Author name code: bumba
ADS astronomy entries on 2022-09-14
author:"Bumba, V."
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Title: An Insight into the Origin of Hvar Observatory
Authors: Valníček, B.; Bumba, V.; Ambrož, P.
Bibcode: 2013CEAB...37..397V
Altcode:
No abstract at ADS
Title: Synoptic observations with the Coimbra spectroheliograph
Authors: Garcia, A.; Sobotka, M.; Klvaňa, M.; Bumba, V.
Bibcode: 2011CoSka..41...69G
Altcode:
Spectroheliograms in the Astronomical Observatory of the Coimbra
University (Portugal) have been photographed in the spectral line of Ca
II K continuously since 1926 and, since 1989, spectroheliograms in Hα
have been photographed as well. Since 2007, all the spectroheliograms
have been recorded using a CCD camera. Until July 2010, about 34 000
observations in total were acquired in the spectral bands Ca II K3, Ca
II K1, Hα, red continuum, and Hα Dopplergrams (since 2009), covering
a period of 85 years (Ca II K3 line). We describe the characteristics
of the photographic and digital spectroheliograms, the statistics of
the observations, and the utilization of Coimbra spectroheliograms by
the solar community.
Title: Co ovlivňuje prùběh jedenáctiletého cyklu sluneční
aktivity Title: Co ovlivňuje prùběh jedenáctiletého cyklu
sluneční aktivity Title: What affects the evolution of the
eleven-year cycle of solar activity.
Authors: Bumba, V.; Klvaňa, M.
Bibcode: 2010nspm.conf...64B
Altcode:
In search for physical causes of the irregularities observed in the
solar activity and magnetic field distributions across the Sun and in
time we have this time focused on the study of the evolution of the last
nineteen cycles (from No.5 to No.23). The cycles can be divided into
a few types according to similariry in their time evolution. It turns
out that for cycles of similar type we find similar distributions in
space for planets like Venus and Earth, and Jupiter in particular, with
Saturn also taking a certain part. In addition, the onset of activity of
all cycles seems to be closely related to a certain position of Venus
and Earth in the ecliptic. During the maximum phase of all cycles the
relative angular separation of Venus with the Earth and Jupiter takes
its minimal values (close to zero) while during every minimum phase
it is close to 45°. As far as physics is concerned it seems so far
that the key role is played by gravity although other forces and their
fields can also assume certain roles.
Title: Spectroheliograms recorded using the new CCD camera in the
OAUC, Coimbra, Portugal
Authors: Garcia, A.; Klvaňa, M.; Sobotka, M.; Bumba, V.
Bibcode: 2010nspm.conf..206G
Altcode:
Spectroheliograms in the OAUC (Coimbra, Portugal) have been
photographed in the spectral line of Ca II continuously since 1926,
and since 1990 spectroheliograms in H-alpha have been photographed as
well. Since 2007, all the spectroheliograms are recorded using new CCD
camera. Specifications of the camera, including the new optical scheme
of the spectrograph, were presented in a previous paper (Klvana et al.,
2006). On the data recorded in 2010 we demonstrate the good quality
of spectroheliograms taken during standard observing conditions,
influence of the clouds and the effects introduced by filtering.
Title: Dynamics of Active Regions Revealed by Tracking of Doppler
Features
Authors: Švanda, M.; Sobotka, M.; Klvaňa, M.; Bumba, V.
Bibcode: 2010ASSP...19..410S
Altcode: 2010mcia.conf..410S
We investigate the large-scale horizontal dynamics of active regions in
the 23rd solar cycle. The large-scale horizontal velocity fields were
measured applying the local correlation tracking (LCT) algorithm to the
processed high-cadence full-resolution full-disc MDI Dopplergrams. We
performed the selection of NOAA active regions in the available dataset
and followed their individual evolution in time. The statistical study
of this sample gives us a unique opportunity to study the dynamics
of active regions at various stages of their evolution. In few cases,
we found behavior that is consistent with the dynamical disconnection
of sunspots from the magnetic roots.
Title: Large-scale horizontal flows in the solar
photosphere. II. Long-term behaviour and magnetic activity response
Authors: Švanda, M.; Klvaňa, M.; Sobotka, M.; Bumba, V.
Bibcode: 2008A&A...477..285S
Altcode: 2007arXiv0710.2693S
We have developed a method to map large-scale horizontal velocity
fields in the solar photosphere. The method was developed, tuned, and
calibrated using synthetic data. Now, we apply the method to the series
of Michelson Doppler Imager (MDI) Dopplergrams covering almost one
solar cycle to generate the information about the long-term behaviour
of surface flows. Our method clearly reproduces the widely accepted
properties of mean flow field components, such as torsional oscillations
and a pattern of meridional circulation. We also performed a period
analysis, however due to the data series length and large gaps we did
not detect any significant periods. The relation between the magnetic
activity and the mean zonal motion is studied. We found evidence
that the emergence of compact magnetic regions locally accelerates
the rotation of the supergranular pattern in their vicinity and that
the presence of magnetic fields generally decelerates the rotation in
the equatorial region. Our results show that active regions in the
equatorial region emerge, exhibiting a constant velocity (faster by
60 ± 9 m s-1 than the Carrington rate), suggesting that
they emerge from the base of the surface radial shear at 0.95 R_⊙,
disconnect from their magnetic roots, and slow down during their
evolution.
Title: The Modernized Spectroheliograph at Coimbra
Authors: Klvaňa, M.; Garcia, A.; Bumba, V.
Bibcode: 2007ASPC..368..549K
Altcode:
Application of CCD chips in astronomical instruments constructed for
the registration of measured data on a photographic emulsion brings
some special issues. The problems increase, if we need to digitize the
whole solar disk. The spectroheliograph of the Coimbra university has
been constructed for registration of the full-disk spectroheliograms
on a photographic emulsion. Its construction is mechanically highly
precise. Among others, it perfectly compensates the spectral line
curvature in such a way that the resulting monochromatic solar disk
is without any deformation. The compensation requires an adjustment of
the entrance and exit slits, which are both curved. The fact that
during the transition from the photographic to the CCD registration it
was necessary to preserve the original function of data registration on
a photographic emulsion brings a whole number of specific problems. It
was necessary to change the parameters of the optical system, to remove
brightness and shape deformations of the solar disk, originating from
the recording medium change. In this paper we analyze the mentioned
issues and we describe how to treat them. We also present alternative
spectroheliograph usages, for example for measuring Doppler velocities.
Title: Regularities in the Distribution of Solar Magnetic Fields
Authors: Bumba, V.; Klvaňa, M.; Garcia, A.
Bibcode: 2007ASPC..368..511B
Altcode:
We examined the distribution and concentration of the solar magnetic
fields from the Wilcox observatory synoptic charts for the whole
period of their existence (May 1976 -- February 2006). We divided them
into four latitudinal zones, studying the changes of their various
structures, density, etc. These sets of maps demonstrate striking
regularities in the photospheric magnetic field distribution with time,
continuous existence of characteristic longitudes of magnetic field
concentration and their longitudinal shift with three main rotational
periods of 26.8, 28.2, and 27.14 days. They show formation of specific
structures of background weaker fields, connected with the development
of activity complexes, polarity alternation, etc. We mention the
possible sources of found regularities in the solar activity modulation.
Title: Doppler Velocity Fields in Magnetic Structures and their
Surroundings
Authors: Klvaňa, M.; Bumba, V.; Švanda, M.
Bibcode: 2006CEAB...30...21K
Altcode:
We demonstrate the effect of a velocity shift of photospheric velocity
fields in regions filled by magnetic field compared to the velocity
fields of non-magnetic regions surrounding them. We analyse this effect
on five different types of measurements in the active region NOAA 8086
obtained by SOLMAG (Ondřejov magnetograph) in four spectral lines
on September 18, 1997. The mean value of the Doppler velocity field
in regions filled by magnetic field shows a red-shift of 40--190 m
s-1 with respect to the neighbouring non-magnetic regions.
Title: Temporal Changes of the Photospheric Velocity Fields
Authors: Klvaňa, M.; Švanda, M.; Bumba, V.
Bibcode: 2005HvaOB..29...89K
Altcode:
We analyse the influence of the planets Mercury, Venus, Earth and
Jupiter on the Doppler velocity field in the solar photosphere, using
the theory of tidal forces. We compare the measured Doppler velocity
fields estimated in a zonal area along the solar equator with the
results of the dynamical calculations. From this comparison it follows
that we do not succeed to demonstrate the presence of a velocity field,
caused by the tidal forces, in the measured data. If tidal waves in
the solar photosphere do exist, they are lost in the noise and their
horizontal velocity field probably will be under the limit of ±20
m s^{-1}.
Title: Do tidal waves exist in the solar photosphere?
Authors: Klvaňa, M.; Švanda, M.; Krivtsov, A.; Bumba, V.
Bibcode: 2004HvaOB..28..157K
Altcode:
The temporal coincidences between solar activity regularities and the
motion of some planets show that there could exist a mutual physical
relationship between both processes. One of the possible causal agents
could be the action of the gravitational field. Although the altitude
of planetary tidal waves on the Sun, following many authors, is of
the order of only one millimetre, in the case of resonance it could be
enlarged appreciably. Therefore, we decided to verify the possibility
of detection of such waves in the solar atmosphere using the earlier
developed dynamical theory of tidal waves. In this paper we present
and discuss the preliminary results, obtained from the comparison
of the velocity fields measured with the MDI instrument of the SOHO
satellite and of the velocity fields of a tidal wave calculated on
the basis of the dynamical theory.
Title: Photospheric background Doppler velocity field during the
development of active regions
Authors: Bumba, V.; Klvaňa, M.; Garcia, A.
Bibcode: 2003ESASP.535...71B
Altcode: 2003iscs.symp...71B
We investigate changes of the photospheric background Doppler velocity
field, measured by a scanning photoelectric magnetograph during the
development of several active regions. Our results demonstrate that
the whole local system of an active region's magnetic and motion field
represents some kind of disturbance of the semiregular motion patterns
of the quiet photosphere which seem to have their physical background
in the local strengthening of convection and the local concentration
of the magnetic field. In such a local Doppler motion system, the
positive (blue-shifted) Doppler motion elements are considerably
diluted (with the exception of Evershed's positive motion areas and
the active region's surroundings), while the negative (red-shifted)
elements are strongly concentrated, parallel with the distribution
of the local magnetic field. At the same time, they are cellularly
organized. The circulation below an active region and its surroundings
forms a complicated system of mutually related motions bound together
by the magnetic field.
Title: Photosphere velocity field generated by tidal forces
Authors: Krivtsov, A. M.; Klvana, M.; Bumba, V.
Bibcode: 2003ESASP.535..121K
Altcode: 2003iscs.symp..121K
However, our recent research shows correlation between the planets
disposition and the solar activity. Analysis of the astronomical
data invents the question about influence of the planetary-induced
tides on the number and distribution of the active regions on the
solar surface. In the presented work we are considering dynamical
deformation of the solar sphere induced by the action of the planetary
system. Influence of the tidal deformations on the photospherical
velocity fields and their interaction with the active regions in the
photosphere are studied.
Title: Cyclic changes of the solar global and local magnetic fields
patterns
Authors: Bumba, V.
Bibcode: 2003ESASP.535....3B
Altcode: 2003iscs.symp....3B
Grouping tendency in the magnetic flux emergence in the solar
photosphere; single local magnetic fields and complexes of
activity. Relation of the local and background large-scale magnetic
fields (global fields), dynamics of their evolution. Longitudinal
distribution and sector structure in the solar magnetic fields. Magnetic
field as a coupling factor of all layers of the solar atmosphere with
the convective zone. Reflection of the solar magnetic field changes in
the heliosphere. Regularities in the solar activity appearance. Local
and global magnetic fields during different phases of the solar activity
cycle, and variations in their longitudinal and latitudinal distribution
with time. Characteristics of such changes, quasi-biennial oscillations,
shorter-term periodicities in magnetic flux formation and solar rotation
rate variations. Reflection of the solar magnetic field cyclic and
short-term changes in the corona, in the heliospheric magnetic field
distribution and in the variation of the solar wind characteristics.
Title: Dynamics of motions in the quiet photosphere
Authors: Svanda, M.; Klvana, M.; Sobotka, M.; Bumba, V.
Bibcode: 2003ESASP.535..149S
Altcode: 2003iscs.symp..149S
We determine the vector velocity fields describing the plasma motions
in the quiet solar photosphere, using the motions of the supergranular
structures, obtained by the analysis of series of Doppler measurements
of velocity fields of the whole solar disk. It turned out that
the studied vector velocity fields can be submerged under the noise
level, originating due to the strong variability of the supergranular
structures during their life time. We describe the method we used for
the suppressing of such noise, and we bring the criterions used by
the election of free parameters. We demonstrate examples of obtained
vector velocity fields and of the resulting motions of matter on the
visible photospheric surface. We discuss different factors influencing
the reproductivness of obtained results. We construct a graph of the
dependence of the differential rotation on the heliographic latitude
from the mean vector velocity field, we got for the solar disk without
expressive magnetic fields.
Title: A CCD-based guiding and control system for solar telescopes
Authors: Klvaňa, M.; Bumba, V.; Sobotka, M.
Bibcode: 2003AN....324..305K
Altcode:
We describe a system for guiding and control of motion of solar
telescopes based on a determination of the position of the full solar
disk on a CCD chip. The system computes the position of the disk center
and, according to the difference between the instantaneous and required
positions, it controls the motion of the telescope to compensate the
deviation. The instantaneous position of the disk center is the basic
input for the telescope's guiding and coordinate system. Brightness
inhomogeneities of the solar limb caused by clouds are checked in real
time. The function of the system can be suspended automatically if the
clouds degrade the accuracy of guiding. The system also makes possible
to check the correct focus and to evaluate the image quality.
Title: System of coordinates for solar telescopes
Authors: Klvaňa, M.; Bumba, V.; Sobotka, M.
Bibcode: 2003HvaOB..27..205K
Altcode:
A system of coordinates for a solar telescope, based on the principle of
the CCD detection of the whole solar disk position, is described. The
system evaluates the position of the solar disk center and from this
position it calculates the coordinates of a point situated on the
optical axis of the telescope. The method of cloudiness testing,
as well as results of tests made, and algorithms for the coordinate
calculation in six coordinate systems are demonstrated. The function of
the system can be suspended automatically if the clouds would degrade
the accuracy of guiding.
Title: Short-term solar activity regularities
Authors: Bumba, V.; Klvaňa, M.; Garcia, A.
Bibcode: 2002ESASP.506..837B
Altcode: 2002svco.conf..837B; 2002ESPM...10..837B
We study the regularities in the development of solar activity in the
course of four cycles with the smallest activity (Nos. 13-16). On the
daily sums of sunspot areas we investigate the frequency of occurrence
and time intervals between the impulses of solar activity, and their
clusters, recalling packages of coupled waves. We also study the
real situation in activity on the solar surface. Most striking is
the repetition, after many years, of long-lasting segments of daily
area curves with the same time sequence and amplitude distribution of
activity peaks, and their packages. The lengths of the time intervals
between the peaks and minima of activity are clustered around several
discrete values. The same regularities yield the correlation of the most
characteristic packages of impulses with similarly formed features of
the whole cycle. Searching for the reasons of the found regularities,
we found certain indication of relation betwen the longitudinal
distribution of solar activity and conjunctions of the first three
planets of the solar system.
