explanation      blue bibcodes open ADS page with paths to full text
Author name code: poland
ADS astronomy entries on 2022-09-14
author:"Poland, Arthur I." 

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Title: The Importance of Non-Isotropic Conduction in Multi-Dimensional
    MHD Calculations of Coronal Magnetic Loops
Authors: Poland, Arthur I.; Forjan, G.
2009SPD....40.1207P    Altcode:
  Much progress has recently been made in modeling and observations
  of coronal loops. Most recent modeling has focused on 1-D models
  to investigate the location of the heating responsible for the high
  temperatures of these loops and the corona in general. More specifically
  the focus has been on various forms of pulsed heating with much argument
  as to whether these pulses arise in the corona or the transition
  region. There has been very little work done using multi-dimensional
  models for two reasons: 1) to do this correctly one must treat thermal
  conduction in a non-isotropic manner, only along the magnetic field
  lines, and 2) to have the calculations be meaningful one must adequately
  resolve the transition region, to approximately 12 km resolution. We
  have addressed both of these problems in using the University of Chicago
  Flash code to model the solar atmosphere from a temperature of 8,000K
  to over 1,000,000K. Adequate resolution was achieved by setting the
  adaptive mesh parameter to a sufficiently large value that dynamic
  regridding gave the needed 12 km resolution. Thermal conduction was
  originally handled in the program as an isotropic quantity. However,
  we have developed new modules for the code such that conduction
  was calculated as occurring only along the magnetic field lines. <P
  />Preliminary results show that the 2-D results with non-isotropic
  conduction more closely match the 1-D results than the 2-D results with
  isotropic conduction. This indicates that 1-D calculations are still
  valuable. We also find that with sufficiently detailed observations
  one should be able to discriminate between heating originating in the
  transition region and heating originating in the corona.

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Title: Automated Detection of CMEs with SOHO and STEREO Coronagraph
    Observations
Authors: Olmedo, O.; Zhang, J.; Wechsler, H.; Poland, A.; Borne, K.
2008AGUSMSP43A..02O    Altcode:
  A Solar Eruptive Event Detection System (SEEDS) has been developed
  to automatically detect, track, and catalog coronal mass ejections
  (CMEs) with SOHO and STEREO corona observations. The method developed
  is based on decomposing 2-D Coronagraph images to 1-D and looking
  for outstanding bright regions. Thresholds determine these regions,
  and in time sequences, CMEs can be located and tracked. A complete
  catalog of CMEs using LASCO C2 coronagraphs has been compiled
  using the SEEDS software and the results are made available online
  (http://spaceweather.gmu.edu/seeds). A preliminary catalog has been
  made using SECCHI COR2 coronagraphs and is also available online. We
  have been experimenting with real-time detection and make these results
  available online on a daily basis. We present statistics comparing
  the detections made with LASCO C2 with the CDAW CME catalog for the
  whole solar cycle 23. It is found that SEEDS is able to identify
  approximately 75% of the CMEs found within the CDAW CME catalog
  (omitting CMEs with quality index of 0 indicating an ill-defined
  CME). We look into approximately 100% more events detected by SEEDS
  which were not in CDAW and study the nature of these events.

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Title: Automatic Detection and Tracking of Coronal Mass Ejections
    in Coronagraph Time Series
Authors: Olmedo, O.; Zhang, J.; Wechsler, H.; Poland, A.; Borne, K.
2008SoPh..248..485O    Altcode: 2008SoPh..tmp....6O
  We present the current capabilities of a software tool to automatically
  detect coronal mass ejections (CMEs) based on time series of coronagraph
  images: the solar eruptive event detection system (SEEDS). The software
  developed consists of several modules: preprocessing, detection,
  tracking, and event cataloging. The detection algorithm is based on
  a 2D to 1D projection method, where CMEs are assumed to be bright
  regions moving radially outward as observed in a running-difference
  time series. The height, velocity, and acceleration of the CME are
  automatically determined. A threshold-segmentation technique is applied
  to the individual detections to automatically extract an approximate
  shape of the CME leading edge. We have applied this method to a
  12-month period of continuous coronagraph images sequence taken at
  a 20-minute cadence by the Large Angle and Spectrometric Coronagraph
  (LASCO) instrument (using the C2 instrument only) onboard the Solar
  and Heliospheric Observatory (SOHO) spacecraft. Our automated method,
  with a high computational efficiency, successfully detected about
  75% of the CMEs listed in the CDAW CME catalog, which was created by
  using human visual inspection. Furthermore, the tool picked up about
  100% more small-size or anomalous transient coronagraph events that
  were ignored by human visual inspection. The output of the software
  is made available online at http://spaceweather.gmu.edu/seeds/. The
  parameters of scientific importance extracted by the software package
  are the position angle, angular width, velocity, peak, and average
  brightness. Other parameters could easily be added if needed. The
  identification of CMEs is known to be somewhat subjective. As our
  system is further developed, we expect to make the process significantly
  more objective.

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Title: The Advancement Of An Automatic Solar Eruptive Event Detection
    System (seeds) To A Near Real-time System
Authors: Olmedo, Oscar; Zhang, J.; Wechsler, H.; Poland, A.; Borne, K.
2007AAS...210.2929O    Altcode: 2007BAAS...39..325O
  We have been working on a tool to automatically detect, track and
  catalogue Coronal Mass Ejections as observed by the LASCO C2 instrument
  on board the SOHO spacecraft. The software developed follows a simple
  algorithm, which is based on decomposing 2-D Coronagraph images to 1-D
  and looking for outstanding bright regions. Thresholds determine these
  regions, and in time sequences, CMEs can be located and tracked. Many
  improvements to the algorithm have been made in recent months dealing
  with the preprocessing of the input images as well as the tracking of
  CME detections. Most importantly the system has advanced to the point
  that it can make detections of CMEs in near real-time. What is meant
  by near real-time detection is; first, the downloading images, as they
  are made available by the instrument team, and second, the processing
  and reporting of CME events as they occur on a daily basis. The true
  positive rate of detections is over 75% as compared with the CDAW CME
  catalog, and will continue to improve with further experimentation
  of threshold values. Output from the SEEDS algorithm can be found
  at http://solar.gmu.edu/research/autocme/ (Still showing preliminary
  results). Currently, the software is being adapted to accept STEREO
  images as input, preliminary test with STEREO COR2 data show promising
  results.

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Title: Sentinels of the Sun: Forecasting Space Weather
Authors: Poland, Arthur I.
2006SpWea...4.8007P    Altcode:
  The story of humanity's interest in space weather may go back to
  prehistoric times when people at high latitudes noticed the northern
  lights. Interest became more acute after the development of electrical
  technologies such as the telegraph, and certainly during World War
  II when shortwave radio communication came into practical use. Solar
  observing actually began to be supported by the military, with the
  observatory at Climax, Colorado being established to monitor the Sun
  during the war. With the advent of satellites and manned space travel
  to the Moon, space weather became a seriously funded endeavor both for
  basic research and forecasting. In the book, Sentinels of the Sun:
  Forecasting Space Weather, Barbara Poppe does an excellent job of
  telling this story for the nonprofessional. Moreover, as a professional
  who has studied space weather since before humans landed on the Moon,
  I found the book to be a very enjoyable read.

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Title: The Development of an Automatic Solar Eruptive Event Detection
    System (SEEDS)
Authors: Olmedo, Oscar A., Jr.; Zhang, J.; Wechsler, H.; Borne, K.;
   Poland, A.
2006SPD....37.0817O    Altcode: 2006BAAS...38..233O
  We present a software tool that automatically detects Coronal Mass
  Ejections (CMEs) as observed by the LASCO C2 instrument on board the
  SOHO spacecraft. The software developed follows a simple algorithm,
  which is based on decomposing 2-D Coronagraph images to 1-D and
  looking for outstanding bright regions. Thresholds determine these
  regions, and in time sequences, CMEs can be located and tracked. We
  have applied this method on a 12-month period of LASCO C2 data and
  have found about 75% more events than the NRL-GSFC-CUA CME catalog
  generated by human visual inspection. The automatic method gives a
  true positive rate of approximately 75% using the manual catalog as
  a benchmark. The software being presented is to be part a suite of
  software tools in the Solar Eruptive Event Detection System (SEEDS),
  being developed at George Mason University. The main purpose of SEEDS
  is to make associations of solar transient events observed by different
  instruments based on high-dimensional temporal and spatial data. An
  example problem SEEDS may be able to answer is whether or not a CME
  event seen In a Coronagraph is associated with a flareing/dimming
  event seen in coronal images. With many future spac missions underway,
  such as STEREO and SDO, SEEDS hopes to be utilized in aiding to the
  gain of scientific knowledge in an efficient and effective way, to the
  ultimate goal of making real time forecasting of space weather events.

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Title: Automatic detection of Coronal Mass Ejections using Computer
    Vision.
Authors: Olmedo, O. A.; Zhang, J.; Wechsler, H.; Poland, A.; Borne,
   K. D.
2006AGUSMSH43A..02O    Altcode:
  We present a software tool that automatically detects Coronal Mass
  Ejections (CMEs) as observed by the LASCO C2 instrument on board the
  SOHO spacecraft. The software developed follows a simple algorithm,
  which is based on decomposing 2-D Coronagraph images to 1-D and
  looking for outstanding bright regions. Thresholds determine these
  regions, and in time sequences, CMEs can be located and tracked. We
  have applied this method on a 12-month period of LASCO C2 data and
  have found about 75% more events than the NRL-GSFC-CUA CME catalog
  generated by human visual inspection. The automatic method gives a
  true positive rate of approximately 75% using the manual catalog as
  a benchmark. The software being presented is to be part a suite of
  software tools in the Solar Eruptive Event Detection System (SEEDS),
  being developed at George Mason University. The main purpose of SEEDS
  is to make associations of solar transient events observed by different
  instruments based on high-dimensional temporal and spatial data. An
  example problem SEEDS may be able to answer is whether or not a CME
  event seen In a Coronagraph is associated with a flareing/dimming
  event seen in coronal images. With many future spac missions underway,
  such as STEREO and SDO, SEEDS hopes to be utilized in aiding to the
  gain of scientific knowledge in an efficient and effective way, to the
  ultimate goal of making real time forecasting of space weather events.

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Title: Heating the Solar Corona: Observations for Model Boundary
    Conditions
Authors: Nestlerode, C. M.; Poland, A. I.
2005AAS...20711107N    Altcode: 2005BAAS...37.1342N
  A prominent question in solar physics concerns the sources of coronal
  heating. This problem can be addressed through observations of closed
  magnetic loops which have high enough density to provide adequate
  temporal, spatial, and spectral resolution. Measurements of temperature,
  density, and velocity throughout the loop can be used for boundary
  conditions and compared with quantities for model calculations. In
  this paper, we present Solar Ultraviolet Measurements from Emitted
  Radiation (SUMER) data from the Solar and Heliospheric Observatory's
  (SOHO's) JOP 161 program. The SUMER instrument has high spatial and
  spectral resolution over several different spectral lines and therefore
  the data cover a large temperature range. The analyzed lines include
  Mg VIII, Mg IX, N III, N IV, Ne VIII, O IV, O V, S IV, S V, and S X
  with temperatures ranging from 60,000 K (S IV) to 0.9 MK (Mg IX). The
  velocity profiles are created using Gaussian fitting with wavelength
  calibration determined using average quiet Sun velocities from known
  Doppler velocity shifts. The velocity profiles show important changes
  in solar foot point plasma speed both spatially and temporally. This
  analysis builds on previous analysis of solar spectral lines observed
  with the SOHO Coronal Diagnostic Spectrometer (CDS); the advantage
  of the SUMER instrument is better resolution, both spectrally and
  spatially. This work was funded by NASA, Living with a Star Program.

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Title: Solar Eruptive Event Detection System (SEEDS)
Authors: Olmedo, O.; Zhang, J.; Wechsler, H.; Borne, K.; Poland, A.
2005AAS...20711106O    Altcode: 2005BAAS...37.1342O
  We report the progresses in developing a suite of software tools
  to automatically detect and classify transient astrophysical
  events. Astrophysical data is being created at the rate beyond human
  operators capable of analyzing. Our team, composed of scientist in the
  astronomy and computer science departments at George Mason University
  (GMU), is particularly interested in tackling this problem. This project
  is in its early stage and to date we are concentrating on solar eruptive
  events, calling our analyzing scheme Solar Eruptive Event Detection
  System (SEEDS). We have successfully developed tools to detect and
  classify coronal mass ejections (CMEs) observed by LASCO instrument on
  board the SOHO spacecraft. SEEDS proceeds as follows; firstly advanced
  image processing techniques are used to detect transient features and a
  time-dependent causal filter is applied for tracking the features, from
  here, the detected events are put through a machine learning algorithm
  where they are classified and event catalogs are created. The next
  step is to make association of transient events observed by different
  instruments based on high-dimensinal temporal and spatial data. A
  scientific question, for example, that may be answered with SEES is
  whether or not a CME event seen in a Coronagraph is associated with a
  flareing/dimming event seen in coronal images. With many future space
  observing missions underway, such as STEREO and SDO, SEEDS hopes to be
  utilized in aiding to the gain of scientific knowledge in an efficient
  and effective way, to the ultimate goal of making real time forecasting
  of space weather events.

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Title: Space Weather At George Mason University
Authors: Poland, A. I.; Zhang, J.
2005AGUSMED11A..04P    Altcode:
  George Mason University (GMU), located in Fairfax, Virginia has an
  exciting and rapidly growing set of graduate programs in Astrophysics,
  Space Weather, Planetary Sciences, and Earth Sciences. The faculty
  members in these programs are affiliated with the Department of Physics
  and Astronomy and the School of Computational Sciences (SCS). The
  synergy between these two departments creates opportunities for
  learning not found in traditional programs. Our curriculum emphasizes
  multi-disciplinary science that crosses traditional department
  boundaries. Space Weather/solar terrestrial physics is one of these
  multi-disciplinary areas. We expect our students to develop a deep
  understanding of the Sun, the heliosphere, geospace, and their
  interactions; we emphasize a systems view. The graduate program in
  Space Weather at GMU offers degrees at the Masters (M.S.) and Doctoral
  (Ph. D) levels through the School of Computational Sciences (SCS)
  and the Department of Physics and Astronomy of the College of Arts and
  Sciences (CAS). A wide variety of relevant courses are offered through
  (SCS) in partnership with (CAS). Students also have the opportunity to
  do research associated with the Goddard Space Flight Center and the
  Navel Research Laboratory. For more information on the program see:
  http://www.scs.gmu.edu/spaceweather/ Undergraduates and people from
  local industry are also taking some of our courses to further their
  education in this area. Many of them are finding the lectures directly
  relevant to their daily work, such as satellite orbit maintenance.

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Title: Doppler Shift Velocity Calculations of Multi-Wavelength Coronal
    Diagnostic Spectrometer Data Using Various Background Corrections
Authors: Duffin, R. T.; Poland, A. I.; McIntosh, S. W.
2004ESASP.575..545D    Altcode: 2004soho...15..545D
  No abstract at ADS

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Title: Detailed SUMER Observations of Coronal Loop Footpoint Dynamics
Authors: McIntosh, Scott W.; Poland, Arthur I.
2004ApJ...604..449M    Altcode:
  For the most part, the characteristics of heating in the open corona
  and in closed coronal loops are determined by observing the emitted
  plasma intensity as a function of position and comparing this with
  model calculations. There are also some efforts that include observed
  velocity and still others that use theoretical physical processes
  such as electrodynamic or turbulent heating, for example. With a
  view toward future modeling endeavors, we investigate the temporal
  behavior of the intensity and velocity of a magnetic loop footpoint
  as observed by SUMER on the Solar and Heliospheric Observatory (SOHO)
  spacecraft as part of SOHO/TRACE Joint Observing Program 72. We study
  these quantities in emission lines that were specifically chosen to
  span the temperature domain of the upper chromospheric and transition
  region plasmas (10<SUP>5</SUP>-10<SUP>6</SUP> K). We discuss the
  implications of these observations, suggest improvements, and present
  some new avenues of exploration. The most significant result is the
  demonstration of the importance of including the measurement of velocity
  as a function of time in the loop footpoint region.

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Title: International heliophysical year: a program of global research
    continuing the tradition of previous international years
Authors: Davila, Joseph M.; Poland, Arthur I.; Harrison, Richard A.
2004AdSpR..34.2453D    Altcode:
  In 1957 a program of international research, inspired by the
  International Polar Years of 1882-1883 and 1932-1933, was organized
  as the International Geophysical Year (IGY) to study global phenomena
  of the Earth and geospace. The IGY involved about 60,000 scientists
  from 66 nations, working at thousands of stations from pole to pole,
  in an effort to obtain simultaneous, global observations on Earth
  and in space. There had never been anything like it before. The 50th
  anniversary of the International Geophysical Year will occur in 2007. We
  propose to organize an international program of scientific collaboration
  for this time period called the International Heliophysical Year
  (IHY). Like its predecessors, the IHY will focus on fundamental global
  questions of Earth science.

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Title: Nonlinear interactions in coronal heating
Authors: Einaudi, G.; Dahlburg, R. B.; Rappazzo, A. F.; Poland, A.;
   Li, Y.
2004cosp...35.3938E    Altcode: 2004cosp.meet.3938E
  The dynamics of the solar corona as well as its very existence are
  due to the dynamics of plasmas and magnetic fields which, at the
  global scales of coronal loops, prominences and helmet streamers
  may be described by magnetohydrodynamics. Here we will discuss the
  importance and role of nonlinear interactions in the heating of the
  solar corona, which relies on the transfer, storage and dissipation of
  the mechanical energy present in photospheric motion (Einaudi and Velli
  1999). Nonlinear interactions including the coupling of coronal fields
  to the motions and emerging flux through the photosphere determine both
  the rate of heating and the topology of coronal magnetic fields. The
  dependence of the heating rate on the time and space scales of the
  photospheric motions will be considered. In particular we compare the
  results of the numerical simulations performed using as input the MDI
  data on the features of the photospheric motions at the base of some
  coronal loops with the behavior of the loops themselves as deduced
  from TRACE. G. Einaudi and M. Velli, Phys. Plasmas 6, 4146 (1999).

