acton, L. W.; Wolfson,
C. J.; Culhane, J. L.; Rapley, C. G.; Bentley, R. D.; Kayat, M. A.;
Jordan, C.; Antonucci, E.
1981ApJ...244L.147G Altcode:
No abstract at ADS
---------------------------------------------------------
Title: X-ray spectra of solar flares obtained with a high-resolution
bent crystal spectrometer
Authors: Culhane, J. L.; Rapley, C. G.; Bentley, R. D.; Gabriel,
A. H.; Phillips, K. J.; Acton, L. W.; Wolfson, C. J.; Catura, R. C.;
Jordan, C.; Antonucci, E.
1981ApJ...244L.141C Altcode:
Preliminary results obtained for three solar flares with the bent
crystal spectrometer on the SMM are presented. Resonance and satellite
lines of Ca XIX and XVIII and Fe XXV and XXIV are observed together
with the Fe XXVI Lyman-alpha line. Plasma properties are deduced from
line ratios and evidence is presented for changes of line widths
coincident with the occurrence of a hard X-ray impulsive burst. Fe
K-alpha spectra from a disk center and a limb flare agree with the
predictions of a fluorescence excitation model. However, a transient
Fe K-alpha burst observed in a third flare may be explained by the
collisional ionization of cool iron by energetic electrons.
---------------------------------------------------------
Title: Active Region Magnetic Fields
Authors: Smith, J. B., Jr.; Strong, K. T.; Schmahl, E. J.; Kundu,
M. R.; Krall, K. R.; Bentley, R. D.
1981BAAS...13..881S Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Solar maximum mission experiment: Early results from the soft
X-ray polychromator experiment
Authors: Gabriel, A. H.; Antonucci, E.; Phillips, K. J. H.; Culhane,
J. L.; Bentley, R. D.; Parmar, A. N.; Rapley, C. G.; Acton, L. W.;
Leibacher, J. W.; Wolfson, C. J.; Strong, K. T.; Jordan, C.
1981AdSpR...1m.267G Altcode: 1981AdSpR...1Q.267G
The X-Ray Polychromator experiment has been in operation on the
SMM satellite for over three months. It is observing flares and
active regions in the wavelength range 1Å to 23Å using a number
of different modes. These include polychromatic imaging, high
resolution line profiles, high dispersion spectra, and light curves
with high time-resolution. Data are described together with some of
the preliminary analysis and interpretation.
---------------------------------------------------------
Title: Solar Maximum Mission experiment: early results from the soft
X-ray polychromator experiment.
Authors: Gabriel, A. H.; Culhane, J. L.; Acton, L. W.; Antonucci,
E.; Bentley, R. D.; Jordan, C.; Leibacher, J. W.; Parmar, A. N.;
Phillips, K. J. H.; Rapley, C. G.; Wolfson, C. J.; Strong, K. T.
1981hea..conf..267G Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Characteristics of Soft X-ray Long Duration Events Observed
by the SMM X-ray Polychromator
Authors: Bentley, R. D.; Rapley, C. G.
1980BAAS...12..904B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: A study of a soft X-ray slow event associated with the
commencement of a Type I noise storm
Authors: Rapley, C. G.; Bentley, R. D.; Lantos, P.; Kerdraon, A.
1980BAAS...12..912R Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Morphology of Active Region and Flares
Authors: Bentley, R. D.
1980BAAS...12..533B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The soft X-ray polychromator for the Solar Maximum Mission.
Authors: Acton, L. W.; Culhane, J. L.; Gabriel, A. H.; Bentley,
R. D.; Bowles, J. A.; Firth, J. G.; Finch, M. L.; Gilbreth, C. W.;
Guttridge, P.; Hayes, R. W.; Joki, E. G.; Jones, B. B.; Kent, B. J.;
Leibacher, J. W.; Nobles, R. A.; Patrick, T. J.; Phillips, K. J. H.;
Rapley, C. G.; Sheather, P. H.; Sherman, J. C.; Stark, J. P.; Springer,
L. A.; Turner, R. F.; Wolfson, C. J.
1980SoPh...65...53A Altcode:
The 1.4-22.4 Å range of the soft X-ray spectrum includes a multitude
of emission lines which are important for the diagnosis of plasmas
in the 1.5-50 million degree temperature range. In particular, the
hydrogen and helium-like ions of all abundant solar elements with Z
> 7 have their primary transitions in this region and these are
especially useful for solar flare and active region studies. The soft
X-ray polychromator (XRP) is a high resolution experiment working
in this spectral region. The XRP consists of two instruments with
a common control, data handling and power system. The bent crystal
spectrometer is designed for high time resolution studies in lines of Fe
I-Fe XXVI and Ca XIX. The flat crystal scanning spectrometer provides
for 7 channel polychromatic mapping of flares and active regions in
the resonance lines of O VIII, Ne IX, Mg XI, Si XIII, S XV, Ca XIX,
and Fe XXV with 14″ spatial resolution. In its spectral scanning
mode it covers essentially the entire 1.4-22.5 Å region.
---------------------------------------------------------
Title: The Mars penetrator telemetry and control system
Authors: Bentley, R. D.; Campbell, A. B.
1975isa..conf..324B Altcode:
A new method for exploring the planet Mars has been proposed that will
use ground-penetrating vehicles to carry scientific instruments below
the Martian surface. The subsurface performance of various sequences of
complicated experiments poses challenges in the design of the telemetry
and control links. This article describes the overall mission, the
penetrator, the constraints imposed by the mission and the penetrator,
and a design for the telemetry/control system. This design uses a
microprogrammed microprocessor; the sequences of commands are stored
in a Read-Only-Memory (ROM), and a particular sequence is initiated by
transmitting from the earth the address in the ROM that contains the
first of the commands for the specific sequence to be performed. Data
from the experiments are stored in a memory for later transmission
to an orbiter that serves as a relay station for the command and data
links with earth.