Title: Semi-empirical modelling of sunspots magnetic fields on the
basis of radio astronomical and magnetographic observations
Authors: Kaltman, T. I.; Klvana, M.; Korzhavin, A. N.; Bumba, V.
Bibcode: 2002ESASP.505..433K
Altcode: 2002IAUCo.188..433K; 2002solm.conf..433K
A semi-empirical method to model spatial configurations of sunspot
magnetic fields is presented and discussed. To calculate the strength
and diversity of the magnetic fields in the chromosphere-corona
transition region (CCTR), radio astronomy and magnetographic
observations are used. Multifrequency radio observations with
RATAN-600 allow to measure magnetic fields above sunspots using a
method described in (Akhmedov, et al. 1982). Our model calculations
confirm that the measured value is the maximum magnetic field of
the sunspot at the height of the CCTR. Two-dimensional maps of the
longitudinal component of sunspot magnetic fields at the photospheric
level produced with Ondrejov magnetograph (Czech Republic) along with
the magnetic field strength measured in the corona with RATAN-600 are
used for calculations of the strength and diversity of the magnetic
field and for the estimate of the height of the CCTR above sunspots.
Title: The depths of sunspot magnetic field sources calculated on
the basis of magnetographic measurements in two spectral lines
Authors: Klvana, M.; Kaltman, T. I.; Bumba, V.
Bibcode: 2002ESASP.505..449K
Altcode: 2002IAUCo.188..449K; 2002solm.conf..449K
We present a method of determining the depth of the source of the
magnetic field beneath a sunspot, based on semiempirical modelling and
the use of a dipole model's magnetic field space configuration. The
dipole approximation is applied to the longitudinal component of the
magnetic field measured in spectral lines Fe I 5253.47 Å and Mg I
5172.7 Å, formed at different heights of the solar atmosphere. We
give the depths of magnetic field sources for several sunspots from
active regions NOAA 9503, 9504, 9505 and 9506 observed on 21 June 2001,
and comment on the results obtained.
Title: Sunspot's magnetic and velocity field within the convective
network
Authors: Bumba, V.; Klvana, M.; Garcia, A.
Bibcode: 2002ESASP.505..365B
Altcode: 2002solm.conf..365B; 2002IAUCo.188..365B
From 81 sets of photoelectric measurements of the line-of-sight velocity
component in the Evershed effect of a regular sunspot, made during
8 days with electronically enhanced sensitivity, we have estimated
the main characteristics of the Evershed flow in the measured spot:
the motion in the center of the spot is probably slightly upwards,
it is then almost horizontal and finally, in its peripheral part,
it is possibly slightly inclined below the solar surface. We draw
attention to the existence of regular secondary structures of the
Evershed effect, surrounding the primary effect and to the mutual
unity of their motions. Together they form one physical entity, which
fits the structure of the motion field of the surrounding magnetised
photosphere well. But the whole active region's motion field represents
the same kind of disturbance of the semiregular motion patterns of the
quiet photosphere, in which the positive Doppler motion elements are
considerably diluted and the negative elements strongly concentrated
and organised. We also demonstrate the relationship of the distribution
of the active region's magnetic and negative velocity fields with the
emission patterns of the K3 Ca II and of the positive motion elements
with the dark interiors of the same K3 Ca II supergranules.
Title: Impulses of solar activity
Authors: Bumba, V.; Klvana, M.; Garcia, Adriana
Bibcode: 2002ESASP.477...83B
Altcode: 2002scsw.conf...83B
We study the development of complexes of activity during the course
of four cycles with the smallest activity (Nos. 13 - 16) for which we
have the daily sums of sunspot areas, separately for the northern and
southern hemisphere. The solar activity is characterized by isolated,
suddenly appearing increases often regularly repeated in one, or
simultaneously in both hemispheres. We refer to such sudden increases as
"impulses of solar activity", which we can observe throughout the whole
activity cycle, but best during periods of lower activity. We discuss
the main characteristics of these impulses: the occurrence frequency,
number, duration, etc. We draw attention to some regularities in
their repetition
Title: Rotation of the vector velocity field in a symmetric sunspot
Authors: Klvaňa, M.; Bumba, V.
Bibcode: 2002ESASP.477..135K
Altcode: 2002scsw.conf..135K
Vector velocity fields of some sunspots demonstrate anomalous
effects. We describe briefly the method of vector velocity field
computation from the measured Doppler velocities. We bring some examples
of such anomalous velocity effects observed in the lines Fe I-5253.47
and Mg I-5172.7 Å. The spatial structure of the observed phenomenon
resembles a whirlpool effect.
Title: Reconstruction of the Telescopes HSFA1 and HSFA2
Authors: Klvaňa, M.; Sobotka, M.; Bumba, V.
Bibcode: 2001AGM....18S1002K
Altcode:
At present, two large horizontal solar telescopes with spectrographs,
located at the Ondřejov Observatory, are undergoing an important
reconstruction. The original designation of these two identical
instruments will mostly be preserved. The telescope/spectrograph
HSFA1 will continue to be used for the measurement of solar magnetic
and velocity fields, while HSFA2 is in the process of rebuilding to a
multichannel spectrograph equipped with CCD cameras. The reconstruction
of the electronic control systems of both telescopes is the most
important item. The up-to-date electronic equipment will enable a remote
control of all functions of the instruments, will offer a large amount
of automated procedures and should be resistent to the disturbances
caused by atmospheric electricity. The whole telescope/spectrograph
control system is designed to reduce and simplify the observer's work as
much as possible. In this contribution we describe the characteristics
of both reconstructed instruments and the basics of their control.
Title: Reconstruction of the Telescopes HSFA1 and HSFA2
Authors: Klvaňa, M.; Sobotka, M.; Bumba, V.
Bibcode: 2001AGM....18.P220K
Altcode:
At present, two large horizontal solar telescopes with spectrographs,
located at the Ondřejov Observatory, are undergoing an important
reconstruction. The original designation of these two identical
instruments will mostly be preserved. The telescope/spectrograph
HSFA1 will continue to be used for the measurement of solar magnetic
and velocity fields, while HSFA2 is in the process of rebuilding to a
multichannel spectrograph equipped with CCD cameras. The reconstruction
of the electronic control systems of both telescopes is the most
important item. The up-to-date electronic equipment will enable a remote
control of all functions of the instruments, will offer a large amount
of automated procedures and should be resistent to the disturbances
caused by atmospheric electricity. The whole telescope/spectrograph
control system is designed to reduce and simplify the observer's work as
much as possible. In this contribution we describe the characteristics
of both reconstructed instruments and the basics of their control.
Title: The Role of the Magnetic Field in the Ascension of the 22nd
and 23rd Cycles of Activity
Authors: Bumba, V.; Garcia, A.; Klvaňa, M.
Bibcode: 2000SoPh..197..175B
Altcode:
The first small active regions of the last two new cycles seem to be
formed, in its very first, preparatory stage, close to the equator
with uncertain magnetic orientation, and as secondary products at the
periphery of equatorial `magnetic bubbles' of the new magnetic flux
still belonging to the old cycle. At the real beginning of the new
cycle, at the periphery of its higher-latitude `magnetic bubbles',
the opposite applies to the secondary regions of the ending cycle. It
seems that two modes of magnetic flux supply the visible layers of the
photosphere during the cycle transition phase: the emergence of the
magnetic flux from the depth of the convective zone, and the mutual
interaction of the earlier emerging fluxes, or the action of the `local
dynamo', giving rise to the new local magnetic field concentrations.
Title: Longitudinal Distribution of Solar Magnetic Fields and Activity
During the Ending and Starting Periods of Activity Cycles
Authors: Bumba, V.; Garcia, A.; Klvaňa, M.
Bibcode: 2000SoPh..196..403B
Altcode:
Studying the appearance of active regions during periods of solar
activity minima, we observed that the magnetic fields of active regions
belonging to the old and new cycle were mutually related. This was
the reason we decided to investigate the relation of the old and new
cycle activity during the two last minima in more detail. We examined
the distribution of both activities in heliographic longitude, because
the patterns of such distribution change substantially during the time
of the minimum, and we studied their relation to the distribution and
development of the global (background) magnetic field. We observed that
the active regions of the old and new cycles tended to concentrate
in the same active longitudes. The sources of their magnetic fluxes
seem to have the same heliographic longitude. The beginning of the new
cycle activity, occurring at the very beginning to a very weak degree
in the equatorial zone, and then proceeding to higher latitudes, occurs
in the magnetic field remnants of the old cycle activity. During the
transition phase, a relatively large number of small active regions
is produced by both cycles.
Title: Complexes of Activity - Basic Components of Activity Cycles
(from the Bottom of the Convective Zone till the Interplanetary Space)
Authors: Bumba, V.; Klvana, M.
Bibcode: 2000ESASP.463..289B
Altcode: 2000sctc.proc..289B
No abstract at ADS
Title: Regular and Anomalous Effects in the Magnetic and Velocity
Fields of Symmetrical Sunspots
Authors: Klvana, M.; Bumba, V.; Kaltman, T.
Bibcode: 2000HvaOB..24...97K
Altcode:
In most cases, the photoelectric measurements of magnetic fields
in sunspots with penumbrae demonstrate a classical, more or less
homogeneous distribution of the magnetic and velocity fields. But there
exist some interesting cases of anomalous effects, when in the area of a
sunspot, both the magnetic, and velocity field become very complicated,
and intricated magnetic and velocity structures, accompanied often by
large gradients develop. On the basis of our experience with modelling
vector fields in symmetrical sunspots (Klvana et al., 1998), we
specify the regular and anomalous behavior of the measured longitudinal
components of magnetic and velocity field vectors; from this we judge on
the vector configuration of both fields. We demonstrate and analyse such
anomalous effects on the leading spot of the active region NOAA 7981,
measured in the spectral lines FeI 525.347 nm and MgI 517.27 nm. In
the spectral continuum the spot appears to be more or less symmetric.
Title: Photospheric Velocity Vector Fields in Irregular Sunspots
Authors: Klvana, M.; Krivtsov, A.; Bumba, V.
Bibcode: 1999ESASP.448..313K
Altcode: 1999mfsp.conf..313K; 1999ESPM....9..313K
No abstract at ADS
Title: Determination of the Full Velocity Vector in an Asymmetric
Sunspot: the Case for Small Vertical Velocity Components
Authors: Krivtsov, A. M.; Klvana, M.; Bumba, V.; Kaltman, T. I.
Bibcode: 1999ESASP.448..325K
Altcode: 1999mfsp.conf..325K; 1999ESPM....9..325K
No abstract at ADS
Title: Magnetic Flux Emergence at the Beginning of the Present Cycle
of Activity
Authors: Bumba, V.; Garcia, A.; Klvana, M.
Bibcode: 1999ESASP.448..581B
Altcode: 1999mfsp.conf..581B; 1999ESPM....9..581B
No abstract at ADS
Title: Determination of the Velocity Vector Field in an Asymmetric
Sunspot Based on Vector Magnetograph Measurements
Authors: Krivtsov, A. M.; Hofmann, A.; Staude, J.; Klvaña, M.;
Bumba, V.
Bibcode: 1999ASPC..184..108K
Altcode:
A new method to determine the distribution of the full velocity
vector in an asymmetric sunspot is presented. Measurements of the
Doppler velocity and of the vector of the magnetic field are used as
initial data for these calculations. The determination is subdivided
into two stages: in a first step we obtain the distribution of the
velocity projection onto the solar surface, and in the second step
the orthogonal component of the velocity field is calculated. The
resulting vector velocity field is in good agreement with the basic
features of the siphon flow model of penumbral flux tubes.
Title: Medium Scale Photospheric Motion Fields
Authors: Klvana, M.; Bumba, V.; Krivtsov, A.
Bibcode: 1999ASSL..239..205K
Altcode: 1999msa..proc..205K
Analyzing the Doppler velocity measurements of the photospheric motion
fields we conclude that the vertical component of the velocity vector
in the quiet photosphere cannot be neglected.
Title: Photospheric line-of-sight velocity field under quiet Hα
filaments.
Authors: Bumba, V.; Klvaňa, M.; Rompolt, B.; Rudawy, P.
Bibcode: 1999joso.proc..190B
Altcode:
The authors present some preliminary results concerning the positional
correlation of four active region Hα filaments in their quiet phase
with the photospheric line-of-sight velocity field lying beneath them,
measured with a scanning photoelectric magnetograph.
Title: Photoelectrically measured Doppler motions in regular spots.
Authors: Bumba, V.; Klvaňa, M.
Bibcode: 1999joso.proc..109B
Altcode:
From many sets of photoelectric measurements of the line-of-sight
velocity component in the Evershed effect of several regular sunspots,
made with electronically enhanced sensitivity, the authors estimate the
main characteristics of the Evershed flow in the measured spots. These
results generally agree with the results of recent spectrographic
studies. The authors also observe the changes with time of the
velocity amplitudes and shapes of motion areas in the Evershed effect
connected with five-minute and longer oscillations. They also mention
some deviations of the Evershed flow from the generally accepted
figure. They demonstrate the existence of regular secondary structures
of the Evershed effect, surrounding the primary effect, which fits the
structure of the motion field of the surrounding photosphere well. The
authors take this as a demonstration of the close relation of the
Evershed flow with the background photospheric Doppler motion network,
reflecting convection as the physical background of the existence of
the Evershed effect, but influenced by a strong magnetic field.
Title: Velocity structures in the quiet solar photosphere.
Authors: Klvaňa, M.; Bumba, V.; Krivtsov, A.
Bibcode: 1999joso.proc..193K
Altcode:
The authors have used a special method of measurement to separate the
five-minute oscillations and the photospheric background velocity
fields. In the present note they analyze both types of velocity
structures in dependence on their distance from the solar disk
center. It follows from their analysis that the vector velocity fields
of the five-minute oscillations have an omnidirectional character,
i.e. both the vertical and the horizontal components are equally
engaged, whereas, in the background velocity fields, the horizontal
component of the velocity vector seems to dominate conspicuously over
the vertical component.
Title: Determination of the full velocity vector based on vector
magnetograph measurements in an asymmetric sunspot
Authors: Krivtsov, A. M.; Hofmann, A.; Staude, J.; Klvana, M.;
Bumba, V.
Bibcode: 1998A&A...335.1077K
Altcode:
A new method to determine the distribution of the full velocity
vector in an asymmetric sunspot is presented. Measurements of the
Doppler velocity and of the vector of the magnetic field are used as
initial data for these calculations. The determination is subdivided
into two stages: in a first step we obtain the distribution of the
velocity projection onto the solar surface, and in the second step
the orthogonal component of the velocity field is calculated. The
method has been applied to a sunspot observed from two observatories
over 7 days, that is at different positions on the solar disk and in
different phases of its development. The resulting vector velocity
field is in good agreement with the basic features of the siphon flow
model of penumbral flux tubes. The velocities are directed outwards
from the sunspot, and they have small values in the umbra and maximum
values in the central part of the penumbra, while in the outer penumbra
the velocities decrease rapidly. The vertical velocities are mainly
localized at the umbral boundary (upflows) and at the outer parts of
the penumbra (downflows).
Title: Configuration of the Velocity and Magnetic Field Vectors in
the Photosphere of Symmetrical Sunspots
Authors: Klvaña, M.; Bumba, V.; Krivtsov, A.