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Title: Road Map of Solar-Terrestrial Programs in the USA
Authors: Poland, A. I.
2003JKAS...36S.151P    Altcode:
  No abstract at ADS

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Title: Coronal Loops Heated by Magnetohydrodynamic Turbulence. I. A
    Model of Isobaric Quiet-Sun Loops with Constant Cross Sections
Authors: Chae, Jongchul; Poland, Arthur I.; Aschwanden, Markus J.
2002ApJ...581..726C    Altcode:
  Several recent papers have presented new observational results
  indicating that many coronal loops in active regions are nearly
  isothermal. It is expected that quiet-Sun loops may have similar thermal
  structures, since quiet-Sun differential emission measures look similar
  to those in active regions. In the quiet Sun, it is well known from
  observations that the nonthermal velocity inferred from the excess
  broadening of a line over thermal broadening reaches a peak of about
  30 km s<SUP>-1</SUP> around 3×10<SUP>5</SUP> K and then decreases
  with temperature, having a value of about 20 km s<SUP>-1</SUP> at
  1×10<SUP>6</SUP> K. In the present work, we make the assumption
  that the observed nonthermal velocities are a manifestation of
  magnetohydrodynamic (MHD) turbulence and present a model of static,
  isobaric coronal loops heated by turbulence. Instead of solving the
  MHD equations, we adopt simple energy spectra in MHD turbulence and
  infer the heating rate as a function of temperature from the observed
  nonthermal velocities. By solving the steady state energy equation
  of a loop in which temperature monotonically increases with height,
  we obtain the following results: (1) The heating rate is predominantly
  near the footpoints and decreases with the loop arc length. (2) There
  is a critical temperature above which the loop cannot be maintained
  in a steady state. (3) The loop is denser and is more isothermal than
  uniformly heated loops, being compatible with recent observations. (4)
  The theoretical differential emission measures are in good agreement
  with the empirical values at temperatures above 10<SUP>5</SUP> K. Below
  this temperature, we still have a large discrepancy. (5) It is possible
  to explain the observed strong correlation between intensity and
  nonthermal velocity of a spectral line in the quiet Sun. Our results
  support the idea that quasi-statically driven MHD turbulence of the
  direct current (DC) type in the stratified medium (transition region
  and corona) is a viable mechanism for coronal heating.

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Title: The International Heliophysical Year (IHY)
Authors: Davila, J. M.; Harrison, R.; Poland, A.; Thompson, B.;
   Gopalswamy, N.
2002AGUFMSH21A0518D    Altcode:
  In 1957 a program of international research, inspired by the
  International Polar Years of 1882-83 and 1932-33, was organized as
  the International Geophysical Year (IGY) to study global phenomena of
  the Earth and geospace. The IGY involved about 60,000 scientists from
  66 nations, working at thousands of stations, from pole to pole to
  obtain simultaneous, global observations on Earth and in space. There
  had never been anything like it before. The fiftieth anniversary of
  the International Geophysical Year will occur in 2007. We propose to
  organize an international program of scientific collaboration for this
  time period called the International Heliophysical Year (IHY). Like
  it predecessors, the IHY will focus on fundamental global questions
  of Earth science.

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Title: The International Heliophysical Year Concept
Authors: Davila, J.; Harrison, R.; Poland, A.; St-Cyr, O.; Thompson, B.
2002cosp...34E.529D    Altcode: 2002cosp.meetE.529D
  In 1957 a program of international research, inspired by the
  International Polar Years of 1882-83 and 1932-33, was organized as
  the International Geophysical Year (IGY) to study global phenomena of
  the Earth and geospace. The IGY involved about 60,000 scientists from
  66 nations, working at thousands of stations, from pole to pole to
  obtain simultaneous, global observations on Earth and in space. There
  had never been anything like it before. The fiftieth anniversary of
  the International Geophysical Year will occur in 2007. We propose to
  organize an international program of scientific collaboration for this
  time period called the International Heliophysical Year (IHY). Like
  its predecessors, the IHY will focus on fundamental global questions
  of Earth science.

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Title: The New Solar Corona
Authors: Aschwanden, Markus J.; Poland, Arthur I.; Rabin, Douglas M.
2001ARA&A..39..175A    Altcode:
  We focus on new observational capabilities (Yohkoh, SoHO,
  TRACE), observations, modeling approaches, and insights into
  physical processes of the solar corona. The most impressive new
  results and problems discussed in this article can be appreciated
  from the movies available on the Annual Reviews website and at
  http://www.lmsal.com/pub/araa/araa.html. "The Sun is new each
  day." Heraclites (ca 530-475 BC) "Everything flows." Heraclites (ca
  530-475 BC)

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Title: Technology for the SEC Theme at NASA
Authors: Poland, A. I.
2000SPD....31.1604P    Altcode: 2000BAAS...32..849P
  Technology advances are essential to achieve a high quality of science
  in NASA missions. In the past, instrument technology has been funded
  either through the SR&amp;T program or during development of accepted
  flight programs. Some changes are occuring in NASA to improve our
  ability to advance technology for our future programs. I will discuss
  some of the new program ideas and relate them to the SEC Roadmap and
  other SEC technology documents being developed at GSFC.

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Title: Four years of SOHO discoveries - some highlights.
Authors: Fleck, B.; Brekke, P.; Haugan, S.; Duarte, L. S.; Domingo,
   V.; Gurman, J. B.; Poland, A. I.
2000ESABu.102...68F    Altcode:
  Analysis of the helioseismic data from SOHO has shed new light on
  solar and heliosheric physics: the structure and dynamics of the
  solar interior, the heating and dynamics of the solar corona, and the
  acceleration and composition of the solar wind.

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Title: Modeling of Solar Transition Region Outflows
Authors: Poland, A. I.; Chae, J.
1999AAS...194.9312P    Altcode: 1999BAAS...31..990P
  The problem of observing outflow of material from the Sun has been an
  interesting issue in solar physics for several decades. The problem is
  that we know material flows from the Sun since there is a solar wind
  measured at Earth and in interplanetary space. However, observations in
  the chromosphere, transition region, and lower corona show mostly inflow
  with almost no outflow. In a recent paper by Hassler and coworkers it
  was shown that there is a significant outflow at network boundaries
  as seen in NeVIII (Te 800,000K), but no significant outflows have been
  observed at other temperatures. In our earlier work we demonstrated why
  one would expect to see only inflows below 100,000K. The energy balance
  between conduction, radiation, and enthalpy resulted in gradients
  being too steep to observe outflowing material. We have extended that
  work to 1,000,000K and included the observed effects of the spreading
  magnetic field with temperature. These new calculation results seem
  to be in agreement with the observations and indicate that outflows
  should only be observable in the 800,000K range.

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Title: Observations of Hydrogen and Helium Continua in Solar
    Prominences
Authors: Andretta, V.; Kucera, T. A.; Poland, A. I.
1999ASPC..158..162A    Altcode: 1999ssa..conf..162A
  No abstract at ADS

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Title: Active Regions
Authors: Holman, G. D.; Cheng, C. -C.; Gurman, J. B.; Haisch, B. M.;
   Poland, A. I.; Porter, J. G.; Saba, J. L. R.; Schmieder, B.; Strong,
   K. T.
1999mfs..conf...41H    Altcode:
  Magnetic Field Strength and Strucutre Results Prior to SMM First Results
  with SMM Subsequent Results: 1983-1987 The Coronal Magnetic Structures
  Observing Campaign Coronal Magnetic Field Studies after SMM Dynamics
  and Heating of the Solar Corona FCS Line-Broadening Measurements
  Large Nonthermal Velocities Spatial Variations Correlation Studies FCS
  Line-Broadening Data Interpreting the FCS Line Broadening Constraints
  on Mass Motions Link to Heating Discussion Coronal Heating, Magnetic
  Fields, and Flares UVSP Obervations of Active Regions Transition Region
  Brightenings: UV Microflares Sunspots Magnetic Field and Height of the
  Transition Region Sunspot Plumes Sunspot Flows Horizontal Flows Vertical
  Flows Nonthermal Line Broadening Umbral Oscillations A Look Backward,
  a Look Forward Prominences and Filaments Prominence Environment and
  Structure Steady Flows in Prominence Material Activity in Prominences
  Postflare Loops and Surges Conclusion

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Title: Neutral Hydrogen Column Depths in Prominences Using EUV
    Absorption Features
Authors: Kucera, T. A.; Andretta, V.; Poland, A. I.
1998SoPh..183..107K    Altcode:
  Observations of prominence regions in hot coronal lines (≳106 K)
  at wavelengths below the hydrogen Lyman absorption limit show what
  appear to be absorption features. Other authors have suggested that
  these observed features may be due to H and He continuum absorption. But
  there has, as yet, been no conclusive evidence that this is indeed the
  case. In this paper we present new Solar and Heliospheric Observatory
  (SOHO) observations that allow us to address this problem in a
  quantitative manner. We find that continuum absorption is the best
  explanation for the absorption observed in imaging data from the Coronal
  Diagnostic Spectrometer (CDS) on board SOHO. Furthermore, we discuss
  a new technique to measure the column depth of neutral hydrogen in a
  prominence, and use it to obtain estimates of the prominence filling
  factors as well. We calculate the column depth of neutral hydrogen,
  ξH∼1018 cm−2, and the filling factor, f≳0.3.

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Title: SUMER Observations of the Evolution and the Disappearance of
    a Solar Prominence
Authors: Ofman, L.; Kucera, T. A.; Mouradian, Z.; Poland, A. I.
1998SoPh..183...97O    Altcode:
  The mechanisms that lead to the formation and the disappearance of
  prominences are poorly understood, at present. An arch-shaped prominence
  was observed with the Solar Ultraviolet Measurements of Emitted
  Radiation (SUMER) spectrometer on board the Solar and Heliospheric
  Observatory (SOHO) on 31 March-1 April 1996. The observations were
  performed at three wave-bands in the Lyman continuum. Ten successive
  images were obtained at 41-minute time intervals. Based on computed
  models of Gouttebroze, Heinzel, and Vial (1993), we have determined the
  temperature distribution of the prominence using the intensity ratio of
  876 Å and 907 Å. The observed time sequence shows that parts of the
  prominence disappear possibly by heating, while other parts exhibit
  heating and cooling with apparent outward motion. We model the heat
  input with the linearized MHD equations using a prescribed initial
  density and a broad-band spectrum of Alfvén waves. We find a good
  qualitative agreement with observations. In the model the prominence
  is heated by the resonant absorption of Alfvén waves with frequencies
  that match the resonant condition for a particular flux tube structure
  that is determined by the magnetic field topology and plasma density.

---------------------------------------------------------
Title: Temperature Dependence of Ultraviolet Line Average Doppler
    Shifts in the Quiet Sun
Authors: Chae, J.; Yun, H. S.; Poland, A. I.
1998ApJS..114..151C    Altcode:
  The existence of prevailing redshifts in the UV lines formed in the
  solar transition region raises an important question concerning its
  physical origin and its role in the mass and energy balance of the
  outer solar atmosphere. A series of UV spectral lines observed by
  SUMER has been analyzed to obtain the spatial average of Doppler
  shifts in the quiet Sun as a function of temperature. The UV lines
  used for the analysis cover temperatures ranging from 10<SUP>4</SUP>
  to 10<SUP>6</SUP> K. The wavelength calibration has been done in
  reference to the coolest chromospheric lines such as neutral lines
  of silicon and sulfur. The positioning of the line center in blended
  lines has been made by employing a constrained multi-Gaussian fitting
  technique. The error in the measured average of the Doppler shifts is
  estimated to be smaller than 1 km s<SUP>-1</SUP>. <P />Our results show
  that the average Doppler shift at the base of the transition region is
  about 1-2 km s<SUP>-1</SUP>, increasing with temperature with a peak
  value of 11 km s<SUP>-1</SUP> near T = 2.3 × 10<SUP>5</SUP> K. Then
  it decreases but remains still above zero (5 km s<SUP>-1</SUP> in
  Ne VIII lines and 4 km s<SUP>-1</SUP> in Mg X lines). We find that
  this behavior can be explained by the dominance of emission from
  plasma flowing downward from the upper hot region to the lower cool
  region along flux tubes with varying cross section. Assuming that
  pressure and mass flux are constant along a flux tube, the cross
  section of a typical flux tube has been estimated as a function of
  temperature. It turns out that the cross section is nearly constant
  below T = 10<SUP>5</SUP> K and then expands by a factor of about 30 at
  T = 10<SUP>6</SUP> K. This behavior is fairly well represented by an
  analytical functional form, A(T)/A(T<SUB>h</SUB>) = [1 + (Γ<SUP>2</SUP>
  - 1)(T/T<SUB>h</SUB>)<SUP>ν</SUP>]<SUP>1/2</SUP>/Γ with parameters
  of T<SUB>h</SUB> = 10<SUP>6</SUP> K, Γ = 30, and ν = 3.6.

---------------------------------------------------------
Title: Helio-Atmospheric Links Explorer (HALE): A MIDEX Experiment
    for Exploring the Emergence of Magnetic Flux from Below the Solar
    Photosphere through the Corona
Authors: Scherrer, P. H.; Title, A. M.; Bush, R. I.; Duvall, T. L.,
   Jr.; Gurman, J. B.; Kosovichev, J. T.; Hoeksema, A. G.; Poland, A. I.;
   Tarbell, T. D.
1998ESASP.417..285S    Altcode: 1998cesh.conf..285S
  No abstract at ADS

---------------------------------------------------------
Title: Helical Structure in an Eruptive Prominence Related to a CME
    (SUMER, CDS, LASCO)
Authors: Kucera, T. A.; Poland, A. I.; Wiik, J. E.; Schmieder, B.;
   Simnett, G.
1998ASPC..150..318K    Altcode: 1998IAUCo.167..318K; 1998npsp.conf..318K
  SOHO (SUMER/CDS) observed an eruptive prominence on May 1,1996,
  associated with a CME observed by LASCO. We investigate the
  physical conditions of this prominence in order to quantify velocity,
  temperature, and density. SUMER spectra in Si IV and O IV lines are used
  to obtain Doppler-shift images of the prominence. The prominence shows
  large-scale red and blueshifted regions, revealing a large helical
  structure with a global twist. In addition, fine structure analysis
  shows multiple components in the line profile, suggesting integration
  of many threads along the line-of-sight with a large dispersion of
  velocities (∼150 km s<SUP>-1</SUP>).

---------------------------------------------------------
Title: Dynamics and Fine Structures in Quiescent Prominences (MSDP/Pic
    du Midi, SOHO/SUMER and CDS)
Authors: Li, K.; Malherbe, J. -M.; Wiik, J. E.; Schmieder, B.; Roudier,
   Th.; Kucera, T.; Poland, A.
1998ASPC..150...32L    Altcode: 1998IAUCo.167...32L; 1998npsp.conf...32L
  No abstract at ADS

---------------------------------------------------------
Title: Observation of Prominence Heating and the Heating Mechanism
Authors: Ofman, L.; Mouradian, Z.; Kucera, T. A.; Poland, A. I.
1998ASPC..150..159O    Altcode: 1998IAUCo.167..159O; 1998npsp.conf..159O
  No abstract at ADS

---------------------------------------------------------
Title: Velocity Fields of a Filament Region Observed with Ground-Based
    Telescopes and from SOHO
Authors: Mein, P.; Schmieder, B.; Malherbe, J. -M.; Wiik, J. E.;
   Engvold, O.; Brekke, P.; Zirker, J. B.; Poland, A. I.; Delaboudiniere,
   J. -P.; Staiger, J.
1998ASPC..150..135M    Altcode: 1998npsp.conf..135M; 1998IAUCo.167..135M
  No abstract at ADS

---------------------------------------------------------
Title: Eruptive prominence and associated CME observed with SUMER,
    CDS and LASCO (SOHO)
Authors: Wiik, J. E.; Schmieder, B.; Kucera, T.; Poland, A.; Brekke,
   P.; Simnett, G.
1997SoPh..175..411W    Altcode:
  Observations of an eruptive prominence were obtained on 1 May 1996,
  with the SUMER and CDS instruments aboard SOHO during the preparatory
  phase of the Joint Observing Programme JOP12. A coronal mass ejection
  observed with LASCO is associated temporally and spatially with this
  prominence. The main objective of JOP12 is to study the dynamics of
  prominences and the prominence-corona interface. By analysing the
  spectra of Oiv and Siiv lines observed with SUMER and the spectra of
  15 lines with CDS, Doppler shifts, temperatures and electron densities
  (ratio of Oiv 1401 to 1399Å) were derived in different structures of
  the prominence. The eruptive part of the prominence consists of a bubble
  (plasmoid) of material already at transition region temperatures with
  red shifts up to 100 km s<SUP>-1</SUP> and an electron density of the
  order of 10<SUP>10</SUP>cm<SUP>-3</SUP>. The whole prominence was very
  active. It developed both a large helical loop and several smaller loops
  consisting of twisted threads or multiple ropes. These may be studied
  in the SUMER movie (movie 2). The profiles of the SUMER lines show a
  large dispersion of velocities (±50 km s<SUP>-1</SUP>) and the ratio
  of the Oiv lines indicates a large dispersion in electron density (3 x
  10<SUP>9</SUP>cm<SUP>-3</SUP> to 3x 10<SUP>11</SUP>cm<SUP>-3</SUP>). The
  CME observed by LASCO left the corona some tens of minutes before the
  prominence erupted. This is evidence that the prominence eruptions are
  probably the result of the removal of the restraining coronal magnetic
  fields which are in part responsible for the original stability of
  the prominence.

---------------------------------------------------------
Title: Effects of Non-LTE Radiative Loss and Partial Ionization on
    the Structure of the Transition Region
Authors: Chae, J.; Yun, H. S.; Poland, A. I.
1997ApJ...480..817C    Altcode:
  In this paper we address the question of how non-LTE radiative losses
  with partial ionization of hydrogen and helium affects the energetics
  and structure of the solar transition region. To accomplish this we
  have constructed theoretical models of a thin rigid magnetic flux
  tube with a steady material flow, which is embedded vertically in
  the solar atmosphere. These models include the effects of material
  flow, conduction, non-LTE radiative transfer in H and He, and partial
  ionization. We find from this study that the effect of non-LTE radiative
  transfer with partial ionization is significant near the base of the
  transition region at temperatures less than 2.5 × 10<SUP>4</SUP>
  K. This leads to a 1 order of magnitude increase in the differential
  emission measure in comparison with the optically thin approximation
  with complete ionization in the low (less than 2.5 × 10<SUP>4</SUP> K)
  temperature regime. Above this region the non-LTE and opacity effects
  are small. In the upflow case the conductive and convective energy
  processes dominate to such a large extent that non-LTE radiative
  process and partial ionization are not important. <P />In this work
  we also confirm the previous work of other authors who provided the
  explanation for why downflowing transition region material is much
  more visible than upflowing material. We present the results in a
  manner that gives a good physical understanding as to why this occurs.

---------------------------------------------------------
Title: Measuring the He I/H ratio in a prominence using Lyman
    absorption
Authors: Kucera, T. A.; Andretta, V.; Poland, A. I.
1997SPD....28.0112K    Altcode: 1997BAAS...29Q.881K
  We investigate a method for measuring the ratio of neutral helium to
  hydrogen in solar prominences. The upper limit to the Lyman continuum
  occurs at 911 Angstroms for H, 504 Angstroms for He I, and 228 Angstroms
  for He II. Lyman absorption by prominences and other structures is
  clearly visible in emission of hot coronal lines observed by the Coronal
  Diagnostic Spectrometer (CDS) and Extreme Ultraviolet Imaging Telescope
  (EIT) aboard the Solar and Heliospheric Observatory (SOHO). By comparing
  the absorption in lines absorbed by H only and by H and He I, the ratio
  of He I to H in prominences can be determined. We attempt to do this
  by comparing the absorption by a prominence in the Mg X line at 624.9
  Angstroms and the Mg IX line at 368.1 Angstroms, both observed by CDS.