Bibcode: 1998ASPC..155...79K
Altcode: 1998sasp.conf...79K
No abstract at ADS
Title: Chromospheric Activity above Changing Photospheric Magnetic
and Velocity Fields of Developing Active Regions
Authors: Bumba, V.; Klvaña, M.; Kálmán, B.; Rompolt, B.; Rudawy, P.
Bibcode: 1998ASPC..155..224B
Altcode: 1998sasp.conf..224B
No abstract at ADS
Title: Solar active longitudes and longitudinal concentration of
flaring active regions
Authors: Bumba, V.
Bibcode: 1998PAICz..88....1B
Altcode:
No abstract at ADS
Title: Do sympathetic flares really exist?
Authors: Bumba, V.; Klvaňm, A.
Bibcode: 1998PAICz..88...67B
Altcode:
No abstract at ADS
Title: Why does the radio activity accompanying the flares in the
two large active regions of June 1982 differ so much?
Authors: Bumba, V.; Klvaňm, A.
Bibcode: 1998PAICz..88...21B
Altcode:
No abstract at ADS
Title: Flare activity and photoelectric measurements of magnetic
and velocity fields
Authors: Klvaňm, A.; Bumba, V.
Bibcode: 1998PAICz..88...25K
Altcode:
No abstract at ADS
Title: Interpreting the growth and destruction of a large
long-duration solar active-region complex
Authors: Bumba, V.; Garcia, A.; Jordan, S.
Bibcode: 1998A&A...329.1138B
Altcode:
In a companion paper, we show that the large limb flare and coronal
mass ejection of July 9, 1982, and other energetic events that followed
through September 4, 1982, represent the final phase in the evolution
of a large active-region complex (Jordan et al. 1997). In this paper,
we review the long-duration evolution of this complex. We begin by
showing that, before its final phase, new activity in the form of
renewed flux continued to appear for nearly two years, progressively
complicating the field topology. Observations suggest that the source
of this flux rotated almost as a rigid body. Evidence is presented
that, during the final phase of large-scale eruptions, either the
connection with the underlying source of flux is broken, or the source
itself has changed. After the flare and CME of September 4, 1982, the
magnetic field topology of the entire complex was greatly simplified,
and the area of former activity was replaced by a large coronal hole. We
conclude that this evolution and destruction of a large long-duration
active-region complex is a characteristic feature of how the global
magnetic field of the Sun changes during the solar cycle.
Title: Shadia Rifai Habbal (ed.), Robotic Exploration Close to the
Sun: Scientific Basis
Authors: Bumba, V.
Bibcode: 1997SSRv...82..469B
Altcode:
No abstract at ADS
Title: Interpreting the Large Limb Eruption of July 9, 1982
Authors: Jordan, Stuart; Garcia, Adriana; Bumba, Vaclav
Bibcode: 1997SoPh..173..359J
Altcode:
A time series of K3 spectroheliograms taken at the Coimbra Observatory
exhibits an erupting loop on the east limb on July 9, 1982 in active
region NOAA 3804. The Goddard SMM Hard X-Ray Burst Spectrometer
(HXRBS) observations taken during this period reveal a hard X-ray flare
occurring just before the loop eruption is observed, and SMS-GOES soft
X-ray observations reveal a strong long-duration event (LDE) following
the impulsive phase of the flare. A Solwind coronagram exhibits a
powerful coronal mass ejection (CME) associated with the erupting
loop. Hα flare and prominence observations as well as centimeter and
decimeter radio observations of the event are also reviewed. A large,
north-south-oriented quiescent prominence reported within the upper
part of the CME expansion region may play a role in the eruption as
well. The spatial and temporal correlations among these observations are
examined in the light of two different current models for prominence
eruption and CME activation: (1) The CME is triggered by the observed
hard X-ray impulsive flare. (2) The CME is not triggered by a flare,
and the observed soft X-ray flare is an LDE due to reconnection within
the CME `bubble'. It is concluded that this event is probably of a
`mixed' type that combines characteristics of models (1) and (2). The
July 9 event is then compared to three other energetic CME and flare
eruptions associated with the same active-region complex, all occurring
in the period July 9 through September 4, 1982. It is noted that these
four energetic events coincide with the final evolutionary phase of a
long-lasting active-region complex, which is discussed in a companion
paper (Bumba, Garcia, and Jordan, 1997). The paper concludes by
addressing `the solar flare myth' controversy in the light of this work.
Title: Why does the radio activity accompanying the flares in the
two large active regions of June 1982 differ so much?
Authors: Bumba, V.; Klvaňa, M.
Bibcode: 1997SoPh..173..111B
Altcode:
An attempt is presented to explain the large difference in the
intensity, frequency range and number of radio-activity events
following the large flares in the two complex active regions of June
1982 (NOAA 3763 and NOAA 3776). The topology of their local magnetic
fields in relation to the global solar field is discussed as one of
the main factors causing this effect. The development of a specific,
magnetically bipolar `super-region' is described.
Title: Use of the Video-Technique for Observations with a Double
Solar Telescope
Authors: Klvana, M.; Bumba, V.
Bibcode: 1997HvaOB..21..109K
Altcode:
Since several years, the staff of the solar department at the
Ondrejov Observatory monitors the solar activity with the aid of a
video-system developed for the registration and digitization of the
solar image. The system fulfils our requirements for the registration
and evaluation of solar images of a medium resolution and is not very
expensive. It is also suitable for the digitization of the earlier
obtained motion-picture materials. We describe the system, discuss
its specific behaviour and our accumulated experience.
Title: Local Solar Magnetic and Velocity Field Development and
Related Photospheric and Chromospheric Activity
Authors: Bumba, V.
Bibcode: 1996SoPh..169..303B
Altcode:
We have compiled the results of our long-term studies of the
local magnetic field and its activity development, derived from
investigating sunspot group evolution, photoelectrically measured
longitudinal magnetic and velocity fields, and measurements of
sunspot proper motions. We estimate certain regularities according
to which the magnetic and velocity fields, and photospheric, as well
as chromospheric activities develop. We speculate about the physical
background of such processes.
Title: Doppler and proper motions accompanying formation of an
additional magnetic flux in the mature solar active region (NOAA
7216).
Authors: Bumba, V.; Klvana, M.; Kalman, B.
Bibcode: 1996A&AS..118...35B
Altcode:
We document the evolution of an additional magnetic flux in the
photosphere of a fully developed sunspot group, we measure longitudinal
magnetic field, line-of-sight motions, and proper motions of sunspots in
the group during this process. We demonstrate the close correlation of
magnetic field, Doppler and proper motion singularities with the area
in which additional magnetic flux appears and the new penumbrae and
umbrae develop. We discuss the probable reasons for this fact and for
the region's weak flare activity. There exist in the group about eight
sunspots with the Evershed effect, differing in form, in dependence
on the history of development of the spot in which it is observed.
Title: The 1991 southern hemisphere complex of activity.
Authors: Bumba, V.; Klvana, M.; Kalman, B.; Garcia, A.
Bibcode: 1996A&AS..117..291B
Altcode:
We have investigated the development of a complex of activity which
took place in the southern hemisphere of the Sun between July 1991
and April 1992. The whole process culminated with the successive
formation of two large active regions with sunspot groups NOAA 6850
(September/October) and NOAA 6891 (October/November 1991), both
having complicated magnetic fields, but the former without heavy flare
activity. We observed the appearance of the individual active regions
as the consequence of the development stage of large-scale magnetic
fields in the given area of the solar surface, in connection with
their longitudinal and latitudinal distribution. We have studied the
dynamics of this development on magnetic synoptic charts, as well as
on spectroheliograms taken in the K-line of ionized calcium. Our new
observations confirm the regularities found earlier and connection
of global and local developments with convection. We think that they
could become a tool for solar activity prediction and that they could
be used for comparative studies of stellar complexes of activity.
Title: Book reviews
Authors: Humphreys, R. M.; Kemp, S.; Savonije, G.; van der Hucht,
K. A.; van der Kruit, P. C.; Miley, G.; Bumba, V.; van Nieuwkoop,
J.; van Hoolst, T.; Cox, A.; Rutten, R. J.; Kleczek, J.; de Jager,
Cornelis; Jerzykiewicz, M.; Zwaan, C.; Poedts, S.; Sakai, Jun-Ichi;
Pecker, J. -C.; Heikkila, W.; de Jong, T.; Wilson, P. R.; Müller,
E. A.; Hoyng, P.; Icke, V.; Shore, S. N.; Achterberg, A.; Lucchin, F.;
Butcher, H.; Ne'Eman, Y.; Heidmann, J.; Belton, M. J. S.; de Graauw,
Th.; Waters, L. B. F. M.; Pacini, F.; Hultqvist, B.; Akasofu, S. -I.;
Vial, J. -C.; Schatzman, E.; van der Laan, H.; Cole, K. D.; Vanbeveren,
D.; Southwood, D.; van der Klis, M.; Katgert, Peter
Bibcode: 1996SSRv...76..339H
Altcode:
No abstract at ADS
Title: The Large Limb Event of July 9, 1982
Authors: Jordan, S. D.; Garcia, A.; Bumba, V.
Bibcode: 1996AAS...188.7009J
Altcode: 1996BAAS...28..939J
An erupting prominence was observed on the East solar limb on July 9,
1982 in a series of K3 spectroheliograms taken at the Solar Observatory
in Coimbra. Events associated with this eruption were observed with
the Hard X-ray Burst Spectrometer (HXRBS) on SMM and a number of other
instruments on the ground and in space including the Solwind satellite,
which observed an energetic coronal mass ejection (CME) during the
same time-frame. An impulsive flare occurred about one hour before the
rise-time of the soft X-ray long duration event (LDE) and the apparent
rise-time of the CME. This extensive set of observations permitted
a comparison of this complex flare-erupting prominence-CME-LDE with
a model proposed by Hundhausen (1994, 'Coronal Mass Ejections,' in
"The Many Faces of the Sun," Springer-Verlag). Both similarities and
differences are noted. While the start of the CME almost certainly
follows the impulsive flare, it cannot be concluded that the flare is
the 'cause' of the CME. The importance of determining the relative rise-
times for the CME and the LDE is underscored by this study. Two other
energetic events from the same active region are also discussed. It
is concluded that no one model for the phenomenon: flare-erupting
prominence-CME-LDE is satisfactory, even for these three events.
Title: Semiempirical model of vector fields in a symmetrical sunspot.
Authors: Klvaňa, M.; Bumba, V.
Bibcode: 1996joso.proc..144K
Altcode:
No abstract at ADS
Title: The role of magnetic and motion field singularities in the
development of active regions and their flaring activities.
Authors: Bumba, V.; Klvaňa, M.; Kálmán, B.
Bibcode: 1996joso.proc..143B
Altcode:
No abstract at ADS
Title: Doppler velocity measurements made with a scanning
photoelectric magnetograph
Authors: Bumba, Václav; Klvaňa, Miroslav
Bibcode: 1995SoPh..160..245B
Altcode:
We discuss the problems connected with the measurements and
evaluation of line-of-sight velocities, obtained with a scanning
photoelectric magnetograph using a line-shifter with enhanced
sensitivity. We bring arguments for the validity of the results of our
photoelectric Doppler velocity recordings. We have found a network of
cellularly shaped patterns in the distribution of photo-electrically
measured line-of-sight motions, upflowing in the magnetically quiet
(blue-shifted) and downflowing in magnetically active (red-shifted)
areas of the photosphere, if the mean velocity level is estimated for
a sufficiently large measured area. The features of both directions
are mutually complementary. We demonstrate the effect of the shift of
the reference zero velocity level on the topology of the line-of-sight
velocity maps, and the dependence of this level on the size of the
area from which it is estimated.
Title: Coronal holes and their relation to the background and local
magnetic fields.
Authors: Bumba, V.; Klvana, M.; Sykora, J.
Bibcode: 1995A&A...298..923B
Altcode:
We correlate the evolution of coronal holes with the development of the
large-scale distribution of solar magnetic fields during the years 1991
and 1992. We see strong ties between the formation of coronal holes
and the latest stages of evolution of complexes of activity, closely
related to the regularities in the longitudinal distribution of solar
magnetic fields. We also deduce that the evolution of a coronal hole is
a global process, depending on the contemporary general stage of solar
activity, in which the equatorial and polar holes are strongly bound
together. We estimate the interrelations of coronal holes and their
magnetic fields with magnetic fields of associated active regions, and
also measure the values of the longitudinal magnetic flux. We have found
a close relation of coronal holes to older active regions which results
in the influence of the intensity and topology of the active region's
magnetic field on the resulting configuration of the lines of force of
the coronal hole's magnetic field, extending into interplanetary space.
Title: NOAA 6850: an inactive delta-configuration and its magnetic
and velocity fields.
Authors: Bumba, V.; Klvana, M.; Kalman, B.
Bibcode: 1995A&AS..109..355B
Altcode:
We present the results of a detailed study of evolution of photospheric
features, longitudinal magnetic and velocity fields and proper motions
of sunspots in one complex (NOAA 6850) and one simple (NOAA 6853)
active region of September/October 1991, being part of a long-lasting
complex of activity. We bring evidence of the changes of all the studied
quantities with the sudden renewal and then subsequent weakening
of magnetic activity in the larger group. We discuss the reasons
why the complex delta-configuration group did not produced larger
flares, assuming that the observed phase of the complex's development
represented only a preparatory stage, which matured during the next
disk passage. We underline the physical importance of the coincidence
of magnetic field, line-of-sight and proper motion singularities with
regions of the fastest changes of penumbral and umbral structures.
Title: Solar Zonal Average Magnetic Field and the Latitudes of
Sunspot Groups
Authors: Bumba, V.; Garcia, A.
Bibcode: 1994SoPh..155..257B
Altcode:
Positions of active regions estimated from observations of the whole
solar disk in CaIIKIV during the period 1977-1989 at the
Coimbra Astronomical Observatory are compared with the time-dependent
latitudinal distribution of background solar magnetic fields and with
the latitudinal shifts of boundaries of their polarities. We confirm
that the sunspot groups are located near the zonal boundaries between
the opposite polarities of the solar background magnetic field during
different phases of the two recent consecutive cycles of activity. We
demonstrate a probable connection between the increased number of
groups and the commencement of poleward migration of zonal boundaries in
both hemispheres. But the influence of the `dominant convective rolls'
seems to he still unclear. A new problem of interrelation between the
zonal and sector boundaries has also appeared.
Title: Concerning the Solar Rotation Rates Estimated Using Tracers
Authors: Bumba, V.; Klvana, M.
Bibcode: 1994SoPh..153..437B
Altcode:
We discuss some problems concerning the influence of the behavior
of background and local magnetic and velocity fields, and above all,
of interconnections and interrelations of various phenomena of solar
activity on the estimation of solar rotation rates.
Title: Data Acquisition and Processing with the Solar Magnetograph
of The Ondřejov Observatory
Authors: Klvaňa, M.; Bumba, V.
Bibcode: 1994ESOC...50..173K
Altcode: 1994hadg.conf..173K
No abstract at ADS
Title: Formation of Coronal Holes and the Global Magnetic Field
Distribution
Authors: Bumba, V.; Klvana, M.; Rusin, V.; Rybansky, M.; Buyukliev,
C. T.
Bibcode: 1994scs..conf...65B
Altcode: 1994IAUCo.144...65B
No abstract at ADS
Title: Processing of Images Acquired at the Ondřejov Double Solar
Refractor
Authors: Klvaňa, M.; Bumba, V.; Sobotka, M.
Bibcode: 1994ESOC...50..179K
Altcode: 1994hadg.conf..179K
No abstract at ADS
Title: Coronal Holes and Photospheric Magnetic Field
Authors: Bumba, V.; Klvana, M.; Sykora, I.
Bibcode: 1994scs..conf...47B
Altcode: 1994IAUCo.144...47B
No abstract at ADS
Title: Magnetic fields surrounding coronal holes
Authors: Bumba, Václav; Klvaňa, Miroslav; Sýkora, Július
Bibcode: 1994LNP...432..141B
Altcode: 1994LNPM...11..141B
During July and August 1992 we succeeded in measuring photoelectrically
longitudinal magnetic fields in areas surrounding four coronal holes,
estimated from 10830 Å spectroheliograms. We were able to estimate
values of the longitudinal magnetic flux in these areas and in their
active regions, as well as in parts of coronal holes, covered by our
measurements.
Title: About some problems concerning the estimation of solar
rotation.
Authors: Bumba, V.; Klvaňa, M.
Bibcode: 1994soro.conf..131B
Altcode:
No abstract at ADS
Title: Primary processing of data obtained by the Ondřejov
magnetograph.
Authors: Klvaňa, M.; Bumba, V.
Bibcode: 1994imfm.conf..119K
Altcode:
No abstract at ADS
Title: Contribution to the calibration of magnetic field measurements
in the line Fe I 5250.2 Å
Authors: Klvaňa, M.; Bumba, V.
Bibcode: 1994smf..conf..225K
Altcode:
No abstract at ADS
Title: Modelling of photospheric horizontal motions from Doppler
velocity measurements
Authors: Krivcova, N.; Krivcov, A.; Klvaňa, M.; Bumba, V.
Bibcode: 1994smf..conf...71K
Altcode:
No abstract at ADS
Title: Doppler velocity measurements made with a photoelectric
magnetograph
Authors: Bumba, V.; Klvaňa, M.
Bibcode: 1994smf..conf...74B
Altcode:
No abstract at ADS
Title: How does the magnetic field of an active region develop?
Authors: Bumba, V.; Klvaňa, M.
Bibcode: 1994smf..conf...52B
Altcode:
No abstract at ADS
Title: Evolution, activity, magnetic fields, line-of-sight and proper
motions in the solar active region NOAA 6659 (June 3-16, 1991)
Authors: Bumba, V.; Klvana, M.; Kalman, B.; Gyori, L.
Bibcode: 1993A&A...276..193B
Altcode:
On the basis of abundant observational data we have studied
photo spheric evolution, changes in the longitudinal magnetic
field distribution and magnetic fluxes in the large, complicated
flare-active region NOAA 6659. Special attention was given to the study
of the proper motions of its individual umbrae, and the tine-of-sight
velocities in the whole region. All the observed changes are compared
with the appearance of large, white-light flares. The development
of this AR during three preceding and two following solar rotations
is also mentioned. The velocities of the spot displacements
(varying mostly from about 10 to 100 s-1 at the most),
as well as their directions, are strongly influenced by the changes
of magnetic activity and spot formation, and by disintegration of the
group. These seem to coincide with the regions of the strong "reversed"
line-of-sight motions. In these places the mutual orientations of
the negative and positive velocity areas are "reversed", if compared
with the Evershed effect flows, occupying the whole active region. The mutual relations of these particular motions with the magnetic
field topology and the close connections of flares there with are
also discussed. Since the observed motions and magnetic fields may in
certain areas of the studied AR mutually interact, we believe that
local motions play a very significant role in its restructuring and
possibly also in its flaring capacity.
Title: What is the origin of the active region on the Sun and on
what depends its existence.
Authors: Bumba, V.
Bibcode: 1993Rise...74...64B
Altcode:
No abstract at ADS
Title: Line-of-Sight and Proper Motions in the Flaring June 1991
(NOAA 6659) Active Region
Authors: Bumba, V.; Klvana, M.; Kalman, B.; Gyori, L.
Bibcode: 1993ASPC...46..373B
Altcode: 1993mvfs.conf..373B; 1993IAUCo.141..373B
No abstract at ADS
Title: Doppler Motion in Active Regions and in the Surrounding
Photosphere
Authors: Bumba, V.; Klvana, M.
Bibcode: 1993ASPC...46...32B
Altcode: 1993mvfs.conf...32B; 1993IAUCo.141...32B
No abstract at ADS
Title: Photoelectrically measured oscillations in the photosphere.
Authors: Klvaňa, M.; Bumba, V.
Bibcode: 1993sova.conf...78K
Altcode:
No abstract at ADS
Title: Questions Concerning the Existence of Sympathetic Flares
Authors: Bumba, V.; Klvana, M.
Bibcode: 1993Ap&SS.199...45B
Altcode:
Earlier results concerning sympathetic flares - physically related
flares occurring in different active regions practically in the same
time - and time-correlated radio bursts are compared with magnetic
situation in active regions with related flaring and with the history
and dynamics of its development. We found observational evidence abou
the reality of sympathetic flares, demonstrating also that active
regions in which they appear are physically related through common
dynamical elements in which the evolution of their magnetic fields
goes parallel. Such a process may sometimes occupy a very large volume
of the photosphere and we believe that it might be related to the
large-scale convective motions.
Title: Variations of the line-of-sight motions in the quiet and
active photosphere.
Authors: Bumba, V.; Klvaňa, M.
Bibcode: 1993sova.conf...72B
Altcode:
Summarizing the results, whereas in the morphology of the line-of-sight
velocity distribution in the quiet photosphere with or without very
weak magnetic fields, the celullar-like features of motions toward
the observer (positive) are the elements prevailing there, in active
regions the positive motion areas may be observed in two cases only.
Title: Book Review: Opening the frontiers in solar research /
Pergamon, 1991
Authors: van Driel-Gesztelyi, Lidia; Bumba, V.; van Driel Gesztelyi, L.
Bibcode: 1992SoPh..141..203V
Altcode: 1992SoPh..141..203F
No abstract at ADS
Title: Book Review: Solar observations: techniques and interpretation
/ Cambridge U Press, 1991
Authors: Sanchez, I.; Bumba, V.
Bibcode: 1992SoPh..141..203S
Altcode:
No abstract at ADS
Title: Solar Active Longitudes Recurring Every 28-29 Days. Acting
Differently in Low and Higher Latitudes
Authors: Bumba, V.
Bibcode: 1991BAICz..42..381B
Altcode:
The existence of Active Longitudes (ALs) recurring every 28-29 days is
briefly discussed. These Als develop at higher heliophysical latitudes
in the same way as the 27-day ALs in the equatorial belt, but in this
equatorial belt the slowly rotating ALs acts as a trigger mechanism
of greater activity, especially when it crosses the 27-day AL.
Title: Photometry of the Umbral Structure of a Fast-developing Sunspot
Authors: Sobotka, M.; Simberova, S.; Bumba, V.
Bibcode: 1991BAICz..42..250S
Altcode:
A high-quality white-light photograph of an umbra of a large complex
spot was analyzed. Digital image processing methods were used. The
extensively inhomogeneous structure of the umbra, related to the fast
dynamics of development, displays many features (dark cores, bright
dots, light bridge, etc.), intensities and temperatures which were
studied in detail. In the dark cores a relatively low temperature was
obtained. A relation between the intensity of the individual bright
umbral dots and their dark surroundings was found.
Title: Is the recurrent enhanced geomagnetic activity preceding
the sunspot minimum related to magnetic fields of the new or old
activity cycle?
Authors: Bumba, V.
Bibcode: 1991BAICz..42..161B
Altcode:
The author compares the new index of recurrence of enhanced geomagnetic
activity with the latitudinal and longitudinal distribution of solar
magnetic fields and prominences for the recent two eleven-year cycles
of solar activity. It is demonstrated that the streamers of the solar
wind causing the considerable enhancement and regularity in recurrences
of large geomagnetic disturbances during the descending phase and
before the end of an eleven-year cycle, are anchored into the system
of magnetic fields formed by the fields of the old eleven-year cycle
of solar activity.
Title: A new index of recurrence for long-lasting enhanced geomagnetic
activity.
Authors: Bumba, V.; Hejna, L.
Bibcode: 1991BAICz..42...85B
Altcode:
A new index of recurrence for high, long-lasting enhancements of
geomagnetic activity based on the daily geomagnetic character figures
C9 is proposed and calculated. The variations of the new index values
and their periodicities are discussed. The main purpose of introducing
this new index is the possibility of improved investigations of its
correlation with the time and global distribution of various solar
activity phenomena.
Title: Low-latitude Active Longitudes on the Sun and in Interplanetary
Space
Authors: Bumba, V.; Hejna, L.
Bibcode: 1991BAICz..42...76B
Altcode:
Following a short review of the history of the development of the active
longitude concept, several graphs of the longitudinal distribution of
various low-altitude phenomena of solar activity published by various
authors were reprocessed. The inclinations of the active longitudes
found were calculated. A summary picture of all these inclinations
demonstrates the concentration of such active longitudes into two main
directions. Two values of synodic rotation: 26.77 days and 27.16 days,
corresponding to these two types of low-altitude active longitudes,
rotating faster than Carrington's rotation. The summary graph of
all active longitudes belonging to these two types shows that active
longitudes of different activity phenomena and from different authors
overlap to a relatively high degree and that they run at least through
three eleven-year cycles. The first of these active longitudes moves
around the whole sun in about 45-55 rotations and the second one in
about 200 Carringtons' rotations.
Title: Book Review: The restless sun / Smithsonian Institution
Press, 1989
Authors: Bumba, V.
Bibcode: 1990SSRv...54..451B
Altcode: 1990SSRv...54..451W
No abstract at ADS
Title: Book-Review - the Restless Sun
Authors: Wentzel, D. G.; Bumba, V.
Bibcode: 1990SSRv...54R.450W
Altcode:
No abstract at ADS
Title: Do Polar Faculae Terminate or Commence an Extended Cycle of
Solar Activity?
Authors: Bumba, V.
Bibcode: 1990BAICz..41..325B
Altcode:
The last evolutionary stage of the magnetic cycle is examined on the
basis of recent observations of polar faculae. It is concluded that
polar faculae represent the final evolutionary stage of the magnetic
cycle or a cycle of active-region formation sharply distinguished
morphologically, dynamically, and probably physically from the new
cycle.
Title: The new index of recurrence of high geomagnetic activity and
its relation to the solar activity cycle.
Authors: Bumba, V.; Heina, L.
Bibcode: 1990Ge&Ae..30..669B
Altcode:
A new index of the 27-day recurrence of large geomagnetic disturbances
over the past 100 years are proposed and calculated. Time variations
of this index are correlated with the latitudinal distribution of
solar magnetic fields and prominences during cycles 20 and 21. It is
suggested that the recurrence of high geomagnetic activity at the
solar-activity decline phase is associated with solar-wind streams
issuing from a specific solar global magnetic field configuration of
the preceding 11-year cycle.
Title: Active longitudes on the Sun and their manifestation in
interplanetary space.
Authors: Bumba, V.; Heina, L.
Bibcode: 1990Ge&Ae..30..550B
Altcode:
Longitudinal-distribution graphs of different manifestations of
solar activity are analyzed. The analysis shows the existence of two
fundamental directions of active longitudes rotating faster than the
Carrington revolution. The mean value of the synodic revolution of the
first direction is 26.77 d while that of the second direction is 27.16
d. It is suggested that both of these active longitudes are manifested
in the two fundamental inclinations of the IMF sector boundaries
demonstrated by Svalgaard and Wilcox and synodically rotating over
26.84 and 27.14 d.
Title: The Basic Cycle of Solar Activity and the Global Magnetic
Field and Active Phenomena Distribution
Authors: Bumba, V.; Hejna, L.; Rusin, V.; Rybansky, M.
Bibcode: 1990Ap&SS.170...85B
Altcode:
We have compared the latitudinal distributions of polar faculae, green
coronal emission maxima, prominences and of a new index of enhanced
geomagnetic recurrence with the distribution of magnetic fields during
the cycles Nos. 20 and 21. We did not find a distinct high-latitude
initial stage of an extended cycle in the corona, prominences and
polar faculae distribution. On the contrary, it seems that the polar
faculae and their following polarity magnetic fields represent the
last evolutionary phase of a magnetic activity cycle lasting 15 17
years. The enhanced recurrent geomagnetic activity seems to be related
to the old cycle fields. All studied phenomena clearly display two
types of latitudinal distribution: the polar belts, into which the old
following polarity fields have been transported from the equatorial
belt where both the polarities developin situ simultaneously, but in
which the leading polarity fields only remain, crossing the equator
during the minimum of activity, to play the same role on the opposite
hemispheres in the new cycle.
Title: Large-scale distribution of magnetic fields, green corona
and prominences during an extended activity cycle
Authors: Bumba, Vaclav; Rusin, Vojtech; Rybansky, Milan
Bibcode: 1990SoPh..128..253B
Altcode: 1990IAUCo.121P.253B
The interrelations of the latitudinal distribution of the coronal green
emission maxima, maximal numbers and areas of prominences, magnetic
fields, sunspots, and polar faculae in the 20th and 21st sunspot cycles
have been investigated. It is again demonstrated how the behaviour of
all studied data depends on their heliographic latitude. In the polar
zone, well separated from the equatorial we observe following polarity
magnetic fields transported only polewards, while the equatorial
zone is occupied mostly by leading polarity fields, developed there,
moving equatorwards, and crossing the equator to the other hemisphere
with the new cycle during the minimum of sunspot activity.
Title: Green Corona, Prominences and Magnetic Fields Latitudinal
Distribution During an Extended Cycle of Activity
Authors: Bumba, V.; Rusin, V.; Rybansky, M.
Bibcode: 1990BAICz..41..253B
Altcode:
The latitudinal distribution of green corona emission maxima and the
maximum frequency of prominence occurrence are presently related
to the large-scale regularities in the latitudinal distribution
of (1) magnetic fields, (2) polar faculae, and (3) sunspots. The
existence of polar and equatorial main latitudinal zones in both solar
hemispheres is demonstrated by observational data. The main magnetic
patterns are underlined by the distribution of prominences and of
green coronal emission maxima; the latter also seem to exhibit two
different qualities in their latitudinal distribution, depending on
the heliographic latitudes.
Title: Book Review: Cool stars, stellar systems and the sun. /
Springer-Verlag, 1987
Authors: Bumba, V.
Bibcode: 1990BAICz..41Q.271B
Altcode:
No abstract at ADS
Title: A new index for the recurrence of high geomagnetic activity
and the relationship between this index and the solar activity cycle.
Authors: Bumba, V.; Heina, L.
Bibcode: 1990Ge&Ae..30..565B
Altcode:
The authors propose and calculate a new index for the 27-day recurrence
of large geomagnetic disturbances for the past 100 years. The time
variation in this index is compared against the latitude distribution
of solar-magnetic fields and prominences for cycles 20 and 21. They
show that the solar-wind flows which lead to significant enhancement
of large geomagnetic disturbances and the regular recurrence period of
large geomagnetic disturbances during the decline in solar activity at
the end of each 11-year solar cycle are correlated with the magnetic
field in the preceding 11-year cycle.
Title: Active longitudes on the Sun and their reflection in
interplanetary space.