---------------------------------------------------------
Title: A New Look at the Quiet Sun Network in the Upper Atmosphere
    During a Minimum of Activity Cycle
Authors: Lemaire, P.; Schuehle, U.; Curdt, W.; Wilhelm, K.; Poland,
   A.; Falciani, R.
1997ESASP.404..517L    Altcode: 1997cswn.conf..517L
  No abstract at ADS

---------------------------------------------------------
Title: First Results of the SUMER Telescope and Spectrometer on SOHO -
    I. Spectra and Spectroradiometry
Authors: Wilhelm, K.; Lemaire, P.; Curdt, W.; Schühle, U.; Marsch, E.;
   Poland, A. I.; Jordan, S. D.; Thomas, R. J.; Hassler, D. M.; Huber,
   M. C. E.; Vial, J. -C.; Kühne, M.; Siegmund, O. H. W.; Gabriel, A.;
   Timothy, J. G.; Grewing, M.; Feldman, U.; Hollandt, J.; Brekke, P.
1997SoPh..170...75W    Altcode:
  SUMER - the Solar Ultraviolet Measurements of the Emitted Radiation
  instrument on the Solar and Heliospheric Observatory (SOHO) - observed
  its first light on January 24, 1996, and subsequently obtained a
  detailed spectrum with detector B in the wavelength range from 660
  to 1490 Å (in first order) inside and above the limb in the north
  polar coronal hole. Using detector A of the instrument, this range
  was later extended to 1610 Å. The second-order spectra of detectors
  A and B cover 330 to 805 Å and are superimposed on the first-order
  spectra. Many more features and areas of the Sun and their spectra
  have been observed since, including coronal holes, polar plumes and
  active regions. The atoms and ions emitting this radiation exist at
  temperatures below 2 × 10<SUP>6</SUP> K and are thus ideally suited
  to investigate the solar transition region where the temperature
  increases from chromospheric to coronal values. SUMER can also be
  operated in a manner such that it makes images or spectroheliograms
  of different sizes in selected spectral lines. A detailed line profile
  with spectral resolution elements between 22 and 45 mÅ is produced for
  each line at each spatial location along the slit. From the line width,
  intensity and wavelength position we are able to deduce temperature,
  density, and velocity of the emitting atoms and ions for each emission
  line and spatial element in the spectroheliogram. Because of the high
  spectral resolution and low noise of SUMER, we have been able to detect
  faint lines not previously observed and, in addition, to determine
  their spectral profiles. SUMER has already recorded over 2000 extreme
  ultraviolet emission lines and many identifications have been made on
  the disk and in the corona.

---------------------------------------------------------
Title: High resolution solar ultraviolet measurements
Authors: Lemaire, P.; Wilhelm, K.; Schühle, U.; Curdt, W.; Poland,
   A. I.; Jordan, S. D.; Thomas, R. J.; Hassler, D. M.; Vial, J. -C.
1997AdSpR..20.2249L    Altcode:
  The increase of our understanding of the processes acting in the solar
  corona and maintaining it is strongly dependent on the quality of the
  data that are obtained to check theories. The fine structure of the
  solar atmosphere seen from the photosphere and extending to the hottest
  parts of the corona requires data with high resolution in all parameter
  space (angular, spectral and temporal). To constrain the hypotheses that
  are proposed to describe the solar corona, it is necessary to establish
  an accurate energy budget taking into account the processes which are
  acting from the chromosphere to the corona. Some requirements can be
  established and compared with the data collected so far (or about to
  be collected) with the present SUMER (Solar Utraviolet Measurements
  of Emitted Radiations) instrumentation.

---------------------------------------------------------
Title: First Results of the SUMER Telescope and Spectrometer on SOHO -
    II. Imagery and Data Management
Authors: Lemaire, P.; Wilhelm, K.; Curdt, W.; SchÜle, U.; Marsch,
   E.; Poland, A. I.; Jordan, S. D.; Thomas, R. J.; Hassler, D. M.; Vial,
   J. C.; KÜhne, M.; Huber, M. C. E.; Siegmund, O. H. W.; Gabriel, A.;
   Timothy, J. G.; Grewing, M.
1997SoPh..170..105L    Altcode:
  SUMER - Solar Ultraviolet Measurements of Emitted Radiation - is not
  only an extreme ultraviolet (EUV) spectrometer capable of obtaining
  detailed spectra in the range from 500 to 1610 Å, but, using the
  telescope mechanisms, it also provides monochromatic images over
  the full solar disk and beyond, into the corona, with high spatial
  resolution. We report on some aspects of the observation programmes
  that have already led us to a new view of many aspects of the Sun,
  including quiet Sun, chromospheric and transition region network,
  coronal hole, polar plume, prominence and active region studies. After
  an introduction, where we compare the SUMER imaging capabilities to
  previous experiments in our wavelength range, we describe the results
  of tests performed in order to characterize and optimize the telescope
  under operational conditions. We find the spatial resolution to be
  1.2 arc sec across the slit and 2 arc sec (2 detector pixels) along
  the slit. Resolution and sensitivity are adequate to provide details
  on the structure, physical properties, and evolution of several solar
  features which we then present. Finally some information is given on
  the data availability and the data management system.

---------------------------------------------------------
Title: High-Resolution Observations of the Extreme Ultraviolet Sun
Authors: Harrison, R. A.; Fludra, A.; Pike, C. D.; Payne, J.;
   Thompson, W. T.; Poland, A. I.; Breeveld, E. R.; Breeveld, A. A.;
   Culhane, J. L.; Kjeldseth-Moe, O.; Huber, M. C. E.; Aschenbach, B.
1997SoPh..170..123H    Altcode:
  This paper presents first results of the Coronal Diagnostic Spectrometer
  (CDS) recently launched aboard the Solar and Heliospheric Observatory
  (SOHO). CDS is a twin spectrometer, operating in the extreme ultraviolet
  range 151-785 Å. Thus, it can detect emission lines from trace
  elements in the corona and transition region which will be used to
  provide diagnostic information on the solar atmosphere. In this paper,
  we present early spectra and images, to illustrate the performance of
  the instrument and to pave the way for future studies.

---------------------------------------------------------
Title: Coordinated Observations of Prominences with SUMER/CDS and
    Ground Observatories
Authors: Wiik, J. E.; Schmieder, B.; Kucera, T.; Poland, A.
1997ASPC..118..278W    Altcode: 1997fasp.conf..278W
  An international campaign for the observation of prominences
  and filaments was successfully accomplished between June 3 and
  9 1996. Several ground observatories took part in the campaign
  which included the space observatories SOHO and Yohkoh. The main
  objective of this campaign was to study the dynamics of prominences
  and the prominence-corona interface, the formation of filaments and
  the fine structures at different temperatures. We will reported on
  two Joint Observing Programmes of SUMER and CDS aboard SOHO (JOP 12
  and JOP 17), which have been achieved. Finally we will present as an
  exemple a prominence observed on May 1, 1996 during the tests of the
  programme JOP 12. This prominence was associated with a CME (observed
  with LASCO). Very active parts with Dopplershifs up to +/- 36kms(-1)
  were measured in the SUMER spectra of the prominence, indicating the
  presence of twisted ropes during the eruption. Mean electron densities
  have spatial and temporal dispersion of one order of magnitude (10(9)
  - 10(10) cm(-3) ).

---------------------------------------------------------
Title: The structure of the solar corona as observed by the Solar
    Extreme Ultraviolet Rocket Telescope and Spectrograph
Authors: Davila, Joseph M.; Thomas, Roger J.; Brosius, Jeffrey;
   Poland, Arthur
1997AdSpR..20.2293D    Altcode:
  Data from the Solar Extreme-ultraviolet Rocket Telescope and
  Spectrograph (SERTS) have been used to address a number of important
  scientific problems. The primary strength of the SERTS data is the
  fact that this spectral range is rich with emission lines. Over 270
  lines are seen in the SERTS active Sun spectrum, from 57 different
  ions. For example, multiple (&gt;= 4) lines are observed for all
  ionization states of iron from Fe IX to Fe XVII. Temperatures and
  densities have been derived for a number of active and quiet Sun
  regions, the coronal magnetic field strength has been estimated for
  both a plage region and an active region.

---------------------------------------------------------
Title: "Prominences, filaments and chromospheric activity" June 1996
    campaign with SOHO, YOHKOH and Wrocław.
Authors: Wiik, J. E.; Rudawy, P.; Schmieder, B.; Kucera, T.; Rompolt,
   B.; Poland, A.
1997joso.proc...93W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The sun as never viewed before
Authors: Poland, A. I.
1997EOSTr..78..133P    Altcode:
  With the launch of the Solar and Heliospheric Observatory (SOHO), on
  December 2, 1995, solar physics entered a new era of “viewing”
  the Sun and heliosphere without interferences from the Earth's
  atmosphere. SOHO is a mission of international cooperation between the
  European Space Agency (ESA) and NASA. The most exciting new discoveries
  from SOHO include the unexpectedly high magnetic activity observed
  during the very minimum of the solar cycle and the “observation”
  of the interior structure of the Sun (helioseismology). The coronal
  instruments are showing that coronal mass ejections (CMEs) leave the
  Sun more frequently than expected, at the rate of approximately one
  per day. The helioseismology experiments, with their extremely low
  noise due to the absence of the Earth's atmospheric interference,
  are showing that convective cells under the solar surface are shaped
  like pancakes, not spheres as was previously assumed.

---------------------------------------------------------
Title: Extreme ultraviolet observations of the solar corona: first
    results from the coronal diagnostic spectrometer on SOHO
Authors: Harrison, R. A.; Fludra, A.; Sawyer, E. C.; Culhane, J. L.;
   Norman, K.; Poland, A. I.; Thompson, W. T.; Kjeldseth-Moe, O.;
   Aschenbach, B.; Huber, M. C. E.; Gabriel, A. H.; Mason, H. E.
1997AdSpR..20.2239H    Altcode:
  We present first results from the Coronal Diagnostic Spectrometer (CDS)
  aboard the ESA/NASA Solar and Heliospheric Observatory (SOHO). CDS is
  a double spectrometer operating in the 151-785 A˚ range. This region
  of the solar spectrum is rich in emission lines from trace elements
  in the solar atmosphere, which can be used to derive diagnostic
  information on coronal and transition region plasma. Early spectra are
  presented and well identified lines are listed. In addition, examples
  of images in selected wavelength ranges are shown, for a prominence,
  a loop system and a bright point, demonstrating well the power of such
  extreme ultraviolet observations.

---------------------------------------------------------
Title: The first results from SOHO.
Authors: Domingo, V.; Fleck, B.; Poland, A.
1996ESABu..87....7D    Altcode:
  SOHO, launched by an Atlas II-AS from Cape Canaveral on 2 December 1995,
  was inserted into its halo orbit around the L1 Lagrangian point. Typical
  examples of the unique results being obtained with SOHO's instruments
  are presented.

---------------------------------------------------------
Title: SOHO-Solar and Heliospheric Observatory
Authors: Poland, A. I.
1996AAS...188.4901P    Altcode: 1996BAAS...28..896P
  With the successful launch of SOHO on Dec. 2, 1995 we are beginning a
  new era of solar and heliospheric observations. SOHO is a space mission
  of international co-operation between the European Space Agency (ESA)
  and NASA designed to study the sun and heliosphere from the vicinity
  of the sun-earth L1 point. In this talk I will give an overview of
  the first results and planned observations in the three areas of the
  sun/heliosphere system: the solar interior as studied through the
  techniques of helioseismology; the solar atmosphere and studies of the
  heating and acceleration of the solar wind; and in-situ measurements
  of the solar wind as observed at L1. I will also discuss the framework
  in which SOHO is operated and how other scientist, not already involved
  in the SOHO mission, can get involved with the program.

---------------------------------------------------------
Title: A Solar EUV Spectral Atlas Observed with SUMER
Authors: Brekke, P.; Wilhelm, K.; Lemaire, P.; Curdt, W.; Schuhle,
   U.; Poland, A.; Kucera, T.; Hassler, D. M.; Siegmund, O. H. W.
1996AAS...188.3713B    Altcode: 1996BAAS...28..879B
  We present the first solar EUV spectral atlas in the wavelength range
  500 -- 1600 { Angstroms}. The spectra were recorded with the Solar
  Ultraviolet Measurements of Emitted Radiation (SUMER) which is part
  of the ESA/NASA Solar and Heliospheric Observatory (SOHO). The solar
  spectrum below 1200 { Angstroms} is not very well known. Thus, the
  present spectral atlas, and SUMER observations in general, represents
  a new important diagnostic tool to study essential physical parameters
  of the solar atmosphere. It includes emission from atoms and ions in
  the temperature range 10(4) to 2 x 10(6) K. Thus, emission lines and
  continua emitted from the lower chromosphere to the lower corona
  can be studied. The atlas is also useful as a planning tool for
  SUMER studies to determine useful dwell times, possible blends, and
  to select proper data extraction windows. The angular resolution of
  SUMER is close to 1 arcsec, but the atlas presented here represents an
  average along part of the 1-arcsec wide slit, typically 30 arcsec. The
  spectral resolving power of the instrument is lambda /Delta lambda =
  17770-38300. For more details about the SUMER instrument we refer to
  Wilhelm et al. (Solar Physics, 162, 189, 1995). The spectral data in
  this atlas were obtained with the spectrometer slit positioned at the
  center of the solar disk with a dwell time of 300 s to bring up weak
  lines and continua. The full spectral range was put together from
  a number of exposures each covering approximately 20 { Angstroms}
  in 1st order on the coated, and therefore most sensitive, part (KrB)
  of the detector. 1st and 2nd order spectra are superimposed. The
  spectral atlas is available in a computer readable format together
  with a IDL program to read and display the data using a widget
  interface. The atlas and the programs can be obtained via the World
  Wide Web (http://hydra.mpae.gwdg.de/mpae_projects/SUMER/sumer.html)
  or by contacting one of the authors.

---------------------------------------------------------
Title: Preface
Authors: Fleck, B.; Domingo, V.; Poland, A.
1995SoPh..162D...9F    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The Coronal Diagnostic Spectrometer for the Solar and
    Heliospheric Observatory
Authors: Harrison, R. A.; Sawyer, E. C.; Carter, M. K.; Cruise,
   A. M.; Cutler, R. M.; Fludra, A.; Hayes, R. W.; Kent, B. J.; Lang,
   J.; Parker, D. J.; Payne, J.; Pike, C. D.; Peskett, S. C.; Richards,
   A. G.; Gulhane, J. L.; Norman, K.; Breeveld, A. A.; Breeveld, E. R.; Al
   Janabi, K. F.; Mccalden, A. J.; Parkinson, J. H.; Self, D. G.; Thomas,
   P. D.; Poland, A. I.; Thomas, R. J.; Thompson, W. T.; Kjeldseth-Moe,
   O.; Brekke, P.; Karud, J.; Maltby, P.; Aschenbach, B.; Bräuninger,
   H.; Kühne, M.; Hollandt, J.; Siegmund, O. H. W.; Huber, M. C. E.;
   Gabriel, A. H.; Mason, H. E.; Bromage, B. J. I.
1995SoPh..162..233H    Altcode:
  The Coronal Diagnostic Spectrometer is designed to probe the solar
  atmosphere through the detection of spectral emission lines in the
  extreme ultraviolet wavelength range 150 - 800 å. By observing
  the intensities of selected lines and line profiles, we may derive
  temperature, density, flow and abundance information for the plasmas
  in the solar atmosphere. Spatial and temporal resolutions of down to
  a few arcseconds and seconds, respectively, allow such studies to be
  made within the fine-scale structure of the solar corona. Futhermore,
  coverage of large wavelength bands provides the capability for
  simultaneously observing the properties of plasmas across the wide
  temperature ranges of the solar atmosphere.

---------------------------------------------------------
Title: SUMER - Solar Ultraviolet Measurements of Emitted Radiation
Authors: Wilhelm, K.; Curdt, W.; Marsch, E.; Schühle, U.; Lemaire,
   P.; Gabriel, A.; Vial, J. -C.; Grewing, M.; Huber, M. C. E.; Jordan,
   S. D.; Poland, A. I.; Thomas, R. J.; Kühne, M.; Timothy, J. G.;
   Hassler, D. M.; Siegmund, O. H. W.
1995SoPh..162..189W    Altcode:
  The instrument SUMER - Solar Ultraviolet Measurements of Emitted
  Radiation is designed to investigate structures and associated dynamical
  processes occurring in the solar atmosphere, from the chromosphere
  through the transition region to the inner corona, over a temperature
  range from 10<SUP>4</SUP> to 2 × 10<SUP>6</SUP>K and above. These
  observations will permit detailed spectroscopic diagnostics of plasma
  densities and temperatures in many solar features, and will support
  penetrating studies of underlying physical processes, including plasma
  flows, turbulence and wave motions, diffusion transport processes,
  events associated with solar magnetic activity, atmospheric heating,
  and solar wind acceleration in the inner corona. Specifically, SUMER
  will measure profiles and intensities of EUV lines; determine Doppler
  shifts and line broadenings with high accuracy; provide stigmatic
  images of the Sun in the EUV with high spatial, spectral, and temporal
  resolution; and obtain monochromatic maps of the full Sun and the inner
  corona or selected areas thereof. SUMER will be flown on the Solar
  and Heliospheric Observatory (SOHO), scheduled for launch in November,
  1995. This paper has been written to familiarize solar physicists with
  SUMER and to demonstrate some command procedures for achieving certain
  scientific observations.

---------------------------------------------------------
Title: The SOHO mission.
Authors: Fleck, B.; Domingo, V.; Poland, A. I.
1995SoPh..162.....F    Altcode:
  SOHO, the Solar and Heliospheric Observatory, is a project of
  international cooperation between ESA and NASA to study the Sun, from
  its deep core to the outer corona. This special issue is dedicated to
  the SOHO payload and to its operation.

---------------------------------------------------------
Title: The SOHO Mission: an Overview
Authors: Domingo, V.; Fleck, B.; Poland, A. I.
1995SoPh..162....1D    Altcode:
  The Solar and Heliospheric Observatory (SOHO) is a space mission
  that forms part of the Solar-Terrestrial Science Program (STSP),
  developed in a collaborative effort by the European Space Agency (ESA)
  and the National Aeronautics and Space Administration (NASA). The
  STSP constitutes the first "cornerstone" of ESA's long-term
  programme known as "Space Science — Horizon 2000". The principal
  scientific objectives of the SOHO mission are a) to reach a better
  understanding of the structure and dynamics of the solar interior
  using techniques of helioseismology, and b) to gain better insight
  into the physical processes that form and heat the Sun's corona,
  maintain it and give rise to its acceleration into the solar wind. To
  achieve these goals, SOHO carries a payload consisting of 12 sets of
  complementary instruments. SOHO is a three-axis stabilized spacecraft
  with a total mass of 1850 kg; 1150 W of power will be provided by
  the solar panels. The payload weighs about 640 kg and will consume
  450 W in orbit. SOHO will be launched by an ATLAS II-AS and will
  be placed in a halo orbit around the Sun-Earth L1 Lagrangian point
  where it will be continuously pointing to Sun centre with an accuracy
  of 10 arcsec. Pointing stability will be better than 1 arcsec over
  15 min intervals. The SOHO payload produces a continuous science
  data stream of 40 kbits/s which will be increased by 160 kbits/s
  whenever the solar oscillations imaging instrument is operated in its
  highrate mode. Telemetry will be received by NASA's Deep Space Network
  (DSN). Planning, coordination and operation of the spacecraft and the
  scientific payload will be conducted from the Experiment Operations
  Facility (EOF) at NASA's Goddard Space Flight Center (GSFC).

---------------------------------------------------------
Title: Some design and performance features of SUMER: solar
    ultraviolet measurements of emitted radiation
Authors: Wilhelm, Klaus; Curdt, W.; Marsh, E.; Schuehle, Udo H.;
   Lemaire, Philippe; Gabriel, Alan H.; Vial, J. -C.; Grewing, Michael;
   Huber, Martin C.; Jordan, S. D.; Poland, Arthur I.; Thomas, Roger J.;
   Kuehne, Mikhael; Timothy, J. Gethyn; Hassler, Donald M.; Siegmund,
   Oswald H.
1995SPIE.2517....2W    Altcode:
  The instrument SUMER (solar ultraviolet measurements of emitted
  radiation) is designed to investigate structures and associated
  dynamical processes occurring in the solar atmosphere from the
  chromosphere through the transition region to the inner corona, over a
  temperature range from 10<SUP>4</SUP> to 2 multiplied by 10<SUP>6</SUP>
  K and above. The observations will be performed, on board SOHO (solar
  and heliospheric observatory) scheduled for launch in November 1995,
  by a scanning, normal-incidence telescope/spectrometer system in
  the wavelength range from 500 to 1610 angstrom. Spatial resolution
  requirements compatible with the pointing stability of SOHO are less
  than 1000 km corresponding to about 1-arcsec angular resolution. Doppler
  observations of EUV line shifts and broadenings should permit solar
  plasma velocity measurements down to 1 km s<SUP>-1</SUP>. We report
  here on some specific features of this instrument related to its
  pointing as well as its spatial and spectral resolution capabilities.

---------------------------------------------------------
Title: Coronal Diagnostic Spectrometer: an extreme-ultraviolet
    spectrometer for the Solar and Heliospheric Observatory
Authors: Kent, Barry J.; Harrison, Richard A.; Sawyer, Eric C.;
   Hayes, R. W.; Richards, Anthony G.; Culhane, John L.; Norman, K.;
   Breeveld, A. A.; Thomas, P. D.; Poland, Arthur I.; Thomas, Roger J.;
   Thompson, William T.; Aschenbach, Bernd R.; Braeuninger, Heinrich
   W.; Kjeldseth-Moe, O.; Kuehne, Mikhael; Hollandt, J.; Paustian, W.;
   Bromage, B. J.
1995SPIE.2517...12K    Altcode:
  The coronal diagnostic spectrometer is designed to probe the solar
  atmosphere through the detection of spectral emission lines in the
  extreme ultraviolet wavelength range 15.0 - 80.0 nm. By observing
  the intensities of selected lines and line profiles, it is possible
  to derive temperature, density, flow, and abundance information for
  the plasmas in the solar atmosphere. Spatial resolution down to
  a few arcseconds and temporal resolution of seconds, allows such
  studies to be made within the fine-scale structure of the solar
  corona. Furthermore, coverage of a large wavelength band provides
  the capability for simultaneously observing the properties of plasma
  across the wide temperature ranges of the solar atmosphere. The
  CDS design makes use of a Wolter-Schwarzschild II telescope which
  simultaneously illuminates two spectrometer systems, one operating
  in normal incidence the other in grazing incidence. In this paper we
  describe the salient features of the design of the CDS instrument and
  discuss the performance characteristics of CDS as established through
  pre-delivery test and calibration activities.

---------------------------------------------------------
Title: SOHO: The Solar and Heliospheric Observatory
Authors: Domingo, V.; Fleck, B.; Poland, A. I.
1995SSRv...72...81D    Altcode:
  The Solar and Heliospheric Observatory (SOHO), together with the Cluster
  mission, constitutes ESA's Solar Terrestrial Science Programme (STSP),
  the first “Cornerstone” of the Agency's long-term programme “Space
  Science — Horizon 2000”. STSP, which is being developed in a strong
  collaborative effort with NASA, will allow comprehensive studies
  to be made of the both the Sun's interior and its outer atmosphere,
  the acceleration and propagation of the solar wind and its interaction
  with the Earth. This paper gives a brief overview of one part of STSP,
  the SOHO mission.

---------------------------------------------------------
Title: The SOHO mission
Authors: Fleck, B.; Domingo, V.; Poland, A.
1995somi.book.....F    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: SOHO: The Solar and Heliospheric Observatory
Authors: Domingo, V.; Fleck, B.; Poland, A. I.
1995hlh..conf...81D    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The SOHO mission Poland.
Authors: Fleck, B.; Domingo, V.; Poland, Arthur I.
1995sohp.book.....F    Altcode: 1995QB521.S5828....
  No abstract at ADS

---------------------------------------------------------
Title: Coronal fine structure as seen in the Skylab white light
    coronagraph
Authors: Poland, A. I.
1994ESASP.373..227P    Altcode: 1994soho....3..227P
  No abstract at ADS

---------------------------------------------------------
Title: The scientific payload of the space-based Solar and
    Heliospheric Observatory (SOHO)
Authors: Domingo, V.; Fleck, B.; Poland, A. I.
1994SSRv...70....7D    Altcode:
  The space-based Solar and Heliospheric Observatory (SOHO) is a joint
  venture of ESA and NASA within the frame of the Solar Terrestrial
  Science Programme (STSP), the first “Cornerstone” of ESA's long-term
  programme “Space Science — Horizon 2000”. The principal scientific
  objectives of the SOHO mission are: a) a better understanding of
  the structure and dynamics of the solar interior using techniques of
  helioseismology, and b) a better insight into the physical processes
  that form and heat the Sun's corona, maintain it and give rise to
  its acceleration into the solar wind. To achieve these goals, SOHO
  carries a payload consisting of 12 sets of complementary instruments
  which are briefly described here.

---------------------------------------------------------
Title: SOHO operations and ground system
Authors: Poland, A. I.; Domingo, V.; Fleck, B.
1994SSRv...70...13P    Altcode:
  SOHO is a joint ESA/NASA mission to study the sun from its interior to,
  and including, the solar wind in interplanetary space. It is currently
  scheduled for launch in 1995. After launch SOHO with be operated from
  the Experiment Operations Facility (EOF) at Goddard Space Flight Center
  (GSFC). The EOF will consist of facilities for instrument commanding,
  data reception, data reduction and data analysis. In this paper the
  operations concepts including instrument ground commanding from the EOF
  and communications capabilities between the EOF and ground observatories
  and the public networks in general will be described.

---------------------------------------------------------
Title: Delay-line detectors for the UVCS and SUMER instruments on
    the SOHO Satellite
Authors: Siegmund, Oswald H.; Stock, Joseph M.; Marsh, Daniel R.;
   Gummin, Mark A.; Raffanti, Richard; Hull, Jeffrey; Gaines, Geoffrey
   A.; Welsh, Barry Y.; Donakowski, B.; Jelinsky, Patrick N.; Sasseen,
   Timothy; Tom, James L.; Higgins, B.; Magoncelli, T.; Hamilton, Jon W.;
   Battel, Steven J.; Poland, Arthur I.; Jhabvala, Murzy D.; Sizemore,
   K.; Shannon, J.
1994SPIE.2280...89S    Altcode:
  Microchannel plate based detectors with cross delay line image readout
  have been rapidly implemented for the SUMER and UVCS instruments
  aboard the Solar Orbiting Heliospheric Observatory (SOHO) mission to
  be launched in July 1995. In October 1993 a fast track program to
  build and characterize detectors and detector control electronics
  was initiated. We present the detector system design for the SOHO
  UVCS and SUMER detector programs, and results from the detector test
  program. Two deliverable detectors have been built at this point, a
  demonstration model for UVCS, and the flight Ly (alpha) detector for
  UVCS, both of which are to be delivered in the next few weeks. Test
  results have also been obtained with one other demonstration detector
  system. The detector format is 26mm x 9mm, with 1024 x 360 digitized
  pixels,using a low resistance Z stack of microchannel plates (MCP's) and
  a multilayer cross delay line anode (XDL). This configuration provides
  gains of approximately equals 2 X 10(superscript 7) with good pulse
  height distributions (&lt;50% FWHM) under uniform flood illumination,
  and background levels typical for this configuration (approximately
  equals 0.6 event cm(superscript -2) sec(superscript -1)). Local counting
  rates up to approximately equals 400 event/pixel/sec have been achieved
  with no degradation of the MCP gain. The detector and event encoding
  electronics achieves approximately equals 25 micrometers FWHM with
  good linearity (+/- approximately equals 1 pixel) and is stable to high
  global counting rates (&gt;4 X 10(superscript 5) events sec(superscript
  -1)). Flat field images are dominated by MCP fixed pattern noise and
  are stable, but the MCP multifiber modulation usually expected is
  uncharacteristically absent. The detector and electronics have also
  successfully passed both thermal vacuum and vibration tests.

---------------------------------------------------------
Title: 'SUMER' - Solar Ultraviolet Measurements of Emitted Radiation
Authors: Wilhelm, K.; Curdt, W.; Gabriel, A. H.; Grewing, M.; Huber,
   M. C. E.; Jordan, S. D.; Kuhne, M.; Lemaire, P.; Marsch, E.; Poland,
   A. I.; Schuhle, U.; Thomas, R. J.; Timothy, J. G.; Vial, J. -C.
1994scs..conf..619W    Altcode: 1994IAUCo.144..619W
  SUMER is designed for the investigations of plasma flow characteristics,
  turbulence and wave motions, plasma densities and temperatures,
  structures and events associated with solar magnetic activity in the
  chromosphere, the transition zone and the corona. The spatial and
  spectral resolution capabilities of the instrument are considered in
  some detail, and a new detector concept is introduced.

---------------------------------------------------------
Title: SOHO Science Opportunities
Authors: Fleck, B.; Domingo, V.; Poland, A. I.
1994scs..conf..609F    Altcode: 1994IAUCo.144..609F
  The principal scientific objectives of the SOHO mission are: a)
  a better understanding of the structure and dynamics of the solar
  interior using techniques of helioseismology, and b) a better insight
  into the physical processes that form and heat the Sun's corona,
  maintain it and give rise to its acceleration into the solar wind. To
  achieve these goals, SOHO carries a payload consisting of 12 sets of
  complementary instruments which are briefly described here.

---------------------------------------------------------
Title: SOHO Operations
Authors: Fleck, B.; Domingo, V.; Poland, A. I.
1994scs..conf..614F    Altcode: 1994IAUCo.144..614F
  SOHO, the Solar and Heliospheric Observatory, is currently scheduled
  for launch in 1995. After launch SOHO will be operated from the
  Experiment Operations Faciliy (EOF) at Goddard Space Flight Center
  (GSFC). The EOF will consist of facilities for instrument commanding,
  data reception, data reduction and data analysis. This paper briefly
  describes the operations concepts.

---------------------------------------------------------
Title: SOHO: science objectives and capabilities
Authors: Fleck, B.; Domingo, V.; Poland, A. I.
1994ASIC..433..517F    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: SUMER - Solar Ultraviolet Measurements of Emitted Radiation
Authors: Wilhelm, K.; Curdt, W.; Marsch, E.; Schuehle, U.; Gabriel,
   A. H.; Lemaire, P.; Vial, J. -C.; Grewing, M.; Huber, M. C. E.;
   Jordan, S. D.; Poland, A. I.; Thomas, R. J.; Kuehne, M.; Timothy, J. G.
1993BAAS...25.1192W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Invited Talk: (SOHO Coronal Observations)
Authors: Poland, A. I.
1993BAAS...25.1195P    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: SUMER: temperatures, densities, and velocities in the outer
    solar atmosphere.
Authors: Lemaire, P.; Wilhelm, K.; Axford, W. I.; Curdt, W.; Gabriel,
   A. H.; Grewing, M.; Huber, M. C. E.; Jordan, S. D.; Kuehne, M.;
   Marsch, E.; Poland, A. I.; Richter, A. K.; Thomas, R. J.; Timothy,
   J. G.; Vial, J. C.
1992ESASP.348...13L    Altcode: 1992cscl.work...13L
  The SUMER instrumentation, that will be mounted on the SOHO spacecraft,
  is in development under MPAE leadership. It has some capability
  to improve the solar angular resolution and the spectral resolution
  already obtained in the far UV to the extreme UV, corresponding to the
  temperature range between 10<SUP>4</SUP> and a few 10<SUP>6</SUP>K. The
  authors give some insights into the SUMER spectrometer that is developed
  to study the dynamics and to infer temperatures and densities of the
  low corona and the chromosphere-corona transition zone in using the
  50 - 160 nm wavelength range. First, they recall the SUMER scientific
  goals and the technics used. Then, after a brief description of the
  instrumentation the expected performances are described. The way the
  observations can be conducted is emphasized and it is shown how SUMER
  is operated in coordination with other SOHO instrumentations and in
  cooperation with ground-based observations.

---------------------------------------------------------
Title: Measurements of an intensified CCD detector for the solar
    and heliospheric observatory
Authors: Thompson, William T.; Poland, Arthur I.; Siegmund, Oswald H.;
   Swartz, Marvin; Leviton, Douglas B.; Payne, Leslie J.
1992SPIE.1743..464T    Altcode:
  An engineering model intensified CCD detector for the SOHO Coronal
  Diagnostics Spectrometer has been built and tested at the NASA Goddard
  Space Flight Center. A windowless MCP intensifier tube converts EUV
  radiation (30 - 65 nm) into visible light, which is focused via a lens
  system onto a Tektronix 1024 X 1024 CCD. Tests have been made of this
  engineering model to determine the following characteristics: quantum
  efficiency, resolution, throughput, linearity, statistical variation,
  readout noise, scattering, and flat-field response. In almost all
  respects, the detector performed as expected. This detector has been
  delivered, and work is underway on the flight detector.

---------------------------------------------------------
Title: "SUMER" - Solar Ultraviolet Measurements of Emitted Radiation.
Authors: Wilhelm, K.; Axford, W. I.; Curdt, W.; Gabriel, A. H.;
   Grewing, M.; Huber, M. C. E.; Jordan, S. D.; Kühne, M.; Lemaire, P.;
   Marsch, E.; Poland, A. I.; Richter, A. K.; Thomas, R. J.; Timothy,
   J. G.; Vial, J. C.
1992eocm.rept..225W    Altcode:
  The experiment Solar Ultraviolet Measurements of Emitted Radiation
  (SUMER) is designed for the investigations of plasma flow
  characteristics, turbulence and wave motions, plasma densities
  and temperatures, structures and events associated with solar
  magnetic activity in the chromosphere, the transition zone and the
  corona. Specifically, SUMER will measure profiles and intensities
  of extreme ultraviolet (EUV) lines emitted in the solar atmosphere
  ranging from the upper chromosphere to the lower corona; determine line
  broadenings, spectral positions and Doppler shifts with high accuracy;
  provide stigmatic images of selected areas of the Sun in the EUV with
  high spatial, temporal and spectral resolution and obtain full images of
  the Sun and the inner corona in selectable EUV lines, corresponding to a
  temperature range from 10<SUP>4</SUP> to more than 1.8×10<SUP>6</SUP>K.

---------------------------------------------------------
Title: SOHO - An Observatory to Study the Solar Interior and the
    Solar Atmosphere
Authors: Poland, A. I.
1992AAS...180.3306P    Altcode: 1992BAAS...24..781P
  No abstract at ADS

---------------------------------------------------------
Title: Opacity Effects on the Radiative Losses of Coronal Loops
Authors: Kuin, N. P. M.; Poland, A. I.
1991ApJ...370..763K    Altcode:
  This paper presents calculations of radiative losses, which include the
  effects of geometry and optical depth, that can be used to improve the
  energy losses in many flux-tube calculations for loops with constant
  and variable cross sections. The results include the non-LTE ionization
  state of hydrogen and helium, thus allowing the determination of the
  ionization energy in the gas and the relative importance of collisional
  and radiative processes. These calculations show that optical depth
  effects are important under solar conditions in the temperature range
  of 8000-40,000 K.

---------------------------------------------------------
Title: The SOHO Space Satellite: UV instrumentation.
Authors: Poland, Arthur I.; Domingo, Vicente
1991SPIE.1343..310P    Altcode:
  The solar and heliospheric observatory, SOHO will be placed into a halo
  orbit around the L1 sun-earth Lagrangian point in 1995. The authors
  describe the ultra-violet and EUV instruments designed to study
  the solar atmosphere from the chromosphere through the corona. The
  instruments and their basic characteristics are: 1) SUMER - a normal
  incidence telescope with a normal incidence spherical concave grating
  for stigmatic imaging to measure line profiles and images in the
  wavelength range from 500 Å to 1600 Å with a 1.5″resolution; 2) CDS
  - a grazing incidence telescope with one grazing incidence astigmatic
  spectrograph and one normal incidence toroidal grating spectrograph
  to measure line ratios and images in the range from 170 Å to 800
  Å with a 2″resolution; 3) EIT - a normal incidence multilayered
  telescope to produce narrow band pass images in the spectral lines at
  171 Å, 195 Å, 284 Å, and 304 Å with a 3″resolution; 4) UVCS - a
  normal incidence coronagraph with a normal incidence toroidal grating
  spectrograph to measure line profiles and images of several EUV lines
  from ≡500 Å to ≡1200 Å with a several arcsecond resolution;
  and 5) SWAN - a lens with hydrogen absorption cell and interference
  filter to measure Ly-α profiles in the far corona and heliosphere.

---------------------------------------------------------
Title: An intensified CCD detector using the phosphor TPB.
Authors: Thompson, William T.; Swartz, Marvin; Poland, Arthur I.
1990SPIE.1344..415T    Altcode: 1990exrg.conf..415T
  The Research Amplifying Imaging Detector (RAID) consists of a
  microchannel plate image intensifier with a thin coating (3500 - 10,000
  Å) of the phosphor tetraphenyl-butadiene (TPB) on the entrance window
  to convert EUV radiation to visible, and coupled via a lens to a CCD
  detector. This design allows great flexibility in selecting the pixel
  size and field of view, with a simple mechanical design. Tests have
  been made at visible and EUV (304 Å) wavelengths of the following
  performance aspects: EUV spectral sensitivity, spatial resolution
  both of components and of the system as a whole, noise, linearity,
  and dynamic range.