Authors: Bumba, V.; Heina, L.
Bibcode: 1990Ge&Ae..30..465B
Altcode:
Plots of the longitudinal distribution of various manifestations of
solar activity according to the papers of a number of authors are
analyzed. The slopes of the active longitudes found are calculated. A
similar plot of these slopes reveals the existence of two main
directions of active longitudes that rotate more rapidly than the
Carrington rotation. The average value of the synodic rotation of
the first direction is 26.77 days and of the second direction is
27.16 days. A combined plot of all active longitudes shows that the
active longitudes of various activity indices, and according to data of
various authors, overlap to a definite extent and that both directions
cross in the course of several 11-year cycles without interruption -
the first with a step of 45 - 55 rotations, and the second with a
step of 200 rotations of the Sun. Both these active longitudes have,
their own reflection in the two main slopes of the sector boundaries
of the IMF shown by Svalgaard and Wilcox and rotating synoptically in
26.84 and 27.44 days.
Title: Solar Active Longitudes and their Possible Relation to the
Regular Large-Scale Patterns of the Solar Magnetic Fields
Authors: Bumba, V.; Hejna, L.
Bibcode: 1990PDHO....7...92B
Altcode: 1990dysu.conf...92B; 1990ESPM....6...92B
Four groups of solar active longitudes with different synodic rotation
periods are discussed. The dynamics of their formation is studied on
the longitudinal distribution of highly integrated Stanford magnetic
charts. An attempt is made to relate them with the regular large-scale
features of the background fields visible around the time of the recent
two minima of solar activity.
Title: Photometry of the Internal Structure of a Large Umbra
Authors: Bumba, V.; Sobotka, M.; Šimberová, S.
Bibcode: 1990PDHO....7...84B
Altcode: 1990ESPM....6...84B; 1990dysu.conf...84B
An analysis of a high-resolution white-light photograph of an umbra of a
large complex main spot was performed. Digital image processing methods
were used. The umbra was observed as a very inhomogeneous structure
with large differences in intensities of the individual elements
(dark cores, bright dots, light bridge, etc.). The temperatures of
these elements were derived. It is demonstrated that the intensity
of the individual bright umbral dots is related to the intensity of
their dark surroundings.
Title: On Motions of Magnetic Fields and Induction of Activity Centers
Authors: Sattarov, I.; Bumba, V.
Bibcode: 1990PDHO....7...48S
Altcode: 1990ESPM....6...48S; 1990dysu.conf...48S
The problem of the existence of an agent exciting the appearance
of activity centers connected with the action of active longitudes
is discussed.
Title: The Patterns of the Twenty Two-Year Cycle of Solar Activity
in Sunspots Statistics and in the Global Magnetic Field and Activity
Distribution
Authors: Bumba, V.
Bibcode: 1989BAICz..40...17B
Altcode:
No abstract at ADS
Title: A Cumulative Method of Presentation of Solar Activity Secular
Changes
Authors: Bumba, V.; Hejna, L.
Bibcode: 1988BAICz..39..355B
Altcode:
A cumulative graphical method is presented for representing step-wise
secular changes in the general trends of solar activity. The cumulative
curve is divided into linear sections of several eleven-year cycles. The
inclination of this curve is used to estimate the average value
of solar relative numbers. The results are compared with previous
results (Bumba and Hejan, 1988) concerning the secular changes 22-year
periods. Observations covering almost five centuries are divided into
four periods of high activity, two periods of low activity, and three
or five periods of moderate activity. A table of these periods is
given and the implications for geophysics are discussed.
Title: Some Problems Concerning the Regularities in the Development
of the Latitudinal Distribution of Solar Magnetic Fields
Authors: Bumba, V.; Hejna, L.
Bibcode: 1988BAICz..39..363B
Altcode:
From the comparison of several modes of time development of the
latitudinal distribution of solar magnetic fields, obtained by different
authors using different basic observational material and different
methods, the authors have obtained the following results: at high solar
latitudes (|φ| ⪆ 40°) all distributions agree irrespective of the
method of construction. In zones of activity around the solar equator,
there is a qualitatively good but quantitatively poor agreement of the
integrated, directly observed fields (from Mt. Wilson Observatory) and
of the highly integrated fields derived from Hα synoptic charts. The
areas covered by the positive and negative polarities on the whole
Sun during the investigated one and half solar cycles (No. 20 and 21)
are practically equal.
Title: Geophysical consequences of solar magnetic field global
distribution and changes
Authors: Bumba, V.
Bibcode: 1988bang.iafcQ....B
Altcode:
Two special cumulative graphical methods are used here to demonstrate
the 22-year periodicity and the secular changes of solar activity
during the last five centuries. The 22-year activity changes are
related to large-scale regularities in the latitudinal and longitudinal
distribution of magnetic fields and activity on the whole solar surface
and to their reflections in interplanetary space. Fast, short-duration
changes in the field and activity distribution are studied, and it is
shown that practically every significant maximum in the flare frequency
is accompanied by a redistribution of the solar global magnetic fields,
followed by the reorganization of field sector structure and rebuilding
of coronal holes. This global magnetic field reorganization and maximum
occurrence of solar flares is related to the discrete magnetic flux
supply into the solar atmosphere mostly in the form of large complexes
of activity. The interplanetary and geophysical consequences of these
variations are considered.
Title: A Cumulative (Alternating) Method of Presentation of the
Twenty Two-Year Periodicity of Solar Activity
Authors: Bumba, V.; Hejna, L.
Bibcode: 1988BAICz..39..315B
Altcode:
A cumulative method of graphically representing the 22-year periodicity
of solar activity is presented which permits the 22-year waves of
activity to be seen as basic elements of a cumulative curve of yearly
means or observed relative numbers. The ascending branch of each wave
represents the successively summed yearly means belonging to the even
11-year cycles, while the descending branch represents yearly means
belonging to the odd 11-year cycles successively subtracted from the
above values. The method is used to investigate the mutual relations
of the individual 11-year cycles forming one 22-year cycle as well as
the secular changes in these relations. The length of the periods of
secular activity changes using the method of the correlation periodogram
is addressed.
Title: What is a "Centre of Magnetic Activity"
Authors: Bumba, V.
Bibcode: 1988BAICz..39..129B
Altcode:
The development of a characteristic magnetic field situation in the
center of sunspot groups is studied using the CSSAR observational data
set (Michard, 1968) concerning longitudinal magnetic field component
maps. It is found that a strong source of radio-emission may be formed
above the inner sector boundary. The frequencies and importances of
flares closely related to this area are proportional to the degree of
complexity of its magnetic field topology. The possible reasons for
the development of this center of magnetic activity are discussed.
Title: Formation of the White-light Flare Region of April 1984
(NOAA 4474) within the 21st Cycle of Solar Activity
Authors: Bumba, V.; Geztelyi, L.
Bibcode: 1988BAICz..39...86B
Altcode:
The principal behavior of local and background magnetic fields
accompanying the formation of the white-light flare region of April
1984, and the distribution of the fields on the solar surface during
the two last submaxima of the 21st cycle of activity (from March 1983 to
February 1985) are discussed. The large-scale activity of the fields is
summarized. It is found that the main changes in the background field
distribution on the time scale of rotations are caused by the almost
rigid body Carrington rotation and by the influence of differential
rotation on their weak remnants. It is suggested that the fields may
be related to the very large elements of convection, and/or to the
maxima of vorticity in the photospheric plasma flow.
Title: Book Review: Interstellar magnetic fields : Observation and
theory. / Springer-Verlag, 1987.
Authors: Bumba, V.
Bibcode: 1988BAICz..39..128B
Altcode:
No abstract at ADS
Title: Solar Flare Activity Changes and Global Magnetic Field
Disturbances
Authors: Bumba, V.; Hejna, L.
Bibcode: 1988BAICz..39....8B
Altcode:
Published observational data on solar-flare activity in the period
1965-1980 are analyzed statistically and related to changes in the
magnetic active longitudes (MALs) identified and studied by Bumba and
Hejna (1986). MALs are long strips of single-polarity fields which may
persist for about 8-30 rotations and display internal structure. The
data sets employed are briefly characterized, and the results are
presented graphically. Flare maxima are found to correlate well with
MAL disturbances, especially during the ascending phase of the solar
cycle and with MALs of negative polarity. The possible implications of
these findings for the interplanetary magnetic field and for theoretical
models of flare generation are indicated.
Title: Solar Global Background Magnetic Field Changes Accompanying the
Development of the White-Light Flare Region of April 1984 (NOAA 4474)
Authors: Bumba, V.; Gesztelyi, L.
Bibcode: 1988BAICz..39....1B
Altcode:
In investigating the large-scale distribution changes of solar
background magnetic field during a wide time interval around the
formation of this very complex region, it is demonstrated that this
development must be taken as part of a global process in the solar
atmosphere. Complete reorganizations are seen in the magnetic active
longitude patterns and the solar magnetic-field sector structure,
clearly related to its maximum stage. It is also shown that, at
the same time, restructuralization of coronal holes took place. The
relation of large-scale cellularlike structures to this development
is also studied. It is concluded that the formation of this strong
white-light flare region was casually related to the rebuilding of
the global solar magnetic field.
Title: Rotation of Individual Background Magnetic Field Components
During the Formation of the White-Light Flare Region of April 1984
(NOAA 4474)
Authors: Bumba, V.; Gesztelyi, L.
Bibcode: 1987BAICz..38..351B
Altcode:
In the present continuation of their study of processes related to the
development of the white-light flare region of April 1984, the authors
pay greater attention to the problem of rotation rates of certain
components of the background magnetic field, constituting the main
patterns of the weak as well as strong fields, from three points of
view: as they are demonstrated by the distribution of chromospheric
filaments, from point of view of the existence of so-called "pivot
points" (Mouradian et al., 1987) and of the rotation of the strongest
magnetic flux sources.
Title: Observation of Solar Differential Rotation with the Aid of
Magnetic Tracers
Authors: Bumba, V.; Hejna, L.
Bibcode: 1987SoPh..110..109B
Altcode:
We tried to search for the manifestation of differential rotation in
the distribution of weak remnants of magnetic fields measured with a
very low resolution. We found that, during the periods of low solar
activity and in parts of the solar photosphere with smaller density of
new magnetic flux sources, it was possible to observe the distribution
of magnetic tracers in the form of differential rotation parabolas
which increase their curvature from one rotation to the next. The
obtained differential rotation rates are not far from those given by
highly averaged sunspot data or by the daily magnetic fields. The
characteristic differential rotation parabolas as well as specific
cellular-like features disturbing their smooth patterns are always
formed from fields of one main polarity, the sign of which depends on
the phase of the activity cycle.
Title: Does the large-scale solar magnetic field distribution really
reflect the convective velocity fields?
Authors: Bumba, V.
Bibcode: 1987SoPh..110...51B
Altcode:
We have tried to decide whether the typical circular cellular-like
features, which are striking during some intervals in the large-scale
distribution of weak magnetic fields measured with low resolution, are
related to large-scale convective motions. Two scales of such patterns
were found and their morphological, kinematical and evolutionary
behaviour was estimated. Their slower and overall rotation is also
demonstrated in comparison with the rotation of highly averaged sunspot
and magnetic fields. It is difficult to explain all the observed
characteristics as random, or due to the method of field measurement
and map construction used. We also discuss the change of their magnetic
field polarities with the solar polar field reversal.
Title: Search for Giant Elements of Convection with the Aid of
Magnetic Tracers
Authors: Bumba, V.
Bibcode: 1987BAICz..38...92B
Altcode:
In this communication the author discusses once more the physical
reality of typical morphological cellular-like features of the
large-scale distribution of weak background magnetic fields measured
with low resolution. He has established several characteristic
behaviours concerning the dynamics of their development, of their
relation to differential rotation, to the frequency and intensity of
new magnetic flux sources. Their rotation as a whole, which is slower
than the differential rotation of the upper photospheric layers, and
their lifetimes speak in favour of their physical reality and their
possible relation to giant elements of convection.
Title: High flare activity and redistribution of solar global
magnetic fields.
Authors: Bumba, V.; Hejna, L.; Gesztelyi, L.
Bibcode: 1987PAICz..66..129B
Altcode: 1987eram....1..129B
The authors demonstrate that both in the global scale and in the
scale of large and complex active regions the high flare activity
is closely related to the changes in the whole background magnetic
field distribution.
Title: 10th European Regional Astronomy Meeting of the IAU, held in
Praha, Czechoslovakia, 24 - 29 August 1987. Programme of the Meeting
and Directory to the Proceedings.
Authors: Perek, L.; Zavřel, J.; Říman, J.; Bumba, V.; Lindblad,
P. O.; Huber, M. C. E.
Bibcode: 1987PAICz..65.....P
Altcode:
No abstract at ADS
Title: Does the local dynamo act in sunspot groups?
Authors: Bumba, V.
Bibcode: 1987PAICz..66...59B
Altcode: 1987eram....1...59B
The author summarizes his previous results concerning the local
magnetic field formation, showing that its sunspot groups developing
to reach higher typec C, D, E etc. continue their magnetic evolution
during the period of new magnetic flux addition immediately after
the first magnetically bipolar balanced stage. It is probably a
magnetohydrodynamical process of magnetic field strengthening or a
new magnetic flux generation. The important role of the photosphere
in all these processes is underlined.
Title: Magnetic fields of the sun and stars.
Authors: Bumba, V.
Bibcode: 1987PAICz..66....3B
Altcode: 1987eram....1....3B
The author summarizes the main results obtained by the joint effort
of solar and stellar physicists in investigating solar and solar type
activities in the low-mass main-sequence stars. He demonstrates the
basic role of the magnetic field in this activity and the importance
of its interaction with the convection and differential rotation of
each star.
Title: Solar Differential Rotation Reflected in the Distribution of
Background Magnetic Fields
Authors: Bumba, V.; Hejna, L.
Bibcode: 1987BAICz..38...29B
Altcode:
It is demonstrated that the differential rotation rates estimated with
the use of weak remnants of magnetic fields measured with a very low
resolution during the periods of low solar activity and in regions of
the photosphere with very low density of new magnetic flux sources
are between the differential rotation values obtained with the aid
of highly averaged sunspot data and from the daily magnetic field
measurements. The effects disturbing the smooth changes of solar
rotation velocity values with heliographic latitude, seen clearly in
the distribution of magnetic fields as solar differential rotation
parabolas, are briefly discussed.
Title: Scientific mission to asteroid Phaethon
Authors: Padevet, V.; Lala, P.; Bumba, V.
Bibcode: 1986inns.iafcQ....P
Altcode:
The asteroid 3200 Phaethon (previously 1983 TB) is being suggested
for direct research by interplanetary probe. The asteroid, in an
Apollo-type orbit, coincides with Geminid meteor stream and is so
far the only body known to have features of an asteroid as well as
a comet. A special program has been prepared for a desk computer to
analyze interplanetary orbits with which the asteroid could be reached
by the year 2000. Direct trajectories as well as trajectories with a
gravitational maneuver near Venus have been tested.
Title: Magnetic Field and Photospheric Development of a Particular
Sunspot Group from June 1963
Authors: Bumba, V.
Bibcode: 1986BAICz..37..281B
Altcode:
The influence of hydromagnetic and nonmagnetic forces, acting during
the process of active region formation and aging is demonstrated on
the basis of the investigation of the active region's magnetic field
and the sunspot organization and structure related to it. Especially
the existence of the short-lived peculiar photospheric filamentary
stream in its relation to the dynamics of local field evolution is
shown. Magnetic flux changes as related to flare occurrence are studied,
and a comparison of the longitudinal and transverse component of the
magnetic field with its whole vector for one day of observation is
made. The importance of the new magnetic flux development at the inner
boundary between the leading and following polarities is estimated.
Title: Formation of the May 1981 Solar Flare Complex and the Global
Magnetic Field of the Sun (H. R. 17 644)
Authors: Bumba, V.
Bibcode: 1986BAICz..37..210B
Altcode:
The degree to which the development of the May 1981 flare complex
is related to the global changes of the solar background magnetic
fields is studied. It is connected with the action of magnetic active
longitudes, it lasts about 10 rotations, and in its last phase it forms
a coronal hole. Its fields play a role in forming two sectors in the
equatorial background fields and are involved in the fast global field
redistribution into regular morphological patterns. All regularities
found require physical interpretation.
Title: Kinematics of the May 1981 Flare Complex's Magnetic Field
Decrease (H. R. 17 644)
Authors: Bumba, V.; Kálmán, B.; Klvaňa, M.; Suda, J.
Bibcode: 1986BAICz..37..219B
Altcode:
Characteristic details of the postmaximum dissolution process of
magnetic and photospheric patterns of the May 1981 flare complex are
studied over about one week of fine-scale observations. Magnetic-flux
and area changes in the course of field-topology simplification
are estimated. In the photosphere only five features with a more
stable field configuration survived this evolutionary stage. Flare
activity variations are related to the individual changes observed
in the magnetic field topology and photospheric morphology, and some
conclusions concerning the consumption of magnetic energy stored in
the system of magnetic field lines above the photosphere are drawn.
Title: Main phases of active region's magnetic field development
Authors: Bumba, V.
Bibcode: 1986CoSka..15...49B
Altcode:
Three main evolutionary stages of a magnetic local field development
are characterized.
Title: Solar local magnetic fields and their relations to the
background fields
Authors: Bumba, V.
Bibcode: 1986CoSka..15..495B
Altcode:
Generalization of some of the author's recent results concerning the
close mutual relation of solar magnetic background and local fields is
presented. Dependence of local field formations on sector structure and
through it on Magnetic Active Longitudes, influence of differential
rotation and convectional elements and the role of local fields in
the background field dynamics are described.
Title: Project INTERSHOCK - investigation of the fine structure of
shock waves in cosmic plasma - aims, problems, methods.
Authors: Galeev, A. A.; Bumba, V.; Vajsberg, O. L.; Fischer, S.;
Zastenker, G. N.
Bibcode: 1986KosIs..24..147G
Altcode:
No abstract at ADS
Title: Characteristic Patterns of Solar Magnetic Fields Around the
Positions of Flares with Enhanced Helium-3 Abundance
Authors: Bumba, V.
Bibcode: 1985BAICz..36..177B
Altcode:
The positions of solar flares identified in the He3-rich Solar Flares
Catalog of Slivka (1982) were compared with magnetic field patterns for
selected areas of the solar disk during the period 1968-1978. A high
concentration of He3 solar flares was found in magnetically active
longitudes; practically all of the flare events occurred in or near
a well-defined magnetic field boundary surrounded by a field of the
opposite polarity. The patterns of the magnetic field lines in the
magnetically active longitudes are shown in synoptic charts. It is
concluded that the geometry of the magnetic field may contribute to
the enrichment of flare particles by H3.
Title: Scientific objectives of the Intershock project.
Authors: Bumba, V.; Galeev, A.
Bibcode: 1985inpr.conf...12B
Altcode:
No abstract at ADS
Title: Processes Observable in the Photosphere During the Formation
of an Active Region. 3. Development of an Active Region at the Edge
of an Older Bipolar Magnetic Field
Authors: Bumba, V.; Suda, J.
Bibcode: 1984BAICz..35..224B
Altcode:
Processes visible during several impulses of new sunspot formations
at the periphery of an older large background magnetic field body,
in which one rotation earlier the large June-July 1974 proton-flare
region developed, are discussed. The coalescence of separate nuclei
into the future umbra and the counter-clockwise rotation of the whole
leading region, the change of the rotational sense during its further
development, as well as the non-simultaneous development of individual
parts of the active region are underlined.
Title: Processes observable in the photosphere during the formation
of an active region. II - Development of a usual active region;
growth of a SPOT penumbra
Authors: Bumba, V.; Suda, J.
Bibcode: 1984BAICz..35...28B
Altcode:
All processes visible during the development of the magnetic field,
sunspots and chromospheric structures in the usual active region of
August 1974 are studied. The connection of the active region with
the dynamics of the background field is discussed. The formation of a
"centre of magnetic activity" is demonstrated on magnetic charts as
well as in photospheric and chromospheric details. The regularities
in the active region's magnetic field topology and dynamics, and their
relations to the sunspot group development and formation of individual
sunspots are shown. The process of formation of a penumbra is described.
Title: L. Perek, 65th birthday.
Authors: Bumba, V.
Bibcode: 1984Rise...65..148B
Altcode:
No abstract at ADS
Title: Solar and stellar activities.
Authors: Bumba, V.
Bibcode: 1984StCeF..36..438B
Altcode:
Following recent observations of solar-like activity in red dwarf
stars, similar processes in solar and stellar atmospheres due to
the action of the magnetic fields are analyzed. The correlation
between the stellar atmosphere and the evolution and distribution
of the magnetic field is discussed, as well as the activity of the
photosphere, chromosphere and corona as connected with magnetic flux
in the stellar photosphere. Finally, the dynamics of the solar local
magnetic fields and the dynamo theory are also studied.
Title: Processes Observable in the Photosphere During the Formation
of an Active Region. 1. Development of a Very Small, Secondary
Active Region
Authors: Bumba, V.; Suda, J.
Bibcode: 1983BAICz..34..349B
Altcode:
Observations made with the Ondrejov radiospectrograph in the frequency
band 70-810 MHz on July 4, 1974 are used to investigate processes
accompanying the formation of a very small secondary active region. The
formation of this region is examined in relation to the development of a
new local magnetic field on the background field through restructuring
and dissipation and in relation to the evolution of a small bipolar
sunspot group. Magnetic flux values are estimated, and attention is
given to the morphology of the transformation of small sunspots and
to two modes of small-sunspot disintegration.
Title: How Does the Magnetic Field of an Usual Active Region Develop?
Authors: Bumba, V.
Bibcode: 1983BAICz..34..219B
Altcode:
The existence of a regular pattern of development in a single solar
active region's magnetic field, at least in some of its evolutionary
stages, and the pattern's dependence on the heliographic position
or on the phase of the solar activity cycle is investigated using
about 36 sets of 'qualitative' maps of the longitudinal field
distribution. Evidence of the influence of solar differential
rotation on the shape of the magnetic field and of other dynamical
forces arising from the flow of photospheric matter around the active
region is obtained. It is shown that magnetic lines of force in the
active region's 'center' form a subsystem which is lower than and
perpendicular to the main system of magnetic lines of force joining
the leading and following main spots.
Title: The Problem of Field Geometry in Sunspots
Authors: Bumba, V.; Suda, J.
Bibcode: 1983BAICz..34..155B
Altcode:
A comparison is conducted of the results of older spectroscopic magnetic
field and velocity field observations in regular sunspots with the
results obtained from white-light and monochromatic photographs of
sunspots in the form of three schemes of magnetic field lines of force,
velocity vectors and fine structure fibril distribution. From these
schemes, the horizontal as well as the vertical scales of which are not
distorted, the good agreement of the magnetic field distribution in the
penumbra with motion of the photospheric and chromospheric penumbral
matter, their depths and heights are seen. The difference between
the umbral and penumbral field topology and physical conditions, as
well as the uncertainty of the position of bright penumbral fibrils
in relation to the magnetic field and radial motion distribution
is also obtained. The possible conclusions of this comparison are
briefly discussed.
Title: Observable physical effects during new solar active regions
formations
Authors: Bumba, V.
Bibcode: 1983AN....304....7B
Altcode:
The present paper is an attempt to demonstrate the importance of
detailed observations for the theory of solar local magnetic field
generation. Mutual relations of solar background magnetic fields and
new active region formations are described. The influence of various
factors, dependent on as well as independent of the cycle of solar
activity and the dynamics of background fields, is considered. All
forces and effects whose action can be derived from systematic
observations of magnetic field distribution and high resolution
photospheric photographs of all stages of active regions development are
discussed. The influence of convection, of the reaction on field lines
penetration, of various magnetic forces, of differential rotation,
and of hydrodynamical forces is demonstrated. The importance of a
'center of magnetic activity', a magnetic subsystem orthogonal to the
main system of active region's field as a source of new magnetic flux,
is underlined. The necessity of a new approach to the problem of local
magnetic field generation is stated.
Title: Proper motions observed in active regions.
Authors: Bumba, V.
Bibcode: 1983PDHO....5...47B
Altcode: 1984PDHO....5...47B
The author summarizes the results obtained from the observations of
proper motions visible during the growth of local magnetic fields of
active regions and during the formation and further development of their
sunspot groups. The low efficiency of magnetic forces during the studied
processes and, in contrast, the importance of hydrodynamic forces is
demonstrated. The feedback action of the moving photosphere on the shape
of magnetic field distribution and on the sunspot forms is shown too.
Title: Development of Sunspots in the Colliding Magnetic Fields of
the June - July 1974 Proton-Flare Group
Authors: Bumba, V.; Suda, J.
Bibcode: 1983BAICz..34...29B
Altcode:
Results are presented of a study on the development of sunspots in the
colliding magnetic fields of two large active regions that together
form one complex proton-flare sunspot group. Not only morphological
changes in two types of sunspot light bridges but also the formation
of new sunspots in two main and one secondary 'center of gravity'
are shown. These are in good agreement with the 'magnetic centers'
and, in particular, with the dynamical consequences of the motions
and collisions of different umbrae of like as well as unlike polarities.
Title: Magnetic Field Development in an Isolated Active Region
(McMath No. 13 736)
Authors: Bumba, V.; Klvaňa, M.; Tomášek, P.
Bibcode: 1982BAICz..33..321B
Altcode:
The relation of the magnetic field development in an isolated
active region to the dynamics of the background magnetic field is
investigated. Only the magnetic field longitudinal component is used to
estimate the growth of the magnetic flux values for both polarities. The
magnetic field is found to slowly dissipate and enlarge its area during
the five rotations after the first appearance of the field. The rate of
field expansion in heliographic longitude and latitude is determined
to approximate 10 degrees per rotation. It is suggested that the
formation of a secondary active region during the postmaximum phase
of the development of the main active region is a natural phase in the
evolution of the main active region's magnetic field. The active region
is considered to be the final product of a secondary active longitude,
and after this source has disappeared the system of magnetic fields
dissipates in its own way.
Title: June-July 1974 Proton-Flare Region. IV. The Dynamics of the
Local Magnetic Field Evolution during the Proton-Flare Events Rotation
Authors: Bumba, V.
Bibcode: 1982BAICz..33..281B
Altcode:
The dynamics of the day to day evolution of the June-July 1974
proton-flare region's local magnetic field, composed originally of at
least two individual local fields, are analyzed, and the development
of the magnetic centers of activity of the proton-flare local magnetic
field is investigated. Results show that the development of the new
magnetic fluxes can be related to two main and at least one secondary
center of activity. It is indicated that one of the main reasons for the
changes of the observed field topology is the tendency of the complex
magnetic field to form one simple bipolar field, properly inclined
toward the equator. During these changes of the field topology, the
positive field of the eastern region extended toward the west to join
the same polarity field of the western region and became the main
leading field. The western negative polarity field shifted towards
the east to join the eastern field of like polarity which took over
the role of the main following field.
Title: June-July 1974 Proton-Flare Region. III. The Geomagnetic
Activity During the Declining Phase of the Complex Process
Authors: Bumba, V.
Bibcode: 1982BAICz..33..215B
Altcode:
Characteristics of the solar wind emanating from the region of
the solar atmosphere in which the formation of the June-July 1974
proton-flare region took place are investigated. It is shown that the
daily geomagnetic character figures C 9 reach their maximum when the
rapid disintegration and disappearance of the large-scale characteristic
magnetic field patterns occur and when there is a sudden cessation
of sunspot, flare, and coronal activity. This solar wind enhancement
is taken as one of the last observable manifestations of the entire
complex process.
Title: June - July 1974 Proton-Flare Region II. Regularities in the
Magnetic Field Area and Related Sunspot and Flare-Activity Development
Authors: Bumba, V.; Hejna, L.; Yen, Le Bach
Bibcode: 1982BAICz..33..160B
Altcode:
No abstract at ADS
Title: Solar Active Region SD 55/1975 in the Frame of the Background
Magnetic Field Development
Authors: Bumba, V.; Klvana, M.; Pflug, K.
Bibcode: 1982BAICz..33...36B
Altcode:
The evolution of the background magnetic field pattern is
described. The complex needed only one or two rotations to reach its
maximum evolutionary state and its whole duration was about 10 or 12
rotations. The studied active region appears during the early stages of
a new impulse of activity, whose development is described along with
that of the green coronal emission of which the complex of activity
forms the center of gravity. Low resolution magnetic maps are used to
describe the development of the complex of activity and high resolution
maps are used to compare characteristic evolutionary features of the
active region with photospheric and chromospheric development. It is
concluded that the active region represents only a small part of a
more general evolutionary process of the magnetic field.
Title: Development of Solar Energetic Particle Sources Within the
Background Magnetic Fields
Authors: Bumba, V.
Bibcode: 1982SSRv...32..229B
Altcode:
The greatest coronal and interplanetary disturbances are considered
consequences of complex processes accompanying development of
large-flare regions. Such regions not only possess a specific
magnetic field configuration, but their magnetic topology develops
following certain rules within the frame of slowly changing large-scale
distribution of the background magnetic field patterns as a result of
the mutual influences of new magnetic flux appearance as well as old
field weakening and dissipation. In this paper we try to demonstrate
the individual phases of the large-scale long lasting magnetic field
pattern formation with their morphological characteristics and magnetic
field configurations. The time scale of the whole process is shown,
and the possible reasons of such development are discussed. The proton
flare regions of August 1972 and July 1974 are used as examples of
the successive magnetic field complication and strengthening, the
result of which is the appearance of still more complicated magnetic
and velocity fields that produces proton flares and then the fast
disintegration of the whole magnetic situation occupying more than
one half of the visible solar surface following the occurrence of the
proton flares. The consequences which may be used for the proton flare
prediction are discussed.
Title: Solar Activity
Authors: Bumba, V.
Bibcode: 1982IAUTA..18...55B
Altcode: 1982IAUT...18...55B
No abstract at ADS
Title: Significance of observations for modeling of sunspots and
their groups development
Authors: Bumba, V.
Bibcode: 1982HvaOB...6..101B
Altcode:
The model of magnetic lines of force spread in a regular sunspot
contradicting the observable distribution of bright penumbral fibrils
in regular spots close to the solar limb is discussed as well as the
dynamical effects seen in the photosphere due to the sunspots motion
and collision.
Title: Solar Magnetic Fields and Activity
Authors: Bumba, V.