---------------------------------------------------------
Title: SOHO - an Observatory to Study the Solar Interior and the
    Solar Atmosphere
Authors: Poland, A. I.; Domingo, V.
1990ASSL..166..277P    Altcode: 1990oeob.coll..277P; 1990IAUCo.123..277P
  The Solar and Heliospheric Observatory (SOHO) is described. The two
  main objectives of SOHO are to improve understanding of solar coronal
  phenomena and to study solar structure and interior dynamics from
  its core to the photosphere. The primary goals of the coronal and
  solar wind studies are to understand the coronal heating mechanism
  and its expansion into the solar wind. These goals will be achieved
  both by remote sensing of the solar atmosphere with high resolution
  spectrometers and telescopes and by in situ measurement of the
  composition and energy of the resulting solar wind and the energetic
  particles that propagate through it. The structure and interior dynamics
  are to be studied by helioseismological methods and the measurement
  of solar irradiance variations. The SOHO spacecraft will be three-axis
  stabilized and located in a halo orbit around the L1 Lagrangian point
  (approximately 1 percent of the distance from the Earth to the Sun). It
  is currently scheduled for launch in July 1995.

---------------------------------------------------------
Title: Mass and Energy Flow in Prominences
Authors: Poland, Arthur I.
1990LNP...363..120P    Altcode: 1990doqp.coll..120P; 1990IAUCo.117..120P
  Mass and energy flow in quiescent prominences is considered based on the
  hypothesis that active region prominences have a different structure
  and thus different mass and energy flow characteristics. Several
  important physical parameters have been plotted using the computational
  model, representing the evolutionary process after the prominence
  formation. The temperature, velocity, conductive flux, and enthalpy
  flux are plotted against distance from the highest point in the loop
  to the coolest part of the prominence. It is shown that the maximum
  velocity is only about 5 km/s. The model calculations indicate that the
  transition region of prominences is dominated by complex processes. It
  is necessary to take into account mass flow at temperatures below
  200,000 K, and both mass flow and optical depth effects in hydrogen
  at temperatures below 30,000 K. Both of these effects lead to a less
  steep temperature gradient through the prominence corona interface
  than can be obtained from the conduction alone.

---------------------------------------------------------
Title: The Eruption of a Quiescent Prominence as Observed in
    Ultraviolet Lines
Authors: Fontenla, J. M.; Poland, A. I.
1989SoPh..123..143F    Altcode:
  We compare observations of an eruptive and a quiescent prominence
  in order to better understand the energetic processes in an eruptive
  prominence. Observations of an eruptive prominence were obtained in
  Hα, several UV emission lines (1215-1640 Å), and coronal white light
  at approximately 19:00 UT on September 20, 1980. The data we present
  shows the development of the eruption in the Hα and UV emission lines
  and is compared with the intensities from similar observations of a
  quiescent prominence. While the event is coincident with some coronal
  changes, above 1.2 and up to 1.5 solar radii, it does not result in
  a true coronal mass ejection event.

---------------------------------------------------------
Title: SUMER - Solar ultraviolet measurements of emitted radiation.
Authors: Curdt, W.; Wilhelm, K.; Axford, W. I.; Marsch, E.; Richter,
   A. K.; Gabriel, A. H.; Lemaire, P.; Vial, J. -C.; Grewing, M.; Huber,
   M. C. E.; Jordan, S. D.; Poland, A. I.; Thomas, R. J.; Timothy, J. G.
1989AGAb....2...14C    Altcode: 1989amt..conf...14C
  No abstract at ADS

---------------------------------------------------------
Title: Opacity Effects on the Radiative Losses of Coronal Loops
Authors: Kuin, N. P. M.; Poland, A. I.
1989BAAS...21Q.711K    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Impulsive phase transport.
Authors: Canfield, R. C.; Bely-Dubau, E.; Brown, J. C.; Dulk, G. A.;
   Emslie, A. G.; Enome, S.; Gabriel, A. H.; Kundu, M. R.; Melrose,
   D.; Neidig, D. F.; Ohki, K.; Petrosian, V.; Poland, A.; Rieger, E.;
   Tanaka, K.; Zirin, H.
1989epos.conf..225C    Altcode:
  The work of this group was concerned with how the energy released
  in a solar flare is transported through the solar atmosphere before
  escaping in the form of radiant and mechanical energy.

---------------------------------------------------------
Title: SOHO: an observatory to study the solar interior and the
    solar atmosphere
Authors: Domingo, V.; Poland, A. I.
1988sohi.rept....7D    Altcode:
  The Solar and Heliospheric Observatory (SOHO) is described. The two
  main objectives of SOHO are to improve understanding of solar coronal
  phenomena and to study solar structure and interior dynamics from
  its core to the photosphere. The primary goals of the coronal and
  solar wind studies are to understand the coronal heating mechanism
  and its expansion into the solar wind. These goals will be achieved
  both by remote sensing of the solar atmosphere with high resolution
  spectrometers and telescopes and by in situ measurement of the
  composition and energy of the resulting solar wind and the energetic
  particles that propagate through it. The structure and interior dynamics
  are to be studied by helioseismological methods and the measurement
  of solar irradiance variations. The SOHO spacecraft will be three-axis
  stabilized and located in a halo orbit around the L1 Lagrangian point
  (approximately 1 percent of the distance from the Earth to the Sun). It
  is currently scheduled for launch in July 1995.

---------------------------------------------------------
Title: SUMER: Solar Ultraviolet Measurements of Emitted Radiation
Authors: Wilhelm, K.; Axford, W. I.; Curdt, W.; Gabriel, A. H.;
   Grewing, M.; Huber, M. C. E.; Jordan, M. C. E.; Lemaire, P.; Marsch,
   E.; Poland, A. I.
1988sohi.rept...31W    Altcode:
  The SUMER (solar ultraviolet measurements of emitted radiation)
  experiment is described. It will study flows, turbulent motions, waves,
  temperatures and densities of the plasma in the upper atmosphere of
  the Sun. Structures and events associated with solar magnetic activity
  will be observed on various spatial and temporal scales. This will
  contribute to the understanding of coronal heating processes and the
  solar wind expansion. The instrument will take images of the Sun in EUV
  (extreme ultra violet) light with high resolution in space, wavelength
  and time. The spatial resolution and spectral resolving power of the
  instrument are described. Spectral shifts can be determined with
  subpixel accuracy. The wavelength range extends from 500 to 1600
  angstroms. The integration time can be as short as one second. Line
  profiles, shifts and broadenings are studied. Ratios of temperature
  and density sensitive EUV emission lines are established.

---------------------------------------------------------
Title: An Intensified CCD EUV Camera for the SOHO/CDS Experiment
Authors: Golub, L.; Kalata, K.; Poland, A. I.; Thomas, R. J.
1988BAAS...20..980G    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Hydrogen and Helium Excitation by Extreme Ultraviolet Radiation
    for the Production of White-Light Flares
Authors: Poland, A. I.; Milkey, R. W.; Thompson, W. T.
1988SoPh..115..277P    Altcode:
  White-light flares are defined as those flares that produce significant
  enhancement of emission in the visible light continuum. The source
  of energy for this emission has not yet been identified with several
  possibilities being suggested: heating of the lower chromosphere by some
  mechanical or magnetic means, or by soft X-ray or extreme ultraviolet
  radiation from coronal loops being absorbed in the lower chromosphere
  and re-emitted in the visible.

---------------------------------------------------------
Title: Some dynamical aspects of a quiescent filament
Authors: Schmieder, B.; Demoulin, P.; Poland, A.; Thompson, B.
1988A&A...197..281S    Altcode:
  A typical quiescent filament was observed on the disk in the Hα
  and C IV lines during a period of approximately one hour. Vertical
  velocities (&lt;2.5 km s<SUP>-1</SUP>) with a time scale of 5 min and
  a spatial scale of a few tens of seconds of arc were detected in Hα,
  and associated with microturbulence in both lines. The C IV observations
  correlated well with those in Hα, and showed no indication of material
  heating from Hα to C IV temperatures. Two mechanisms to explain these
  observations are proposed: mass motion along twisted magnetic field
  or instabilities triggering waves along the filament.

---------------------------------------------------------
Title: The SOHO project: helioseismology investigations
Authors: Domingo, V.; Poland, A.
1988AdSpR...8k.109D    Altcode: 1988AdSpR...8..109D
  The solar and heliospheric observatory, Soho, will be placed into a
  halo orbit around the L1 Sun-Earth Lagrangian point in 1995. It will
  carry a set of instruments to study the physical phenomena in the
  solar atmosphere that heat the solar corona, the mechanisms by which
  the solar corona expands into the solar wind, and investigate the
  structure of the solar interior by the study of solar oscillations,
  both in velocity and in intensity (Helioseismology). <P />In this paper
  we describe the mission and the investigations to be carried out with
  the helioseismology instruments in the payload. A solar oscillations
  imager will measure velocity oscillations of degree up to 4000, while
  two other instruments will measure very long series of low degree modes
  of oscillation, one of them in velocity and the other in irradiance. The
  data obtained will be used to study the radial stratification and the
  longitudinal variation of the physical characteristics of the Sun,
  as well as many dynamical phenomena of the upper layers of the solar
  atmosphere.

---------------------------------------------------------
Title: A model for the structure and formation of prominences.
Authors: Poland, A. I.; Mariska, J. T.
1988dssp.conf..133P    Altcode:
  The authors present a geometric model for the magnetic structure of
  a prominence inspired by recent high resolution images and magnetic
  field measurements of filaments and prominences. In this model the
  observed prominence structures are a mapping of locations in the
  magnetic field structure where material can condense without falling
  to the chromosphere. Vertical structures near the footpoints are a
  series of near potential fields.

---------------------------------------------------------
Title: Current Understanding and Issues on Electron Beam Injection
    in Space
Authors: Poland, A. I.; Domingo, V.
1988AdSpR...8k.101P    Altcode: 1988AdSpR...8Q.101P
  The Solar and Heliospheric Observatory (SOHO) satellite mission is
  planned to study the solar interior, to investigate the physical
  phenomena related to the formation of the solar corona and the solar
  wind, and to make in situ measurements of the solar wind. The SOHO
  instruments designed to study the solar atmosphere and the solar wind
  are described. The experiments include the study of solar UV radiation,
  a coronal diagnostic spectrometer, an extreme UV imaging telescope, a UV
  coronagraph spectrometer, a white light and spectrometric coronagraph,
  and a study of solar wind anisotropies.

---------------------------------------------------------
Title: Soho and Cluster - the scientific instruments.
Authors: Domingo, V.; Schmidt, R.; Poland, A. I.; Goldstein, M. L.
1988ESABu..56...24D    Altcode:
  The need to understand the complex processes that control the structure
  and dynamics of our daylight star and define the Earth's environment
  in space, has long been widely realised. Its continuing importance is
  reflected by the fact that twenty-three Principal Investigators and
  several hundred Co-Investigators from more than eighteen countries
  are now actively involved in the preparations for and execution of
  the Soho and Cluster missions.

---------------------------------------------------------
Title: A Model for the Structure and Formation of Prominences
Authors: Poland, A. I.; Mariska, J. T.
1987dssp.work..133P    Altcode: 1987ASSL..150..133P
  No abstract at ADS

---------------------------------------------------------
Title: Impulsive Phase Observations and Their Interpretation
Authors: Canfield, R. C.; Bely-Dumau, E.; Brown, J. C.; Dulk, G. A.;
   Emslie, A. G.; Enome, S.; Gabriel, A. H.; Kundu, M. R.; Melrose,
   D.; Neidig, D. F.; Ohki, K.; Petrosian, V.; Poland, A.; Rieger, E.;
   Tanaka, K.; Zirin, H.
1986epos.conf..3.4C    Altcode: 1986epos.confC...4C
  No abstract at ADS

---------------------------------------------------------
Title: Theoretical Studies of Transport Processes
Authors: Canfield, R. C.; Bely-Dumau, E.; Brown, J. C.; Dulk, G. A.;
   Emslie, A. G.; Enome, S.; Gabriel, A. H.; Kundu, M. R.; Melrose,
   D.; Neidig, D. F.; Ohki, K.; Petrosian, V.; Poland, A.; Rieger, E.;
   Tanaka, K.; Zirin, H.
1986epos.conf.3.34C    Altcode: 1986epos.confBC.34C
  No abstract at ADS

---------------------------------------------------------
Title: Coronal and Prominence Plasmas: proceedings of workshops held
    at Goddard Space Flight Center, April 9-11, 1985, April 8-10, 1986
Authors: Poland, Arthur I.
1986NASCP2442.....P    Altcode: 1986copp.nasa.....P
  No abstract at ADS

---------------------------------------------------------
Title: Numerical simulations of a siphon mechanism for quiescent
    prominence formation.
Authors: Poland, A. I.; Mariska, J. T.; Klimchuk, J. A.
1986NASCP2442...57P    Altcode: 1986copp.nasa...57P
  Quiescent prominences represent a significant challenge to our
  understanding of the flow of mass and energy in the outer layers of
  the solar atmosphere. A small number of quiescent prominences contain
  as much mass as the entire corona (Athay, 1976). The problem then is
  how to get that much material into the relatively small volume of
  a prominence and maintain it at a temperature of 10,000 K in close
  proximity to material at one million K. The thermal insulation to
  conduction provided by the magnetic field explains the disparate
  temperatures. The mass source problem is less well understood. One
  method for supplying mass to the prominence is to siphon it from the
  chromosphere. The siphon mechanism begins with a magnetic loop that
  evolves into a configuration with a gravitational well, such as that
  described by Kippenhahn and Schluter (1957). This could be formed, for
  example, by a twist in the magnetic field. A gravitational well could
  also be formed by a condensation induced sag in the field. This could
  further enhance the condensation process. Once this well has formed,
  or as it is forming, the material in the well area of the loop must
  cool and condense to the point where radiative losses exceed any
  heat input. Additional material must also flow into the well from
  the underlying chromosphere to supply the mass required to form the
  prominence. One example from a series of numerical simulations that were
  performed to study the formation of quiescent prominences is presented.

---------------------------------------------------------
Title: Constraints on filament models deduced from dynamical analysis.
Authors: Simon, G.; Schmieder, B.; Demoulin, P.; Malherbe, J. M.;
   Poland, A. I.
1986NASCP2442..177S    Altcode: 1986copp.nasa..177S
  The conclusions deduced from simultaneous observations with the
  Ultra-Violet Spectrometer and Polarimeter (UVSP) on the Solar Maximum
  Mission satellite, and the Multichannel Subtractive Double Pass (MSPD)
  spectrographs at Meudon and Pic du Midi observatories are presented. The
  observations were obtained in 1980 and 1984. All instruments have
  almost the same field of view and provide intensity and velocity maps
  at two temperatures. The resolution is approx. 0.5 to 1.5" for H alpha
  line and 3" for C IV. The high resolution and simultaneity of the two
  types of observations allows a more accurate description of the flows
  in prominences as functions of temperature and position. The results
  put some contraints on the models and show that dynamical aspects must
  be taken into account.

---------------------------------------------------------
Title: Dynamics of solar filaments. VI - Center-to-limb study of
    H-alpha and C IV velocities in a quiescent filament
Authors: Simon, G.; Schmieder, B.; Demoulin, P.; Poland, A. I.
1986A&A...166..319S    Altcode:
  The rotation of a stable quiescent filament from near disk center to
  the limb has been observed. Observations of intensity and velocity
  were made in H-alpha and C IV, and compared with magnetic field
  measurements. From the H-alpha observations, it is concluded that the
  filament is made up of many small scale magnetic features that are
  not coherently aligned along the neutral line. They are especially
  convoluted at the apparent 'footpoints'. The measured velocities are
  of the order of a few kilometers per second in both lines. However,
  the comparison of the standard deviations of the C IV velocities in
  and out of the filament as it rotates toward the limb shows that the
  vertical velocities in the filament are greater than the horizontal
  velocities. Measurements of velocity do not make it possible to
  distinguish between the Raadu-Kuperus (1973) or Kippenhahn-Schluter
  (1957) models for prominences because neither theory is adequately
  developed for this comparison. However, the observation of the many
  fine loops brings into question the correctness of either model.

---------------------------------------------------------
Title: Hydrogen and Helium Excitation by EUV Radiation for the
    Production of White-Light Falres
Authors: Thompson, W. T.; Poland, A. I.; Milkey, R. W.
1986BAAS...18..899T    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Ephemeral active regions and coronal bright points: A solar
    maximum Mission 2 guest investigator study
Authors: Harvey, K. L.; Tang, F. Y. C.; Gaizauskas, V.; Poland, A. I.
1986gsfc.rept.....H    Altcode:
  A dominate association of coronal bright points (as seen in He
  wavelength 10830) was confirmed with the approach and subsequent
  disappearance of opposite polarity magnetic network. While coronal
  bright points do occur with ephemeral regions, this association is a
  factor of 2 to 4 less than with sites of disappearing magnetic flux. The
  intensity variations seen in He I wavelength 10830 are intermittent
  and often rapid, varying over the 3 minute time resolution of the
  data; their bright point counterparts in the C IV wavelength 1548
  and 20 cm wavelength show similar, though not always coincident time
  variations. Ejecta are associated with about 1/3 of the dark points and
  are evident in the C IV and H alpha data. These results support the
  idea that the anti-correlation of X-ray bright points with the solar
  cycle can be explained by the correlation of these coronal emission
  structures with sites of cancelling flux, indicating that, in some
  cases, the process of magnetic flux removal results in the release of
  energy. That the intensity variations are rapid and variable suggests
  that this process works intermittently.

---------------------------------------------------------
Title: A Siphon Mechanism for Supplying Prominence Mass
Authors: Poland, A. I.; Mariska, J. T.
1986SoPh..104..303P    Altcode:
  We examine a siphon-like mechanism for moving mass from the chromosphere
  to a gravitational well at the top of a magnetic loop to form a
  prominence. The calculations assume no apriori flow velocity at the loop
  base. Instead heating in the loop legs drives the flow. The prominence
  formation process requires two steps. First, the background heating
  rate must be reduced to on the order of 1 % of the initial heating
  rate required to maintain the coronal loop. This forms an initial
  condensation at the top of the loop. Second, the heating must take
  place only in the loop legs in order to produce a pressure differential
  which drives mass up into the well at the top of the loop. The heating
  rate in the loop must be increased once the prominence has begun to
  form or full prominence densities can not be achieved in a reasonable
  time. We conclude that this heating driven siphon-like mechanism is
  feasible for producing and maintaining prominences.

---------------------------------------------------------
Title: Impulsive phase transport.
Authors: Canfield, R. C.; Bely-Dubau, E.; Brown, J. C.; Dulk, G. A.;
   Emslie, A. G.; Enome, S.; Gabriel, A. H.; Kundu, M. R.; Melrose,
   D.; Neidig, D. F.; Ohki, K.; Petrosian, V.; Poland, A.; Rieger, E.;
   Tanaka, K.; Zirin, H.
1986NASCP2439....3C    Altcode:
  Contents: 1. Introduction: motivation for transport studies, historical
  perspective, overview of the chapter. 2. Impulsive phase observations
  and their interpretation: gamma-ray emission above 10 MeV, hard
  X-ray and microwave morphology, combined soft and hard X-ray spectra,
  iron Kα emission, ultraviolet and hard X-ray emission, white light
  emission, Hα emission. 3. Theoretical studies of transport processes:
  electron beams and reverse currents, proton transport, radiative energy
  transport by amplified decimetric waves. 4. Summary.