Bibcode: 1982coas.conf...81B
Altcode: 1982cia..conf...81B
No abstract at ADS
Title: Links of Hα-Emission Features with the Underlying Elements
of Sunspot Fine Structures in Some Flares
Authors: Bumba, V.; Suda, J.; Ishkov, V. N.
Bibcode: 1981BAICz..32..286B
Altcode:
The positions of individual flare-emission features penetrating the
umbrae of sunspots are compared with the underlying elements of these
umbrae. Five flares in three large and complex active regions are
investigated. The results obtained demonstrate that the flare emission
observed in the wings of the hydrogen H(alpha)-line correlates well
with the photospheric-like sunspot light-bridges and gulfs of umbrae and
that it mostly avoids the darkest parts of umbrae, the field intensity
of which is usually greater than 200 mT.
Title: June-July 1974 Proton-Flare Region. I. Individual Stages of
Its Background and Local Magnetic Field Development
Authors: Bumba, V.; Hejna, L.
Bibcode: 1981BAICz..32..349B
Altcode:
Evolutionary characteristics of the large-scale magnetic field pattern
producing the June-July 1974 proton flare region are described. The
region's space and time relation to the intersection of two different
magnetically active longitudes is estimated, and its individual
development stages are demonstrated. The process of successive
complication of local magnetic field producing the proton-flare region
and its growth of complexity in frame of the background magnetic field
continuous redistribution are studied. The development of the June-July
1974 magnetic situation and that of the August 1972 proton-flare region
are compared, finding many similarities although the events occurred
at distinct stages of the solar cycle with different situations of
activity density and with different latitudes.
Title: Beginning Stages of Local Magnetic Field Formation
Authors: Bumba, V.
Bibcode: 1981BAICz..32..129B
Altcode:
Based on a study of the initial stages of local magnetic field
formation, the appearance of a new magnetic flux in the photosphere
is studied. This magnetic flux is found to occur both under the
influence of different modes of convective motion as well as under
the action of Paleomagnetic fields. Waldmeier's Heliographic Maps of
the Photosphere and Mt. Wilson Observatory daily magnetic maps were
used in the analysis. Observed regularities could not be explained by a
model of magnetic flux tubes emerging on the photospheric surface. This
model can not account for the practically simultaneous development of
separate active regions, belonging to different solar hemispheres and
different cycles of solar activity in one, relatively narrow, 'unipolar'
sector of the background field. It is also difficult to explain the
different roles and velocities of negative and positive polarities
during the formation of new magnetic fields. The importance of velocity
measurements and maps for solving the observed phenomenon is stressed.
Title: Some Peculiarities in the Development of the Large August
1972 Sunspot Group
Authors: Bumba, V.; Hejna, L.
Bibcode: 1980BAICz..31..257B
Altcode:
On the basis of a large series of good quality sunspot photographs and
with the aid of daily Mt. Wilson magnetograms the individual phases in
the August 1972 proton-flare sunspot grou5 development are found and
their relation to the changes of magnetic field topology estimated. A
very detailed description of two types of sunspot light-bridge evolution
and their dependence on the magnetic field polarity distribution is
given. A brief summary of the investigation of the chromospheric fine
structure morphology determination by the underlying photospheric as
well as magnetic field details in the group is presented. Finally, some
development peculiarities, especially the exceptional role of features
with the positive polarity fields embraced by the negative polarity
fields in the formation of strong field gradients are compared with
the evolution of some peculiarities in the July 1974 proton-flare group.
Title: August 1972 Proton-flare Region and Different Phases of Its
Background Magnetic Field Development
Authors: Bumba, V.
Bibcode: 1980BAICz..31..351B
Altcode:
Magnetic synoptic charts and daily maps are used to examine the
individual phases and separate impulses of the background magnetic field
evolution accompanying the development of the August 1972 proton-flare
region. The fast disintegration and dissipation of the magnetic field
of the main proton-flare region during the few rotations following
the occurrence of the proton-flare event is emphasized.
Title: Initial phase of the development of the magnetic field of an
active region in the photosphere
Authors: Bumba, V.; Tomasek, P.
Bibcode: 1980tpmb.meet...35B
Altcode:
The initial phases of the development of magnetic fields in new
active regions were studied on the basis of daily magnetic maps from
Mt. Wilson Observatory and magnetic charts of individual active regions
obtained at the Ondrejov Observatory. It is found that the formation
of the magnetic flux of new active regions appears to be a part of
the process of background magnetic field development and is determined
by the supergranular network. The formation of a new active region is
characterized by the relationship between a new field and the 'unipolar'
region of an old field; the temporal succession in the appearance of
the following and leading portions of the new region; the important
role of the negative polarity field; the successive development of
fluxes of individual polarities; the identity of the basic focus of
magnetic field development with the center of developing sunspot groups;
and the existence of secondary centers of magnetic field development.
Title: 17th General Assembly of the IAU and the actual aims of
astronomy.
Authors: Bumba, V.; Kresák, L'.; Kríz, S.; Vanýsek, V.
Bibcode: 1980Vesmi..59....1B
Altcode:
No abstract at ADS
Title: Internal Structure of Sunspot Umbrae
Authors: Bumba, V.; Suda, J.
Bibcode: 1980BAICz..31..101B
Altcode:
The paper reports high-resolution photographic investigations of the
structural details in sunspot umbrae which belong to spots with various
magnetic field intensity values in different evolutionary phases, and
occurring in groups with a distinct magnetic field and morphological
topology. It was found that each sunspot umbrae, regardless of size,
magnetic field intensity, darkness, form, age or presence of a penumbra,
has an identical internal morphological structure formed of a dark
network of cellular elements, the center of each being filled in by a
bright grain. Constructed structural maps, representing the positions
of the bright central parts of the cellular elements, are completely
identical for photospheric and umbral granular fields. In addition,
the lifetime of the individual umbral cells is found to be between
10-30 minutes in most cases, while the fundamental physical importance
of the dark intergranular space in the photosphere is re-emphasized
in this study.
Title: Problems of solar activity
Authors: Bumba, V.; Klechek, I.; Obridko, V. I.
Bibcode: 1979psa..conf.....B
Altcode:
No abstract at ADS
Title: The Astronomical Institute of the Czechoslovak Academy of
Sciences.
Authors: Bumba, V.
Bibcode: 1979aica.book.....B
Altcode:
No abstract at ADS
Title: Large-scale solar magnetic fields.
Authors: Bumba, V.
Bibcode: 1979psa..conf...50B
Altcode:
No abstract at ADS
Title: Book reviews
Authors: Roberts, Paul H.; Scholer, Manfred; de Jager, C.; Ceplecha,
Zdeněk; Grewing, M.; Kresák, L.; Bumba, Václav; Pottasch, S. R.;
Sehnal, L.; Pagel, Bernard; Reijnen, G. C. M.; Ness, Norman F.;
de Jager, Cornelis
Bibcode: 1978SSRv...22..213R
Altcode:
No abstract at ADS
Title: Astronomical Institute of the Czechoslovak Academy of Sciences.
Authors: Bumba, V.
Bibcode: 1978Rise...59....1B
Altcode:
No abstract at ADS
Title: Solar double telescope at the Hvar Observatory
Authors: Ambroz, P.; Bumba, V.; Havlicek, K.; Ptacek, J.; Suda, J.
Bibcode: 1977HvaOB...1...15A
Altcode:
No abstract at ADS
Title: Individual phases in the August 1972 proton-flare region
development.
Authors: Bumba, V.; Hejna, L.
Bibcode: 1977PDHO....3..111B
Altcode:
No abstract at ADS
Title: The main characteristics of magnetic field developments
responsible for the formation of the July 1974 proton-flare region.
Authors: Bumba, V.; Hejna, L.; Bach Yen, Le
Bibcode: 1977PDHO....3..161B
Altcode:
No abstract at ADS
Title: Results of investigations on solar physics within the frame
of the Intercosmos programs.
Authors: Martini, L.; Jakimiec, J.; Tindo, I. P.; Bumba, V.; Dezsö, L.
Bibcode: 1977PDHO....3..305M
Altcode: 1977issp.conf..305M
No abstract at ADS
Title: On the origin of active regions. Magnetographic observations.
Authors: Bumba, V.
Bibcode: 1977IzKry..56..188B
Altcode:
In this survey of studies concerning the origin of active regions,
emphasis is placed on the relations among the distribution of
magnetic fields, the origin of active regions, and the large-scale
distribution of background magnetic and velocity fields in the solar
atmosphere. The development of active regions is discussed with
reference to supergranulation, and the development of sun spots and
sun spot groups is considered with attention to magnetic and velocity
fields. Maps of magnetographic observations are presented, and the
implications of the data for the determination of solar phenomena
interrelationships are examined.
Title: A Note on Recurrences in the Magnetic Field Distribution
during the Present Cycle of Solar Activity
Authors: Bumba, V.
Bibcode: 1976BAICz..27...74B
Altcode:
Some results are presented for a preliminary analysis of synoptic
magnetic charts obtained at Mt. Wilson Observatory during the present
solar-activity cycle. Practically no changes in the behavior of the
magnetic-field distribution are observed in the present cycle relative
to the preceding one. It is found that even the roles of positive and
negative polarities seem unchanged, although their functions as leading
and trailing polarities have been exchanged. The importance of the
two basic recurrences or sequences in the large-scale magnetic-field
distribution, with respective periods of 27 days and 28-29 days,
is emphasized. The existence of latitudinal shifts or 'oscillations'
in solar activity is noted.
Title: Conditions for Solar Observations at the Ondřejov Observatory
Authors: Bumba, V.; Hrebik, F.; Suda, J.
Bibcode: 1976BAICz..27..217B
Altcode:
An attempt to demonstrate the suitability of the Ondrejov Observatory
for high-quality and high-resolution observations of solar features
is made, drawing on all systematic solar observations undertaken
at the site since 1948. The climate of Ondrejov, as well as the
observational conditions over the years and during different months,
are discussed. The changes of solar seeing in the course of the day and
the intervals of best seeing conditions are shown. Some high-quality
photographs of the photosphere are presented as an example of the
usefulness of the observational material for obtaining new aspects of
solar active regions.
Title: Horizontal Instrument for Solar Magnetic and Velocity Field
Measurements
Authors: Bumba, V.; Klvana, M.; Macak, P.
Bibcode: 1976BAICz..27..257B
Altcode:
A brief description of the optical system and technical equipment of
a horizontal instrument used for solar magnetic- and velocity-field
measurements is given. Methods of photographic as well as photoelectric
determination of certain components of both fields are described. Some
examples of the instrument's performance are given.
Title: Large-scale magnetic structures and the longitudinal
distribution of the green coronal emission
Authors: Bumba, V.; Sýkora, J.
Bibcode: 1976CoSka...6..231B
Altcode:
No abstract at ADS
Title: Basic mechanisms of solar activity, proceedings from IAU
Symposium no. 71 held in Prague, Czechoslovakia, 25-29 August 1975.
Authors: Bumba, Vaclav; Kleczek, Josip
Bibcode: 1976IAUS...71.....B
Altcode: 1976QB524.B37......
No abstract at ADS
Title: Some characteristics of the magnetic field and photospheric
structure development in the August 1972 proton-flare region
Authors: Ambrož, P.; Bumba, V.; Suda, J.
Bibcode: 1976CoSka...6...15A
Altcode:
No abstract at ADS
Title: Some characteristics of the magnetic field and photospheric
structure development in the August 1972 proton-flare region.
Authors: Ambroz, P.; Bumba, V.; Suda, J.
Bibcode: 1976str..book...15A
Altcode:
No abstract at ADS
Title: The initial phases of sunspot group development.
Authors: Bumba, V.; Klvana, M.; Suda, J.
Bibcode: 1976veao.conf...59B
Altcode:
No abstract at ADS
Title: Light-bridges and the distribution of the magnetic field
polarity in sunspot groups.
Authors: Bumba, V.; Klvana, M.; Suda, J.
Bibcode: 1976fsp..conf...49B
Altcode:
No abstract at ADS
Title: Large-scale magnetic structures and the longitudinal
distribution of the green coronal emission.
Authors: Bumba, V.; Sykora, J.
Bibcode: 1976str..book..231B
Altcode:
No abstract at ADS
Title: Relations between the Solar and Interplanetary Magnetic
Field Distributions
Authors: Bumba, V.
Bibcode: 1976BAICz..27..153B
Altcode:
Correlations of the negative and positive polarity sectors of the
interplanetary magnetic field (IMF) with the main bodies of the
negative and positive supergiant structures of the solar magnetic
field are pointed out. When the IMF is bipolar, the negative-positive
sector boundary lies close to the region of high activity. The shift of
sector boundaries in heliographic longitude, if examined in successive
rotations, is parallel to that of the solar magnetic field rows and
streams in the equatorial strips of solar synoptic magnetic charts
mounted successively. This means that the synodic rotation of the sector
boundaries is close to 27 days. At the same time, the centers of gravity
of successive interplanetary field sectors are shifted to the east
with synodic rotation close to 28-29 days. Both main types of shifts
have been found in the solar background magnetic field distribution.
Title: Dynamics of sunspot development.
Authors: Bumba, V.
Bibcode: 1976fsp..conf..123B
Altcode:
No abstract at ADS
Title: Large-Scale Solar Magnetic Fields
Authors: Bumba, V.
Bibcode: 1976IAUS...71...47B
Altcode:
No abstract at ADS
Title: Investigation of solar short-wavelength radiation and solar
activity
Authors: Bishoff, K.; Bumba, V.; Vainshtein, L. A.; Valnicek, B.;
Gerlen, O.; Gogosheva, Ts.; Grineva, Iu. I.; Dezhe, L.; Dertianosh,
D.; Zhitnik, I. A.
Bibcode: 1976ip...book..102B
Altcode:
Studies of solar radiation in the range from 1500 A to 1 A (X-rays and
XUV), from satellites outside the earth's atmosphere, are reviewed
on the basis of the Intercosmos 1969-1974 program (Intercosmos-1,
Intercosmos-4, Intercosmos-7, Intercosmos-11, Vertikal'-1,
Vertikal'-2). X-ray and UV emissions of the quiet sun, solar X-ray
bursts, forecasts of solar X-ray and UV activity in relation to solar
bursts, and penetration of upper layers of the earth's atmosphere by
solar UV radiation are discussed. Correlations between satellite solar
X-ray and XUV data, and earth-based optical and radio-frequency data,
on solar activity are studied.
Title: Scientific cooperation of solar physicists in socialistic
countries
Authors: Bumba, V.
Bibcode: 1975cesra...5...98B
Altcode:
No abstract at ADS
Title: Concerning some actual problems in the observational solar
research.
Authors: Bumba, V.
Bibcode: 1975POBeo..20...35B
Altcode:
No abstract at ADS
Title: Scientific cooperation of solar physicists in socialistic
countries.
Authors: Bumba, V.
Bibcode: 1975MmArc.105...98B
Altcode:
No abstract at ADS
Title: Granular-like pattern in sunspot umbrae.
Authors: Bumba, V.; Hejna, L.; Suda, J.
Bibcode: 1975BAICz..26..315B
Altcode:
No abstract at ADS
Title: Large-Scale Magnetic Structures Responsible for Coronal
Disturbances (presented by V. Bumba)
Authors: Bumba, V.; Sýkora, J.
Bibcode: 1974IAUS...57...73B
Altcode:
No abstract at ADS
Title: The Relation Between Chromospheric and Photospheric Structures
in Sunspot Groups
Authors: Bumba, V.; Ambroz, P.