---------------------------------------------------------
Title: On V and hard X-rays, observations and model calculations.
Authors: Poland, A. I.; Mariska, J. T.
1986NASCP2449..279P    Altcode: 1986rfsf.nasa..279P
  This paper is an amalgamation of two published works that discuss
  the observation and theoretical calculations of O V (T ≡ 250,000K)
  and hard X-rays (30 - 100 keV) emitted during flares. The papers are
  by Poland et al. (1984, see Abstr. 37.073.132) and Mariska and Poland
  (1985, see Abstr. 39.076.024). The observations of hard X-rays and
  O V show that the excitation processes for each type of emission are
  closely coupled. Except for small differences the two types of emission
  rise and fall together during a flare. Model calculations are able
  to reproduce this behavior to a large extent, only when conductive
  processes do not dominate the energy transport processes.

---------------------------------------------------------
Title: Dynamics of solar filaments. IV - Structure and mass flow of
    an active region filament
Authors: Schmieder, B.; Malherbe, J. M.; Simon, G.; Poland, A. I.
1985A&A...153...64S    Altcode:
  An active region filament near the center of the solar disk was observed
  on September 29-30, 1980, with the Multichannel Subtractive Double Pass
  Spectrograph of the Meudon solar tower and the UV Spectrograph and
  Polarimeter aboard the SMM satellite. H-alpha and C IV measurements
  are presently used to study brightness and material velocity in the
  10,000 and 100,000 K temperature ranges, and photospheric magnetograms
  are used to investigate the underlying magnetic field. Attention is
  given to the constraints imposed on possible filament structures by
  observations, as well as the expected MHD relationships.

---------------------------------------------------------
Title: Numerical Simulation of a Siphon Mechanism for Quiescent
    Prominences
Authors: Mariska, J. T.; Poland, A. I.
1985BAAS...17..842M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Energetics of a double flare on November 8, 1980
Authors: Doyle, J. G.; Byrne, P. B.; Dennis, B. R.; Emslie, A. G.;
   Poland, A. I.; Simnett, G. M.
1985SoPh...98..141D    Altcode:
  Here we complete an energy balance analysis of a double impulsive
  hard X-ray flare. From spatial observations, we deduce both
  flares probably occur in the same loop within the resolution of the
  data. For the first flare, the energy in the fast electrons (assuming
  a thick-target model) is comparable to the convective up-flow energy,
  suggesting that these are related successive modes of energy storage and
  transfer. The total energy lost through radiation and conduction, 2.0 ×
  10<SUP>28</SUP> erg, is comparable to the energy in fast electrons 2.5
  × 10<SUP>28</SUP> erg. For the second flare, the energy in the fast
  electrons is more than one order of magnitude greater than the energy
  of the convective up-flow. Total energy losses are within a factor
  of two lower than the calculated fast electron energy. We interpret
  the observations as showing that the first flare occurred in a small
  loop with fast electrons heating the chromosphere and resulting in
  chromospheric evaporation increasing the density in the loop. For the
  second flare most of the heating occurred at the electron acceleration
  site. The two symmetrical components of the Ca XIX resonance line and a
  high velocity down-flow of 115 km s <SUP>−1</SUP> observed at the end
  of the second hard X-ray burst are consistent with the flare eruption
  (reconnection) region being high in the flare loop. The estimated
  altitude of the acceleration site is 5500 km above the photosphere.

---------------------------------------------------------
Title: The Relation Between Hard X-Ray and Transition Region Line
    Emission in Solar Flares
Authors: Mariska, J. T.; Poland, A. I.
1985SoPh...96..317M    Altcode:
  Observational evidence suggests that both the hard X-ray and ultraviolet
  emission from the impulsive phase of flares result from an electron
  beam. We present the results of model calculations that are consistent
  with this theory. The impulsive phase is envisioned as occurring
  in many small magnetically confined loops, each of which maintains
  an electron beam for only a few seconds. This model successfully
  matches several observed aspects of the impulsive phase. The corona is
  heated to less than 2 × 10<SUP>6</SUP> K, maximum enhanced emission
  occurs in lines formed near 10<SUP>5</SUP> K, and there is only
  slight enhancement between 10<SUP>5</SUP> and 2 × 10<SUP>6</SUP>
  K. The slope of the observed relationship between hard X-ray and
  OV 1371 Å emission is also matched, but the relative emission is
  not. The calculations indicate that UV emission lines formed below a
  temperature of about 10<SUP>5</SUP> K will arise predominantly from
  the chromospheric region heated by the electron beam to transition
  region temperatures. Emission lines formed at higher temperatures will
  be produced in the transition region. This should be detectable in
  density-sensitive line ratios. To account successfully for the impulsive
  UV emission, the peak temperature in the impulsively heated loops must
  remain below about 2 × 10<SUP>6</SUP> K. Thus our model implies that
  the impulsive heating takes place in different loops from the hotter
  gradual phase emission.

---------------------------------------------------------
Title: Performance testing of the high altitude observatory PDS
    microdensitometer
Authors: Poland, A.; Munro, R.; Friend, D.
1984asmd.conf...19P    Altcode:
  High Altitude Observatory HAO microdensitometer undergoes monthly
  testing to assure its consistent performance. These tests check
  positional and photometric stability at the 10 micron aperture
  level. The HAO test procedure is designed to run without operator
  intervention following initial configuration of the microdensitometer
  for each subprocedure. Specialized test software is resident in
  the PDP 8. The operator selects the proper subprocedure by entering
  commands. Once computer control is established, it is not relinquished
  until the test is complete.

---------------------------------------------------------
Title: The energy relation between hard X-ray and O V emission in
    solar flares
Authors: Poland, A. I.; Orwig, L. E.; Mariska, J. T.; Auer, L. H.;
   Nakatsuka, R.
1984ApJ...280..457P    Altcode:
  The relationship between energy emitted in hard X-rays and the
  ultraviolet during the impulsive phase of solar flares provides
  an important diagnostic for understanding the energy flow from
  nonthermal to thermal. Many flares were observed from the Solar
  Maximum Mission satellite simultaneously in hard X-rays and the O V
  line at 1371 A formed at 250,000 K, providing information relevant to
  this problem. Previous work has shown that short time scale peaks in
  emission of these two types of radiation coincide in time to within 1
  s. In this work the energy relation between the two types of emission
  is investigated and it is found that for any given flare there is a
  definite relation between hard X-ray and O V emissions throughout
  the flare, but from one flare to the next this relation varies
  markedly. These differences are attributed to the initial conditions in
  the flaring loops and some exploratory model calculations are presented
  to support this hypothesis.

---------------------------------------------------------
Title: A Multiwavelength Study of a Double Impulsive Flare
Authors: Strong, K. T.; Benz, A. O.; Dennis, B. R.; Leibacher, J. W.;
   Mewe, R.; Poland, A. I.; Schrijver, J.; Simnett, G.; Smith, J. B.,
   Jr.; Sylwester, J.
1984SoPh...91..325S    Altcode:
  Extensive data from the Solar Maximum Mission (SMM) and ground-based
  observatories are presented for two flares; the first occurred at
  12:48 UT on 31 August, 1980 and the second just 3 min later. They were
  both compact events located in the same part of the active region. The
  first flare appeared as a typical X-ray flare: the CaXIX X-ray lines
  were broadened (≡ 190±40 km s<SUP>-1</SUP>) and blue shifted (≡
  60±20 km s<SUP>-1</SUP>) during the impulsive phase, and there was
  a delay of about 30 s between the hard and soft X-ray maxima. The
  relative brightness of the two flares was different depending on
  the spectral region being used to observe them, the first being the
  brighter at microwave and hard X-ray wavelengths but fainter in soft
  X-rays. The second flare showed no significant mass motions, and the
  impulsive and gradual phases were almost simultaneous. The physical
  characteristics of the two flares are derived and compared. The main
  difference between them was in the pre-flare state of the coronal plasma
  at the flare site: before the first flare it was relatively cool (3 ×
  10<SUP>6</SUP> K) and tenuous (4 × 10<SUP>9</SUP> cm<SUP>-3</SUP>),
  but owing to the residual effects of the first flare the coronal plasma
  was hotter (5 × 10<SUP>6</SUP> K) and more dense (3 × 10<SUP>11</SUP>
  cm<SUP>-3</SUP>) at the onset of the second flare. We are led to believe
  from these data that the plasma filling the flaring loops absorbed most
  of the energy released during the impulsive phase of the second flare,
  so that only a fraction of the energy could reach the chromosphere to
  produce mass motions and turbulence.

---------------------------------------------------------
Title: The Relation Between Hard X-Ray and Transition-Region Line
    Emission in Solar Flares
Authors: Mariska, J. T.; Poland, A. I.
1984BAAS...16R.543M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Development and Plans for a Solar Extreme Ultraviolet Telescope
    and Spectrograph (SEUTS)
Authors: Epstein, G. L.; Neupert, W. M.; Poland, A. I.; Thomas, R. J.
1984BAAS...16..546E    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: X-Ray Ionization During the Impulsive Phase of A Solar Flare
Authors: Waldron, W. L.; Poland, A. I.
1984BAAS...16..545W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Performance testing of the High Altitude Observatory PDS
    microdensitometer.
Authors: Poland, A.; Munro, R.; Friend, D.
1984NASCP2317...19P    Altcode:
  The High Altitude Observatory PDS microdensitometer, purchased in 1972,
  is one of the earlier machines produced. Particular features of this
  machine include: PDP-8 control, 12 bit A/D converter, high density
  log amplifier, updated locking microscope head, auto-loc, teflon
  drive screws and nuts, and high speed operation (up to 60 mm/sec). The
  microdensitometer is generally used with 10 or 50 micron apertures on 35
  mm and 70 mm film. The HAO microdensitometer undergoes monthly testing
  to assure its consistent performance. These tests are designed to check
  positional and photometric stability at the 10 micron aperture level.

---------------------------------------------------------
Title: Performance Testing of the High Altitude Observatory PDS
    Microdensitometer
Authors: Poland, A. I.; Munro, R.; Friend, D.
1984amd..conf...19P    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Magnetohydrodynamic simulation of the coronal transient
    associated with the solar limb flare of 1980, June 29, 18∶21 UT
Authors: Wu, S. T.; Wang, S.; Dryer, M.; Poland, A. I.; Sime, D. G.;
   Wolfson, C. J.; Orwig, L. E.; Maxwell, A.
1983SoPh...85..351W    Altcode:
  Soft X-ray data from the XRP experiment on SMM are used to generate
  the temperature and density in the flaring region of the 1980, June
  29 (18∶21 UT) solar flare. The temporal data (T<SUB>max</SUB> ∼-
  20 × 10<SUP>6</SUP> K and n<SUB>max</SUB> ∼- 4 × 10<SUP>11</SUP>
  cm<SUP>−3</SUP>), together with an assumed velocity, are used to
  simulate mass injection as the input pulse for the MHD model of Wu
  et al. (1982a, 1983a). The spatial and temporal coronal response is
  compared with the ground-based, Mark III K-coronameter observations
  of the subsequent coronal transient. The simulation produces a
  spatially-wide, large amplitude, temporarily-steepened MHD wave
  for either of the two `canonical' magnetic topologies (closed and
  open), but no shock wave. This result appears to be confirmed by the
  fact that a type II radio event was observed late in the event for
  only a few minutes, thereby indicating that a steepening wave with
  temporary, marginal shock formation, was indeed present. The density
  enhancements produced by the simulation move away from the Sun at the
  same velocity observed by the K-coronameter. However, the observation
  of the coronal transient included a rarefaction that does not appear
  in the simulation. A probable explanation for this discrepancy is the
  likelihood that the magnitude and temporal profile of the density of
  the soft X-ray emitting plasma should not have been used as part of the
  mass injection pulse. We believe that the temperature profile alone,
  as suggested by earlier simulations, might have been a necessary and
  sufficient condition to produce both the compression and rarefaction of
  the ambient corona as indicated by the K-coronameter data. Hence, the
  dense plasma observed by XRP was probably confined, for the most part,
  close to the Sun during the ∼ 17 min duration of the observations.

---------------------------------------------------------
Title: Physical Conditions in a Quiescent Prominence Derived
    from Ultraviolet Spectra Obtained with the UVSP Instrument on the
    Solar-Maximum
Authors: Poland, A. I.; Tandberg-Hanssen, E.
1983SoPh...84...63P    Altcode:
  A quiescent prominence observed above the north-west limb on November
  20, 1980, is analyzed using data obtained with the Ultraviolet
  Spectrometer and Polarimeter (UVSP) on the Solar Maximum Mission
  (SMM). The spectral data include the lines 1215 Å of HI, 1401 Å of
  OIV, 1402 Å of SiIV, 1548 Å of CIV, 1640 Å of HeI, and 1655 Å of
  CI. From an analysis of these lines and their emission patterns we
  deduce physical characteristics of the prominence plasma, and suggest
  in particular that the prominence consisted of flux tubes at various
  temperatures. In the hotter parts of the plasma the number density
  reached values of about 3 × 10<SUP>11</SUP> cm<SUP>#X2212;3</SUP>.

---------------------------------------------------------
Title: Relation Between Hard X-ray and OV Energy Emitted During
    Solar Flares
Authors: Poland, A. I.; Orwing, L. E.; Mariska, J. T.; Auer, L. H.
1983BAAS...15..713P    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Simultaneous ultraviolet line and hard X-ray bursts in the
    impulsive phase of solar flares
Authors: Woodgate, B. E.; Shine, R. A.; Poland, A. I.; Orwig, L. E.
1983ApJ...265..530W    Altcode:
  Several fast impulsive phase solar flare bursts were observed by
  the Solar Maximum Mission instruments on 1980 November 8. The bursts
  were seen to be coincident in the O V 1371 Å line formed at 2.5 ×
  10<SUP>5</SUP> K and in 25-300 keV X-rays, to within the resolution
  time of 1 s. This lack of time difference is inconsistent with models
  for these flares in which the hard X-rays are produced at the top of
  a loop, followed by the formation of a thermal conduction front which
  travels to the footpoint where a UV burst is produced by heating. Models
  in which both X-rays and UV radiation are produced at the footpoint,
  or an electron beam transmits energy between loop top and footpoint
  is less than 1 s, are allowed.

---------------------------------------------------------
Title: Ultraviolet Observations of Solar Flares
Authors: Poland, A. I.
1982Obs...102..123P    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The Impulsive and Gradual Phases of a Solar Limb Flare as
    Observed from the Solar Maximum Mission Satellite
Authors: Poland, A. I.; Machado, M. E.; Wolfson, C. J.; Frost,
   K. J.; Woodgate, B. E.; Shine, R. A.; Kenny, P. J.; Cheng, C. C.;
   Tandberg-Hanssen, E. A.; Bruner, E. C.; Henze, W.
1982SoPh...78..201P    Altcode:
  Simultaneous observations of a solar limb flare in the X-ray and
  ultraviolet regions of the spectrum are presented. Temporal and
  spectral X-ray observations were obtained for the 25-300 keV range
  while temporal, spectral, and spatial X-ray observations were obtained
  for the 30-0.3 keV range. The ultraviolet observations were images
  with a 10″ spatial resolution in the lines of O v (T<SUB>e</SUB>
  ∼ 2.5 × 10<SUP>5</SUP> K) and Fe XXI (T<SUB>e</SUB> ∼ 1.1 ×
  10<SUP>7</SUP> K). The hard X-ray and O v data indicate that the
  impulsive phase began in the photosphere or chromosphere and continued
  for several minutes as material was ejected into the corona. Impulsive
  excitation was observed up to 30 000 km above the solar surface at
  specific points in the flare loop. The Fe XXI observations indicate a
  preheating before the impulsive phase and showed the formation of hot
  post-flare loops. This later formation was confirmed by soft X-ray
  observations. These observations provide limitations for current
  flare models and will provide the data needed for initial conditions
  in modeling the concurrent coronal transient.

---------------------------------------------------------
Title: Coronal activity below 2 solar radii - 1980 February 15-17
Authors: Fisher, R. R.; Poland, A. I.
1981ApJ...246.1004F    Altcode:
  Coronal observations concerning the area between the solar surface
  and 2.0 solar radii can now be conducted by making use of a new
  ground-based K-coronameter and a prominence monitor on Mauna Loa in
  Hawaii. Observations made by the K-coronameter on three consecutive
  days surrounding the eclipse of 1980 February 16 show that the solar
  corona was very active during this time. Definite changes occurred
  between each day's observations. During one period of K-coronameter
  observations (1980 February 15) a coronal transient was observed to move
  through the coronameter's field of view. A description is presented of
  the general changes which occurred in the corona during this period,
  taking into account the coronal transient observed by the prominence
  monitor and K-coronameter. The most important aspects of these new
  observations pertain to the relationship between the H alpha prominence
  and the surrounding coronal material.

---------------------------------------------------------
Title: The Evolution of a Coronal Streamer and the Photospheric
    Magnetic Field
Authors: Poland, A. I.; MacQueen, R. M.
1981SoPh...71..361P    Altcode:
  A large equatorial coronal streamer observed in the outer corona
  (3R<SUB>⊙</SUB>) grew in brightness and size during successive limb
  passages between October 6, 1973 and January 10, 1974 (solar rotations
  1606-1611). Unlike previous studies of streamers and their photospheric
  associations, no definite surface feature could be identified in the
  present case. This suggests that the streamer is associated with the
  large scale photospheric magnetic field. Comparison of the streamer
  growth with observed underlying photospheric magnetic flux changes
  indicated that as the streamer increased in brightness, areal extent,
  and density, the photospheric magnetic flux decreased. Three possible
  explanations for the streamer's growth are presented; the conceptually
  simplest being that the decrease in photospheric field results in an
  opening of the flux tubes under the streamer which permits an increased
  mass flux through the streamer.

---------------------------------------------------------
Title: New Mauna Loa coronagraph systems
Authors: Fisher, R. R.; Lee, R. H.; MacQueen, R. M.; Poland, A. I.
1981ApOpt..20.1094F    Altcode:
  A new set of instruments, consisting of two coronagraph systems,
  has been installed and is operating at the Mauna Loa Observing
  Station, Hawaii. The instruments are the 23-cm objective Mark III
  K-coronameter (K-III) system, a photoelectric instrument used to
  observe the inner solar corona from 1.2 R0 to 2.2 R0 and the 12.5-cm
  objective Prominence Monitor system used for the detection of H-alpha
  limb activity. New features of the K-coronameter system include the
  use of achromatic wave plates for wide bandpass operation and linear
  diode array detectors. Raster scans of the coronal image are obtained
  in 1.5 min for a critical sampling scheme of 20-sec of arc resolution
  (10 x 10-sec of arc pixels) in the coronal pB image. This represents
  a 350 information gain factor for each detection channel when compared
  with the previous Mauna Loa K-coronameters.

---------------------------------------------------------
Title: Coronal Transients Near Sunspot Maximum
Authors: Poland, A. I.; Howard, R. A.; Koomen, M. J.; Michels, D. J.;
   Sheeley, N. R., Jr.
1981SoPh...69..169P    Altcode:
  The Naval Research Laboratory's most recent Earth-orbiting coronagraph,
  called Solwind, has been observing the Sun's outer corona (2.6-10.0
  R<SUB>⊙</SUB>) at 10-min intervals since March 28, 1979. These
  observations provide the first comprehensive view of coronal transients
  near the peak of a sunspot cycle. Six, well-defined transients in
  our quick-look data have masses ranging from 7 × 10<SUP>14</SUP>
  g to 2 × 10<SUP>16</SUP> g and outward speeds ranging from 150 km
  s<SUP>−1</SUP> to 900 km s<SUP>−1</SUP>. These values are comparable
  to the ones that were obtained with the OSO-7 and Skylab observations
  during the declining phase of the last sunspot cycle. Although the
  amount of quick-look data is not sufficient to provide meaningful
  statistics, the coronal transients near sunspot maximum seem to occur
  with a greater frequency and a wider latitude range than the transients
  during the declining phase of the cycle. In both eras, there is a good,
  but imperfect, association between the occurrence of coronal transients
  and surface phenomena such as eruptive prominences and flares.

---------------------------------------------------------
Title: Changes in the Characteristics of the Coronal Plasma During
    Two Impulsive Flares
Authors: Strong, K. T.; Sylwester, J.; Parmar, A.; Dennis, B.;
   Poland, A.
1980BAAS...12R.911S    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The Development of Flares Observed in the Spectral Lines OV
    1371 Å, FeXXI 1354 Å, and in Hard X-Rays
Authors: Woodgate, B. E.; Bruner, E. C.; Cheng, C. C.; Dennis, B. R.;
   Gurman, J. B.; Frost, K. J.; Hyder, C. L.; Kiplinger, A.; Mason,
   H. E.; Orwig, L. E.; Poland, A. I.; Schoolman, S. A.; Shine, R. A.;
   Tandberg-Hanssen, E. A.
1980BAAS...12..911W    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: UV Observations of the June 29, 1980 Flare at 18:24UT
Authors: Poland, A. I.; Woodgate, B. E.; Shine, R. A.; Frost, K. J.;
   Kenny, P.; Bruner, E. C.; Wolfson, J.; Cheng, C. C.; Tandberg-Hanssen,
   E. A.; Gurman, J.; Henze, W.; Machado, M.
1980BAAS...12..903P    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The observation of a high-latitude coronal transient
Authors: Sheeley, N. R., Jr.; Howard, R. A.; Koomen, M. J.; Michels,
   D. J.; Poland, A. I.
1980ApJ...238L.161S    Altcode:
  On 1979 September 27 NRL's earth-orbiting coronagraph (Solwind)
  observed a coronal mass ejection whose outward direction in the plane
  of the sky was within 12 deg of the sun's north polar axis. Such
  high-latitude transients were not observed by the OSO 7 and Skylab
  coronagraphs during the declining phase of the last sunspot cycle,
  but may be relatively common near sunspot maximum.

---------------------------------------------------------
Title: K-coronameter observations of the solar corona, 15 - 16
    February 1980.
Authors: Fisher, R.; Poland, A. I.
1980BAAS...12..750F    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Radio and white-light observations of the 1973 August 21
    coronal transient.
Authors: Gergely, T. E.; Kundu, M. R.; Munro, R. H.; Poland, A. I.
1979ApJ...230..575G    Altcode:
  A coronal transient, which occurred on August 21, 1973, has
  been observed simultaneously in white light and at decameter
  radio wavelengths. The radio observations were obtained with a
  two-dimensional swept-frequency array (called the Teepee Tee). The
  white-light observations consist of a series of photographs taken by
  the High Altitude Observatory's coronagraph aboard Skylab. The radio
  emission associated with the transient was continuum in nature and
  lasted for almost 5 hours. The source of emission was observed to be
  cospatial with the lower part of one of the secondary white-light
  loops. A lower limit of 0.6 solar radius for the depth (extension
  along the line of sight) of this part of the transient was derived
  from considerations of radio-wave propagation in the corona. The radio
  source showed no dispersion of height with frequency, and, therefore,
  the emission is attributed to gyrosynchrotron radiation. Based on this
  assumption, the magnetic-field strength in the lower part of the loop
  is estimated to be in the 2.0-4.5-gauss range at a height of 2.1 solar
  radii from the center of the sun.

---------------------------------------------------------
Title: The association of coronal mass ejection transients with
    other forms of solar activity.
Authors: Munro, R. H.; Gosling, J. T.; Hildner, E.; MacQueen, R. M.;
   Poland, A. I.; Ross, C. L.
1979SoPh...61..201M    Altcode:
  Coronal mass ejection transients observed with the white light
  coronagraph on Skylab are found to be associated with several other
  forms of solar activity. There is a strong correlation between
  such mass ejection transients and chromospheric Hα activity, with
  three-quarters of the transients apparently originating in or near
  active regions. We infer that 40% of transients are associated with
  flares, 50% are associated with eruptive prominences solely (without
  flares), and more than 70% are associated with eruptive prominences or
  filament disappearances (with or without flares). Nine of ten flares
  which displayed apparent mass ejections of Hα-emitting material from
  the flare site could be associated with coronal transients. Within
  each class of activity, the more energetic events are more likely to
  be associated with an observable mass ejection.

---------------------------------------------------------
Title: Mass flow in loop type coronal transients.
Authors: Anzer, U.; Poland, A. I.
1979SoPh...61...95A    Altcode:
  The white light coronagraph on Skylab observed many loop type coronal
  transients. These loops travel through the coronagraph's field of view
  (2-6R<SUB>⊙</SUB>) over a period of a few hours, after which the legs
  of the loops usually remain visible for a few days. In this paper we
  investigate the temporal changes in density and mass per unit length
  measured along the legs of such loops during the several days after
  the initial eruption. Examination of 8 transients shows that the mass
  and density in the legs decrease during the few hours after the top of
  the loop has travelled beyond the coronagraph's field of view. The mass
  and density then increase slowly, during the next one half to one day,
  then decrease again over approximately the same period. These changes
  are generally shown to be too rapid to be explained by solar rotation,
  indicating that the transient legs have a lifetime of only a few days.

---------------------------------------------------------
Title: Physical Conditions in a Limb Flare
Authors: Fisher, R. R.; Poland, A. I.
1978BAAS...10..657F    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Motions and mass changes of a persistent coronal streamer.
Authors: Poland, A. I.
1978SoPh...57..141P    Altcode:
  A coronal streamer was observed by the white light coronagraph on
  Skylab during 5 successive limb passages between 1 June, 1973 and 6
  August, 1973. The Skylab data give independent measures of coronal
  brightness and polarization, as functions of time. These permit the
  distinction between changes in the coronal streamer's appearance
  due to solar rotation and actual structural changes. The streamer's
  visual appearance changed slightly between successive limb passages
  indicating that it was not a steady state feature. Measurements of the
  streamer's latitude, brightness, and polarization during 3 east limb
  passages show that: (1) the streamer's axis migrated southward from
  25° N at first east limb passage to 11° N at second east limb passage
  to 8° N latitude at third east limb passage; (2) the streamer's mass
  (and mass gradient with height), varied by between 20 and 50% from one
  east limb passage to the next; (3) the streamer's longitudinal extent
  was also observed to be less on successive east limb passages; and (4)
  mass changes (distinct from coronal transients) occurring over hours
  were detected during at least two limb passages. Comparison of the
  outer coronal observations with observations from lower in the solar
  atmosphere indicate that the streamer was associated with a complex of
  solar activity consisting of active regions and filaments. This complex
  of activity shifted southward by the same amount as the streamer. The
  variations detected in the streamer preclude the detailed determination
  of its three-dimensional structure.

---------------------------------------------------------
Title: Expansion and broadening of coronal loop transients: a
    theoretical explanation.
Authors: Mouschovias, T. Ch.; Poland, A. I.
1978ApJ...220..675M    Altcode:
  Consequences are examined of the assumption that an observed coronal
  loop transient is a twisted rope of magnetic-field lines expanding and
  broadening in the background coronal plasma and magnetic field. It
  is shown that the expansion can be accounted for by the azimuthal
  component of the field; the observed broadening of the loop as it
  moves outward can be accounted for by the longitudinal component of
  the field. In order to have a net outward force and at the same time
  avoid a classical pinch (sausage) instability, the two components of
  the field must satisfy a certain inequality. It is predicted that,
  as the loop rises, the width (h) of its top portion should vary
  proportionally with distance (R) from the sun's center. This is in
  good agreement with measurements that show h is proportional to the
  0.8 power of R. The prediction that the radius of curvature of the
  top portion of the loop should be proportional to R differs from the
  measured variation. The difference could be accounted for by a drag
  due to the background coronal field that flattens the loop's top.

---------------------------------------------------------
Title: Temporal evolution of the equatorial K-corona.
Authors: MacQueen, R. M.; Poland, A. I.
1977SoPh...55..143M    Altcode:
  Observations of the equatorialK-coronal radiance at 2.5R<SUB>⊙</SUB>
  from Sun center and its variation with time, on a daily basis,
  during the Skylab mission (May 1973-February 1974) are presented. The
  observations are subdivided into three periods, each characterized
  by a different variation of the radiance pattern with time. During
  the initial period, encompassing two solar rotations, there are
  several data gaps, but the radiance pattern shows a more or less
  smooth variation with time; however, during the second period (also
  about two solar rotations duration) the radiance signal is neither
  persistent on the short term nor recurrent from one limb passage to
  the next. Finally, during the last period, of five solar rotations
  duration, the radiance signal exhibits an orderly periodic behavior
  of increasing intensity. These results are interpreted as indicating
  a general simplification of the coronal magnetic field through the
  mission and, in comparison with harmonic analysis of the surface
  magnetic field (Levine, 1977), as indicating a rapid response of
  equatorial outer coronal structures to abrupt changes in the global
  surface field structure.

---------------------------------------------------------
Title: A study of the background corona near solar minimum.
Authors: Saito, K.; Poland, A. I.; Munro, R. H.
1977SoPh...55..121S    Altcode:
  The white light coronagraph data from Skylab is used to investigate
  the equatorial and polarK andF coronal components during the
  declining phase of the solar cycle near solar minimum. Measurements
  of coronal brightness and polarization brightness product between 2.5
  and 5.5R<SUB>⊙</SUB> during the period of observation (May 1973 to
  February 1974) lead to the conclusions that: (1) the equatorial corona
  is dominated by either streamers or coronal holes seen in projections
  on the limb approximately 50% and 30% of the time, respectively; (2)
  despite the domination by streamers and holes, two periods of time
  were found which were free from the influences of streamers or holes
  (neither streamers nor holes were within 30° in longitude of the limb);
  (3) the derived equatorial background density model is less than 15%
  below the minimum equatorial models of Newkirk (1967) and Saito (1970);
  (4) a spherically symmetric density model for equatorial coronal holes
  yields densities one half those of the background density model; and
  (5) the inferred brightness of theF-corona is constant to within ±10%
  and ±5% for the equatorial and polar values, respectively, over the
  observation period. While theF-corona is symmetric at 2R<SUB>⊙</SUB>
  it begins to show increasing asymmetry beyond this radius such that
  at 5R<SUB>⊙</SUB> the equatorialF-coronal brightness is 25% greater
  than the polar brightness.

---------------------------------------------------------
Title: Radiance calibration of the High Altitude Observatory
    white-light coronagraph on Skylab.
Authors: Poland, A. I.; Gosling, J. T.; MacQueen, R. M.; Munro, R. H.
1977ApOpt..16..926P    Altcode:
  The processing of over 35,000 photographs of the solar corona obtained
  by the white-light coronograph on Skylab is described. Calibration of
  the vast amount of data was complicated by temporal effects of radiation
  fog and latent image loss. These effects were compensated by imaging
  a calibration step wedge on each data frame. Absolute calibration of
  the wedge was accomplished through comparison with a set of previously
  calibrated glass opal filters. Analysis employed average characteristic
  curves derived from measurements of step wedges from many frames within
  a given camera half-load. The net absolute accuracy of a given radiance
  measurement is estimated to be 20%.

---------------------------------------------------------
Title: Measurement of stray radiance in the High Altitude
    Observatory's Skylab coronagraph.
Authors: Csoeke-Poeckh, A.; MacQueen, R. M.; Poland, A. I.
1977ApOpt..16..931C    Altcode:
  The paper outlines two techniques used for determining the instrumental
  stray radiance from orbital results obtained with the Skylab white light
  coronagraph. The first technique employs images of the lunar disk made
  near the time of solar eclipse to compare the apparent contrasts of
  maria and highlands recorded by the coronograph with those of previous
  studies and then determine the magnitude of the stray radiance and its
  variation along a radius. The second method determines the azimuthal
  variation of the stray radiance by measuring the change in the net
  radiance of a point in the coronal images as the image is rotated.

---------------------------------------------------------
Title: The Background Corona Near Solar Minimum.
Authors: Saito, K.; Poland, A.; Munro, R.; MacQueen, R.
1977BAAS....9Q.371S    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Interpretation of broad-band polarimetry of solar coronal
transients: importance of the Halpha emission.
Authors: Poland, A. I.; Munro, R. H.
1976ApJ...209..927P    Altcode:
  An eruptive prominence and coronal transient was observed in H-alpha,
  He II 304-A, and coronal white light (3700-7000 A). This event was
  generically similar to many other coronal transients associated with
  eruptive prominences in that loops of material propagated outward
  through the corona. It differed in that some of the prominence material
  was observed above 1.75 solar radii in both coronal white light and
  He II. Polarization analysis of the white-light data shows that the
  observed radiance from the loop-like transient was entirely due to
  free electron or Thomson scattering, whereas the white-light radiance
  from the prominence material was dominated by H-alpha emission. By
  comparing the white-light observations with model calculations, the
  densities along the loop and limits on the temperature and density of
  the prominence are obtained. Material observed in both white light
  and He II is shown to be cool prominence material, whereas analysis
  indicates that the transient-loop material is hot and coronal in
  origin. The time sequence of observations leads to the hypothesis that
  the prominence material is heated as it is ejected from the sun.

---------------------------------------------------------
Title: Expansion and Broadening of Coronal Loop Transients.
Authors: Mouschovias, T. Ch.; Poland, A. I.
1976BAAS....8..534M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The Structure and Fluctuations of a Coronal Streamer.
Authors: Poland, A. I.
1976BAAS....8Q.532P    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The speeds of coronal mass ejection events.
Authors: Gosling, J. T.; Hildner, E.; MacQueen, R. M.; Munro, R. H.;
   Poland, A. I.; Ross, C. L.
1976SoPh...48..389G    Altcode:
  The outward speeds of mass ejection events observed with the
  white light coronagraph experiment on Skylab varied over a range
  extending from less than 100 km s<SUP>−1</SUP> to greater than
  1200 km s<SUP>−1</SUP>. For all events the average speed within
  the field of view of the experiment (1.75 to 6 solar radii) was 470
  km s<SUP>−1</SUP>. Typically, flare associated events (Importance
  1 or greater) traveled faster (775 km s<SUP>−1</SUP>) than events
  associated with eruptive prominences (330 km s<SUP>−1</SUP>); no
  flare associated event had a speed less than 360 km s<SUP>−1</SUP>,
  and only one eruptive prominence associated event had a speed greater
  than 600 km s<SUP>−1</SUP>. Speeds versus height profiles for a
  limited number of events indicate that the leading edges of the ejecta
  move outward with constant or increasing speeds.

---------------------------------------------------------
Title: Initial Results from the High Altitude Observatory White
    Light Coronagraph on Skylab - A Progress Report
Authors: MacQueen, R. M.; Gosling, J. T.; Hildner, E.; Munro, R. H.;
   Poland, A. I.; Ross, C. L.
1976RSPTA.281..405M    Altcode: 1976RSLPT.281..405M
  The frequent, periodic observations by the white light coronagraph
  allow an examination of coronal variations over a broad range of
  temporal scales. Examples of the slowest and most rapid variations
  are presented. An example of extremely slow coronal variations is the
  gradual evolution - to a large equatorial streamer - in association
  with a marked decrease in solar activity, as the total magnetic flux
  in one hemisphere decreased. Another example is given of a long-lived
  quasi-stable coronal streamer, apparently associated with a stable
  filament channel; comparison of this streamer with coronal potential
  magnetic field computations show little correlation. The remainder
  of the paper summarizes some results on coronal transients - the most
  rapid variations observed. Characteristic mass and energies involved
  in mass ejection transients, their temporal and spatial distributions,
  their associations with surface phenomena and possible interplanetary
  signatures, and finally their role in coronal evolution are briefly
  noted.

---------------------------------------------------------
Title: Frequency of coronal transients and solar activity.
Authors: Hildner, E.; Gosling, J. T.; MacQueen, R. M.; Munro, R. H.;
   Poland, A. I.; Ross, C. L.
1976SoPh...48..127H    Altcode:
  The High Altitude Observatory's white light coronagraph aboard Skylab
  observed some 110 coronal transients - rapid changes in appearance
  of the corona - during its 227 days of operation. The longitudes
  of the origins of these transients were not distributed uniformly
  around the solar surface (51 of the 100 events observed in seven
  solar rotations arose from a single quadrant of longitude). Further,
  the frequency of transient production from each segment of the solar
  surface was well correlated with the sunspot number and Ca II plage
  (area × brightness) index in the segment, rotation by rotation. This
  correlation implies that transients occur more often above strong
  photospheric and chromospheric magnetic fields, that is, in regions
  where the coronal magnetic field is stronger and, perhaps, more
  variable. This pattern of occurrence is consistent with our belief
  that the forces propelling transient material outward are, primarily,
  magnetic. A quantitative relation between transient production from
  an area and the Zürich sunspot number appropriate to that area is
  derived, and we speculate that the relation is independent of phase
  in the solar activity cycle. If true, the Sun may give rise to as many
  as 100 white light coronal transients per month at solar cycle maximum.

---------------------------------------------------------
Title: The Speeds of Coronal Mass Ejection Events
Authors: Hildner, E.; MacQueen, R. M.; Munro, R. H.; Poland, A. I.;
   Ross, C. L.; Gosling, J. T.
1976BAAS....8R.368H    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Movie of Comet Kohoutek (1973f) as Observed Near Minimum
    Elongation by the Hao Coronagraph Aboard SKYLAB
Authors: Hildner, E.; Gosling, J. T.; MacQueen, R. M.; Munro, R. H.;
   Poland, A. I.; Ross, C. L.
1976NASSP.393..124H    Altcode: 1976IAUCo..25..124H
  No abstract at ADS

---------------------------------------------------------
Title: A search for forward scattering of sunlight from lunar
    libration clouds
Authors: Munro, R. H.; Gosling, J. T.; Hildner, E.; MacQueen, R. M.;
   Poland, A. I.; Ross, C. L.; Hopfield, A.
1975P&SS...23.1313M    Altcode:
  An attempt to determine the radiance of forward scattered sunlight
  from particles in lunar libration regions was made with the white light
  coronagraph on Skylab. The libration regions could not be distinguished
  against the solar K + F coronal background; an upper limit to the
  libration cloud radiance is determined to be 2·5 × 10 <SUP>-11</SUP>B
  <SUB>⊚</SUB>, where B <SUB>⊚</SUB> is the mean radiance of the
  solar disk. Employing a model of the particle composition and size
  distribution which has been proposed for the interplanetary medium,
  we determine upper limits for the density enhancements in the libration
  region from the upper limit of the forward scattered radiance presented
  herein. Similarly, the actual spatial density enhancement is calculated
  using the earlier observations of the libration region backscattered
  radiance (Roach, 1975). Enhancements of a factor of 10 <SUP>2</SUP>-10
  <SUP>3</SUP> are thus determined, depending upon material composition
  and size distribution used. By combining the forward and backscatter
  observations, it is possible to eliminate from consideration clouds
  whose power law particle size distribution exponent k is 2·5
  and complex index of refraction m is 1·33-0.05 i and 1·50-0.05 i
  (i.e. absorbing ice and quartz particles, respectively). Finally, the
  radiance contrast of a possible model libration cloud is calculated with
  respect to the K- and F-corona/zodiaal light background and is shown
  to be a maximum in the vicinity of solar elongation angle ∼30 deg.

---------------------------------------------------------
Title: The Emission Sources and Geometry of the Coronal Transient
    of 21 August 1973.
Authors: Poland, A. I.; Munro, R. H.
1975BAAS....7..473P    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The Large Coronal Transient of 10 June 1973. I: Observational
    Description
Authors: Hildner, E.; Gosling, J. T.; MacQueen, R. M.; Munro, R. H.;
   Poland, A. I.; Ross, C. L.
1975SoPh...42..163H    Altcode:
  During the 8.5 month flight of the High Altitude Observatory's white
  light coronagraph on board Skylab, over 100 coronal transients were
  observed. In this paper we present a description of one well observed
  loop transient, that of 10 June 1973. The transient apparently resulted
  from the eruption of a quiescent prominence on the limb; the emergence
  of a new, bipolar active region near the prominence may have caused
  the eruptior. The transient's leading edge rose from 3.6 to 5.0
  solar radii (R<SUB>⊙</SUB>) from Sun center at approximately 500 km
  s<SUP>−1</SUP> during the 32 min of coronagraph observations. Material
  in a pre-existing streamer was swept away by the transient, causing
  the streamer to disappear. The mass ejected into the corona above a
  projected height of 2 R<SUB>⊙</SUB> was ≈ 5.4 × 10<SUP>15</SUP> g,
  the potential energy associated with the ejected transient material was
  ⩾7.0 × 10<SUP>30</SUP> erg, and the kinetic energy of the ejected
  material is estimated as 1.7 × 10<SUP>30</SUP> erg. The 10 June 1973
  transient was, in most respects, typical of other loop transients
  observed by Skylab.

---------------------------------------------------------
Title: Observations of a Long Lived Coronal Streamer
Authors: Poland, A. I.
1975BAAS....7..356P    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Direct Observations of a Flare Related Coronal and Solar
    Wind Disturbance
Authors: Gosling, J. T.; Hildner, E.; MacQueen, R. M.; Munro, R. H.;
   Poland, A. I.; Ross, C. L.
1975SoPh...40..439G    Altcode:
  Numerous mass ejections from the Sun have been detected with orbiting
  coronagraphs. Here for the first time we document and discuss the direct
  association of a coronagraph observed mass ejection, which followed a
  2B flare, with a large interplanetary shock wave disturbance observed
  at 1 AU. Estimates of the mass (2.4 × 10<SUP>16</SUP> g) and energy
  content (1.1 × 10<SUP>32</SUP> erg) of the coronal disturbance are
  in reasonably good agreement with estimates of the mass and energy
  content of the solar wind disturbance at 1 AU. The energy estimates as
  well as the transit time of the disturbance are also in good agreement
  with numerical models of shock wave propagation in the solar wind.

---------------------------------------------------------
Title: Reticulation: effects and cure.
Authors: Poland, A. I.; Gosling, J. T.
1975AASPB...9...14P    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Photography of comet Kohoutek by Skylab white light
    coronagraph.
Authors: MacQueen, R. M.; Gosling, J. T.; Hildner, E.; Munro, R. H.;
   Poland, A. I.; Ross, C. L.; Keller, H. U.; Schmidt, H. U.
1975NASSP.355...19M    Altcode: 1975coko.conf...19M
  No abstract at ADS

---------------------------------------------------------
Title: Mass ejections from the Sun: A view from Skylab
Authors: Gosling, J. T.; Hildner, E.; MacQueen, R. M.; Munro, R. H.;
   Poland, A. I.; Ross, C. L.
1974JGR....79.4581G    Altcode:
  More than 30 instances of sudden mass ejections from the sun were
  observed with the white light coronagraph experiment aboard Skylab
  during the first 118 days of the mission. Typically, these ejections
  appear as large magnetic loops rooted at the sun, yet expanding
  outward through the solar corona at speeds of the order of 400 km
  s<SUP>-1</SUP>. The loops always appear to retain their magnetic
  connection to the sun. Eighteen of these ejections were associated
  with active and eruptive prominences and surges; only three ejections
  appear to have been flare initiated. Associations with ground-detected
  metric wavelength type 2 and 4 radio bursts occur for about 30% of these
  events; however, ground-detected type 2 and 4 radio bursts originating
  near the limb are almost invariably accompanied by coronagraph-observed
  ejections. Pressure or MHD waves run out ahead of the transient material
  ejecta; at times these waves can be detected by their effects on nearby
  coronal structures. For one event, that of August 10, 1973, we make
  the following estimates: (1) mass content, 4 × 10<SUP>15</SUP> grams;
  (2) mass flow rate, 1.1 × 10<SUP>12</SUP> grams s<SUP>-1</SUP> (3)
  energy content, 8.4 × 10<SUP>30</SUP> ergs; and (4) energy flow rate,
  7.7 × 10<SUP>26</SUP> ergs s<SUP>-1</SUP>. Locally, this represents
  a significant mass and energy input to the solar wind; we suggest that
  the ejections are the coronal counterparts of nonrecurrent (including
  shocks) solar wind disturbances detected near the orbit of the earth.

---------------------------------------------------------
Title: Theoretical Helium i Emission-Line Intensities for Quiescent
    Prominences
Authors: Heasley, J. N.; Mihalas, Dimitri; Poland, A. I.
1974ApJ...192..181H    Altcode:
  Self-consistent solutions of the combined statistical equilibrium
  and transfer equations have been carried out for a rather
  complete multilevel, multi-ion model helium atom in model quiescent
  prominences. The excitation and ionization of both He I and He ii were
  considered simultaneously, and detailed calculations of the radiative
  transfer in the resonance lines and ground-state continua of both
  these ions were made, allowing for the effects of overlapping hydrogen
  transitions. A large number of excited states have been included in the
  computation, so that a fairly comprehensive set of predicted subordinate
  line intensities are now available for comparison with observation. A
  preliminary comparison of the predicted values with published singleti
  triplet ratio observations shows good agreement for all the pairs of
  lines considered. Subject headings: atomic processes - line formation -
  prominences, solar

---------------------------------------------------------
Title: The High Altitude Observatory White Light Coronagraph
    Experiment
Authors: MacQueen, R. M.; Gosling, J. T.; Hildner, E.; Munro, R. H.;
   Poland, A. I.; Ross, C. L.
1974IAUS...57..505M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Theoretical helium I emission line intensities for quiescent
    prominences.
Authors: Heasley, J. N.; Mihalas, D.; Poland, A. I.
1974BAAS....6..219H    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The High Altitude Observatory white light coronagraph
Authors: MacQueen, R. M.; Gosling, J. T.; Hildner, E.; Munro, R. H.;
   Poland, A. I.; Ross, C. L.
1974SPIE...44..207M    Altcode:
  Most of the instruments of the Apollo Telescope Mount are
  satellite-borne because they observe in regions of the electromagnetic
  spectrum where the telluric atmosphere is opaque. For the coronagraph of
  the High Altitude Observatory, observing in visible light, this is not
  so. The structure of the solar corona is obscured from ground-based
  observations by scattered light in the earth's atmosphere, and
  observations from space are required to reduce this scattered light
  to a level which is negligible with respect to the brightness of the
  outer solar corona.

---------------------------------------------------------
Title: The eruptive prominence of August 21, 1973 observed from
    Skylab in the white light corona and in the He II 304 Å chromosphere.
Authors: Poland, A. I.; Bohlin, J. D.; Brueckner, G. E.; Purcell,
   J. D.; Scherrer, V. E.; Sheeley, N. R.; Tousey, R.
1974BAAS....6..219P    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Theoretical Helium I Emission Line Intensities for Quiescent
    Prominences.
Authors: Heasley, J. N.; Mihalas, D.; Poland, A. I.
1974BAAS....6..220H    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The Outer Solar Corona as Observed from Skylab: Preliminary
    Results
Authors: MacQueen, R. M.; Eddy, J. A.; Gosling, J. T.; Hildner, E.;
   Munro, R. H.; Newkirk, G. A., Jr.; Poland, A. I.; Ross, C. L.
1974ApJ...187L..85M    Altcode:
  The white-light coronagraph experiment has made frequent, periodic
  observations of the solar corona from 1.5 R0 to 6.0 R0 during the Skylab
  mission, and these observations will permit the determination of the
  three-dimensional extent of coronal forms. There are several time
  scales on which visual changes in coronal structures occur, ranging
  from approximately one-half rotation to less than hours. A number of
  events corresponding to the shortest time scale - coronal transients
  - cause major restructuring of the corona. Subject headings: corona,
  solar - solar wind

---------------------------------------------------------
Title: The Eruptive Prominence of August 21, 1973 Observed from
    Skylab in the White Light Corona and in the He II 304Å Chromosphere.
Authors: Poland, A. I.; Bohlin, J. D.; Brueckner, G. E.; Purcell,
   J. D.; Scherrer, V. E.; Sheeley, N. R.; Tousey, R.
1974BAAS....6..220P    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The High Altitude Observatory white light coronagraph.
Authors: MacQueen, R. M.; Gosling, J. T.; Hildner, E.; Munro, R. H.;
   Poland, A. I.; Ross, C. L.
1974inas.conf..207M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The Outer Solar Corona as Observed from Skylab: Preliminary
    Results.
Authors: Poland, A. I.; Gosling, J. T.; Hildner, E. G.; MacQueen,
   R. M.; Munro, R. H.; Ross, C. L.
1973BAAS....5..419P    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Observations of Coronal Forms: 7 March - 7 June 1970
Authors: Hansen, R. T.; Hansen, S. F.; Newkirk, G. A.; MacQueen,
   R. M.; Gosling, J. T.; Poland, A. I.
1972BAAS....4T.383H    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Helium in hot stars
Authors: Poland, A. I.
1972Obs....92...17P    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Energy Balance in Cool Quiescent Prominences
Authors: Poland, A.; Anzer, U.
1971SoPh...19..401P    Altcode:
  The energy balance for cool quiescent prominences is examined using
  a 6000 km, 6000 K isothermal slab model prominence with a density
  gradient dictated by a modified Kippenhahn-Schlüter model. The
  model is irradiated from both sides by the coronal, chromospheric,
  and photospheric radiation fields. The radiative transfer problem is
  solved in detail for the Lyman continuum and Hα to determine the net
  radiative energy loss for hydrogen. An estimate of the energy loss for
  Ca II H and K indicates that this source of energy loss is unimportant
  when compared with the hydrogen radiation. The radiative energy loss
  is easily balanced by the conductive energy gain from the corona.

---------------------------------------------------------
Title: Hydrogen Ionization and n=2 Population for Model Spicules
    and Prominences
Authors: Poland, A.; Skumanich, A.; Athay, R. G.; Tandberg-Hanssen, E.
1971SoPh...18..391P    Altcode:
  Using slab model atmospheres that are irradiated from both sides by
  photospheric, chromospheric, and coronal radiation fields we have
  determined the ionization and excitation equilibrium for hydrogen.

---------------------------------------------------------
Title: Energy balance in quiescent prominences.
Authors: Poland, A.; Anzer, U.
1971BAAS....3..353P    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: On the Application of the Newton-Raphson Method to the
    Excitation and Transfer of Continuum Radiation
Authors: Domenico, B. A.; Poland, A. I.; Skumanich, A.
1971BAAS....3....9D    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: -Non-LTE effects for He i in early B type stars
Authors: Poland, A.; Skumanich, A.
1971MNRAS.152P..18P    Altcode:
  The contention by Hearn and Leckrone that non-LTE affects helium
  abundances derived for early main sequence stars is shown to be in
  error. Although the cores of some lines exhibit non-LTE effects, their
  equivalent widths, which are dominated by line wings that remain in
  LTE, are unaffected and yield the same helium abundances as in LTE. The
  lines A6678 and A587S have weak wings and remain affected by non-LTE.

---------------------------------------------------------
Title: The Ionization Equilibrium and the N = 2 Population of Hydrogen
    in Quiescent Prominences
Authors: Poland, A.; Athay, R. G.; Skumanich, A.; Tandberg-Hanssen, E.
1970BAAS....2R.338P    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Neutral Helium Lines and the Helium Anomaly in Hot Stars
Authors: Poland, Arthur I.
1970ApJ...160..609P    Altcode:
  Using our previously calculated departures from LTE for He r in hot
  stars we have calculated nonLTE and LTE line profiles and equivalent
  widths for the 2SAP, 2P-4S, 2P-5S, and 2P-4D transitions in the singlet
  and triplet systems of neutral helium in model atmospheres of 20000 and
  30000 K with log g = 4. In comparing the LTE and non-LTE calculations
  we found that: (1) the cores of the stronger lines are deepened by
  including non-LTE; (2) for some of the weaker lines non-LTE raises
  the core of the line; (3) the wings of the lines are formed in LTE,
  as are the forbidden components of the 2P-4D transitions; and (4) the
  equivalent widths of the lines are almost unaffected by non-LTE. Because
  the forbidden components of the 2P-4D transitions are formed in LTE
  and the allowed cores of these lines are strongly affected by non-LTE,
  we have formed a ratio of line depth in the allowed component to
  line depth in the forbidden component to compare the non-LTE effect
  wfth observations. A comparison of LTE, non-LTE, and observed ratios
  shows that only the non-LTE results agree with the observations. Since
  the equivalent widths of the lines are not affected by non-LTE, we
  have calculated LTE widths for a series of model atmospheres and have
  found that the helium anomaly can be explained by LTE alone. In fact,
  the helium anomaly is basically a strong line/weak line effect. A
  comparison of our equivalent widths with observations indicates that
  the helium abundance in early-type dwarfs is about He/H = 0.12.

---------------------------------------------------------
Title: The rotational temperature of a TiO band in the spectrum of
    R Hydrae.
Authors: Keller, C. F.; Jackson, B. V.; Poland, A. I.; Peery,
   B. F., Jr.
1970A&A.....4..415K    Altcode:
  A procedure is presented for the determination of a rotational
  temperature from observations of the (1.0) ?`8 TiO band. The method is
  based upon comparison between accurately measured wavelengths of blended
  absorption features in the band and corresponding wavelengths in the
  computed band proffle. The rotational temperature found from McDonald
  coude' spectrograms of R Hydrae is Trot = 1430 290 0K. Key words:
  R Hydrae, long period variable - molecular spectroscopy, TiO-temperature

---------------------------------------------------------
Title: Neutral helium lines and departures from LTE in hot stars
Authors: Johnson, Hollis Ralph; Poland, Arthur I.
1970PGLO...94.1151J    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Neutral helium lines and the helium anomaly in hot stars
Authors: Poland, Arthur I.
1970PGLO...98..609P    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Departures from LTE for neutral helium lines in hot stars
Authors: Poland, Arthur Ira Art
1969PhDT........91P    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Departures from LTE for Neutral Helium Lines in Hot Stars.
Authors: Poland, Arthur Ira
1969PhDT.........4P    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Neutral helium lines and departures from LTE in hot stars.
Authors: Johnson, H. R.; Poland, A. I.
1969JQSRT...9.1151J    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Calculations of Solar Hydrogen Lines: Comparative Solutions
    for a Standard Line Transfer Problem
Authors: Athay, R. G.; Avrett, E. H.; Beebe, H. A.; Johnson, H. R.;
   Poland, A. I.; Cuny, Y.
1968rla..conf..169A    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: On the Equilibrium of Hydrogen in Early-Type Stars
Authors: Beebe, H. A.; Hollis, H. R.; Poland, A. I.
1968rla..conf..393B    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Neutral Helium Lines and Departures from LTE in Hot Stars
Authors: Johnson, H. R.; Poland, A. I.
1968rla..conf..413J    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Departures from Equilibrium in Neutral Helium for Hot Stars.
Authors: Johnson, Hollis K.; Poland, Arthur I.
1968AJS....73Q.186J    Altcode:
  Departures from equilibrium for He I are calculated for theoretical
  models of early-type stars by solving self-consistently the equations
  for radiative transfer and steady state for a model atom. These
  calculations are aimed at an understanding of the observations of
  anomalous singlet/triplet intensity ratios in hot stars. Atmospheric
  models chosen are: T= 20 0000K, log g =4 (Strom, S., and Avrett, F.,
  A strophys. J. Suppl. 12, 1, 1965) and T=300000K, log g=4 (Mihalas, D.,
  Apstrophys. J. Suppl. 9, 321,1964). Various atomic models have been
  chosen in order to test their effects on the final result. Extensive
  calculations show that the singlets and triplets can be effectively
  decoupled and solved separately. Final solutions for the singlets
  involved the levels: 1S, 2S, 2P, 3, 4, 5, 6, 7-9,10-14,15-20, with
  a similar atom for the triplets. All collisional and radiative rates
  were included for all levels up to n =6. Above n =6, each level was
  connected radiatively to 2S, 2P, and 3 and collisionally to 1'S, 25, 2P,
  3, and the adjacent levels. Actual calculations show that the ignored
  transitions are unimportant for the observed lines. At the surface
  of the star (r =0), the non-LTF parameter b1= 180 for the 20 0000K
  model and bi=3.4 for the 30 0000K. Results for the 20 0000K model at a
  height where r(43-23P) = 2.4 are listed below. j bj j bj 1'S 1.17 21S
  1.41 2~S 1.30 2'P 1.41 2~P 1.22 31 1.02 33 1.05 41 1.00 43 1.00 Thus
  in the region of formation of the subordinate lines of neutral helium,
  departures from thermodynamic equilibrium are quite small for a 20 0000K
  star, in agreement with observations. Calculations are underway for a 30
  0000K star, where significant departures from equilibrium are expected.

---------------------------------------------------------
Title: Effects in the Two-Color Diagram of the Rotation of A and
    F Stars.
Authors: Peters, James G.; Poland, Arthur I.; Wrubel, Marshal H.
1966AJ.....71S.174P    Altcode:
  The method described by Collins (Astrophys. J. 138, 1134, 1963) for
  computing the observed radiation of rotating stars as a function
  of angular velocity and inclination, has been extended to include
  departures from grayness. Computed displacements of rotating A and F
  stars in the two-color diagram are compared with earlier observations
  (Kraft and Wrubel, Astrophys. J. 142, 703,1965).