Bibcode: 1974IAUS...56..183B
Altcode:
No abstract at ADS
Title: Photospheric Convective Network as a Determining Factor in
Sun-spot and Group Development and Stabilization
Authors: Bumba, V.; Ranzinger, P.; Suda, J.
Bibcode: 1973BAICz..24...22B
Altcode:
No abstract at ADS
Title: Particle emitting flares and the large-scale distribution of
solar magnetic fields and green corona.
Authors: Bumba, V.; Sýkora, J.
Bibcode: 1973spre.conf..803B
Altcode: 1973spre....2..803B
No abstract at ADS
Title: The sun as a star.
Authors: Bumba, V.
Bibcode: 1973saa..conf....9B
Altcode:
No abstract at ADS
Title: The dominating role of convection in the development of solar
activity centers.
Authors: Bumba, V.; Suda, Ya.
Bibcode: 1973SZFiz...3..222B
Altcode:
No abstract at ADS
Title: Typical Characteristics of the Active Region With Proton
Flare Behind the Limb (2 November 1969) and Accompanying Effects
Authors: Bumba, V.; Krivsky, L.; Tlamicha, A.; Sykora, J.; Halenka,
J.; Lastovicka, J.; Triska, P.; Pinter, S.
Bibcode: 1972spen.conf...19B
Altcode:
No abstract at ADS
Title: Large-Scale Magnetic Fields and Activity Patterns on the Sun
Authors: Bumba, V.
Bibcode: 1972ASSL...29...21B
Altcode: 1972sun..conf...21B
No abstract at ADS
Title: The connection of large-scale distribution of solar magnetic
fields and coronal features with large flares and the solar wind.
Authors: Bumba, V.; Sykora, J.
Bibcode: 1972SZFiz...3..231B
Altcode:
No abstract at ADS
Title: Large-Scale Negative Polarity Magnetic Fields on the Sun and
Particle-Emitting Flares
Authors: Bumba, V.
Bibcode: 1972NASSP.308...31B
Altcode: 1972sowi.conf...31B
No abstract at ADS
Title: Solar Large-Scale Positive Polarity Magnetic Fields and
Geomagnetic Disturbances
Authors: Bumba, V.
Bibcode: 1972NASSP.308..151B
Altcode: 1972sowi.conf..151B
No abstract at ADS
Title: Development and spatial structure of proton flares near the
limb and coronal phenomena. IV. Proton flare on November 2, 1969
and its active region
Authors: Bumba, V.; Křivský, L.; Sýkora, J.
Bibcode: 1972BAICz..23...85B
Altcode:
No abstract at ADS
Title: Large-scale magnetic fields and activity patterns on the sun.
Authors: Bumba, V.
Bibcode: 1972sstp.conf...21B
Altcode:
No abstract at ADS
Title: Opposite Polarities in the Development of Some Regularities
in the Distribution of Large-Scale Magnetic Fields
Authors: Ambroz, P.; Bumba, V.; Howard, R.; Sýkora, J.
Bibcode: 1971IAUS...43..696A
Altcode:
No abstract at ADS
Title: Some Remarks on the Statics and Dynamics of Magnetic Field
Structure Development in Active Regions
Authors: Bumba, V.; Suda, J.
Bibcode: 1971IAUS...43..201B
Altcode:
No abstract at ADS
Title: Large Scale Regularities in Solar Magnetic Field Distribution
and Occurence of Large Flares
Authors: Bumba, V.
Bibcode: 1971PDHO....2...13B
Altcode:
No abstract at ADS
Title: Role of the Convective Network in the Development of Sunspots,
Sunspot Groups and Flares
Authors: Bumba, V.; Suda, J.; Ranzinger, P.
Bibcode: 1971PDHO....2...21B
Altcode:
No abstract at ADS
Title: Concerning the Formation of Giant Regular Structures in the
Solar Atmosphere
Authors: Bumba, V.
Bibcode: 1970SoPh...14...80B
Altcode:
Using the Mt. Wilson magnetic synoptic charts from the recent
solar activity cycles the dynamics of the formation of giant regular
structures formed in the plus (leading) polarity of older more extended
magnetic fields are studied. Although their diameters are about one
order greater than those of supergranules, the processes of their
development go analogously to those of supergranulation and granulation.
Title: Solar Activity and Recurrences in Magnetic-Field Distribution
Authors: Bumba, V.; Howard, R.
Bibcode: 1969SoPh....7...28B
Altcode:
A study of the Mount Wilson magnetic-field synoptic chart material
divided into latitude zones for the interval 1959-67, and a comparison
of the data with sunspot groups have provided a better understanding
of the structure of the background-field pattern and its relation to
activity. The interaction of old and new fields within the pattern
seems to result in long-lived sections of alternating polarity in both
hemispheres. We postulate subsurface sources with rotation periods of
about 27 days which produce active regions over a longitude zone of
some tens of degrees. There is a tendency for the background-field
features with strong fields to resist to some extent the shearing
effects of differential rotation. A prediction is made concerning the
nature of the interplanetary magnetic field above the ecliptic.
Title: Relation of 1420 MHz radio emission to the distribution of
photospheric magnetic fields, coronal emission and filaments
Authors: Bumba, V.; Kleczek, J.; Olmr, J.; Rů ŽiČková-Topolová, B.
Bibcode: 1969BAICz..20...67B
Altcode:
No abstract at ADS
Title: Some regularities in the distribution of large-scale magnetic
fields on the Sun
Authors: Bumba, V.; Howard, R.; Kopecký, M.; Kuklin, G. V.
Bibcode: 1969BAICz..20...18B
Altcode:
No abstract at ADS
Title: On the solar sources of recurrent geophysical effects
Authors: Bumba, V.; Howard, R.
Bibcode: 1969BAICz..20...61B
Altcode:
No abstract at ADS
Title: Magnetic fields, green corona and filaments in high solar
latitudes
Authors: Bumba, V.; Růžičková-Topolová, B.
Bibcode: 1969BAICz..20...63B
Altcode:
No abstract at ADS
Title: On long-term forecasts of solar activity
Authors: Bumba, V.; Howard, R.
Bibcode: 1969sfsr.conf..387B
Altcode:
No abstract at ADS
Title: Variability of solar calcium emission during one solar rotation
Authors: Bumba, V.; Růžičková-Topolová, B.
Bibcode: 1969csph.conf...93B
Altcode:
No abstract at ADS
Title: Atlas of solar magnetic fields.
Authors: Howard, R.; Bumba, V.; Smith, S. F.
Bibcode: 1969asmf.book.....H
Altcode:
No abstract at ADS
Title: On forecasts of interplanetary and geophysical conditions
Authors: Howard, R.; Bumba, V.
Bibcode: 1969sfsr.conf..397H
Altcode:
No abstract at ADS
Title: `Bartels' active longitudes', sector boundaries and flare
activity
Authors: Bumba, V.; Obridko, V. N.
Bibcode: 1969SoPh....6..104B
Altcode:
The flare activity and especially the proton-flare activity is
concentrated in the zones of `Bartels' active longitudes' and in the
neighbourhood closest to the sector boundaries of the interplanetary
magnetic field. This concentration seems to be greater if the importance
of the event increases.
Title: Flare Activity and Spotgroup Development
Authors: Bumba, V.; Krivský, L.; Martres, M. J.; Soru-Iscovici, I.
Bibcode: 1968IAUS...35..311B
Altcode:
No abstract at ADS
Title: Correlation Between CA Plages and Longitudinal Magnetic Fields
of the Cssar Active Regions
Authors: Bumba, V.; Godoli, G.
Bibcode: 1968IAUS...35..338B
Altcode:
No abstract at ADS
Title: The interplanetary sector structure and solar radio emission
Authors: Krüger, A.; Bumba, V.; Howard, R.; Kleczek, J.
Bibcode: 1968BAICz..19..180K
Altcode:
No abstract at ADS
Title: Patterns of Active Region Magnetic Field Development
Authors: Bumba, V.; Howard, R.; Martres, M. J.; Soru-Iscovici, I.
Bibcode: 1968IAUS...35...13B
Altcode:
No abstract at ADS
Title: Last Phases of Development of Active Regions
Authors: Bumba, V.; Kleczek, J.; Olmr, J.; Ruzicková-Topolova, B.;
Sýkora, J.
Bibcode: 1968IAUS...35...64B
Altcode:
No abstract at ADS
Title: Magnetic Fields in Small and Young Sunspots
Authors: Bumba, V.
Bibcode: 1967SoPh....1..371B
Altcode:
Preliminary results of magnetic field measurements in small sunspots
from spectrograms obtained with the aid of the McMath Solar Telescope
at the Kitt Peak National Observatory are presented. The measured
intensities are greater than or equal to about 1200 Gauss. Furthermore,
a broadening of the FeI line λ6302.508 Å was found in some places
of intergranular space. The importance of intergranular space as a
possible potential earliest stage of sunspot development is mentioned.
Title: Variability of the Integrated Solar K Line Emission
Authors: Bumba, V.; Růžičková-Topolová, B.
Bibcode: 1967SoPh....1..216B
Altcode:
The preliminary results presented in this note seem to demonstrate
the facts that the sun observed as a star in the light of the K and
H lines is variable, and that this variability is closely related to
that of the magnetic field intensity, or to the distribution of magnetic
fields, and hence to the distribution of calcium plages or photospheric
faculae in the solar atmosphere. This variability will not so much be
related to the variation of Wolf's relative sunspot numbers or to the
variation of the sunspot area. The applicability of the obtained
results for the examination of the late-type stars seems to be evident.
Title: The Sun as a Magnetic Star
Authors: Bumba, V.; Howard, Robert; Smith, Sara F.
Bibcode: 1967mrs..conf..131B
Altcode:
No abstract at ADS
Title: Radial motions in small and young sunspots
Authors: Bumba, V.
Bibcode: 1967BAICz..18..238B
Altcode:
No abstract at ADS
Title: Atlas of solar magnetic fields
Authors: Howard, Robert; Bumba, V.; Smith, Sara F.
Bibcode: 1967asmf.book.....H
Altcode: 1967QB539.H65......
No abstract at ADS
Title: A Note on the Identification of "m" Regions
Authors: Bumba, V.; Howard, Robert
Bibcode: 1966ApJ...143..592B
Altcode:
No abstract at ADS
Title: Some theoretical aspects of sunspots
Authors: Bumba, V.; Kopecký, M.; Kuklin, G. V.
Bibcode: 1966BAICz..17...57B
Altcode:
No abstract at ADS
Title: Solar Magnetic Fields
Authors: Bumba, V.; Howard, Robert
Bibcode: 1965Sci...149.1331B
Altcode:
No abstract at ADS
Title: On the Development of Solar Flares Within the Calcium Network.
Authors: Bumba, V.; Howard, Robert
Bibcode: 1965ApJ...142..796B
Altcode:
No abstract at ADS
Title: Large-Scale Distribution of Solar Magnetic Fields.
Authors: Bumba, V.; Howard, Robert
Bibcode: 1965ApJ...141.1502B
Altcode:
Solar magnetograms covering a period of years were used to study
the distribution of weak magnetic fields on the solar surface. The
semiregular pattern of these background fields is the result of the
expansion, weakening, and stretching by differential rotation of
magnetic fields of old active regions and their interaction with
neighboring fields, and of the continuing development of magnetic
fields of new regions within the pattern. The net result is a slowly
changing pattern of background fields which occupies at times during
the solar cycle more than 50 per cent of the surface area of the Sun,
as seen with the 23" resolution of the magnetograph. The interaction
of nearby magnetic fields takes the form of the apparent attraction of
features of the same polarity and the apparent repulsion of features of
opposite polarity. Sometimes weak magnetic features covering a large
area apparently disappear over a period of a few rotations. It is not
clear from the observations what the mechanism of this disappearance
could be. It is clear from the period near minimum that active regions
are concentrated in complexes of activity whose location and development
are clearly defined. The largest of these complexes, consisting of
many active regions, result in the formation of Unipolar Magnetic
Regions (UMR). The polar fields are discussed from the standpoint of
the poleward drift of the UMR's.
Title: A Study of the Development of Active Regions on the Sun.
Authors: Bumba, V.; Howard, Robert
Bibcode: 1965ApJ...141.1492B
Altcode:
The early development of a large number of active regions was
studied. Magnetic, photospheric, and chromospheric observations from
Mount Wilson were used. It was found that the supergranular pattern of
the solar atmosphere plays a very fundamental role in the development of
active regions. New regions form in or immediately adjacent to expanding
weak old regions that are seen as an enhanced calcium network. The
first appearance of the new calcium plage (also of sunspots) takes
place in the space between several supergranules, and the subsequent
brightening occurs between supergranules, usually filling in several
of them. In many cases it appeared that during the first day or two of
the development of the group, the magnetic fields did not show zero
net flux. Usually the direction of the development of the plage was
from following to leading The increase of magnetic flux (the initial
growth of the plage) takes place only during the first few days in the
life of a region. During this period the boundary of the filamentary
structure in Ha increases at the rate of about 200 m/sec. This evidently
represents the rapid ordering of magnetic fields around the plage.
Title: Association of Green-Line Coronal Features with Photospheric
Magnetic Fields
Authors: Bumba, V.; Howard, R.; Kleczek, J.
Bibcode: 1965PASP...77...55B
Altcode:
No abstract at ADS
Title: Some notes on sunspot fine structure
Authors: Bumba, V.
Bibcode: 1965IAUS...22..305B
Altcode:
No abstract at ADS
Title: Short note on the connections between the facular network
and sunspots
Authors: Bumba, V.
Bibcode: 1965IAUS...22..192B
Altcode:
No abstract at ADS
Title: The development of sunspot groups and the supergranular pattern
Authors: Bumba, V.; Howard, R.
Bibcode: 1964susp.conf..220B
Altcode:
No abstract at ADS
Title: Large-Scale Patterns of the Solar Magnetic Field.
Authors: Bumba, V.; Howard, Robert; Smith, Sara F.
Bibcode: 1964AJ.....69Q.535B
Altcode:
Reduction of 421 years of daily magnetograms obtained with the
magnetograph built by Dr. H. W. Babcock is in progress. The angular
resolution from these observations is 23 sec of arc. Isogauss drawings
were made from the magnetograms, and synoptic charts were drawn for
each solar rotation. It is apparent that the large-scale pattern of the
solar magnetic field is for the most part the result of the spreading
out and stretching by differential rotation of portions of the magnetic
fields of old active regions. These large-scale features persist for
many months, while the small-scale patterns which are connected with
active regions can change in a matter of days. The main direction of
motion of the migrating fields is eastward and poleward. The following
polarity in each hemisphere usually predominates in the poleward drift
of fields. The polar magnetic field measurements record il~is quantized
migration of fields (Undoubtedly, as has already been pointed out,
this drift of following polarities was responsible for the reversal
in polarity observed in the polar fields during the last maximum.) It
appears that if there is a fixed component of a general solar field
it is not apparent in these observations and would have to be less
than a few tenths of a gauss. Judging from the distribution of the
large-scale magnetic fields, one would observe the sun at a distance
during some parts of the 22-yr cycle as a magnetic variable star (if
it were possible to observe variations of a few Gauss) with irregular
fluctuations and reversals in intervals of the order of a few da~~s. A
portion of this work was made possible by the Advanced Research Projects
Agency by means of a contract with the Lockheed Solar Observatory.
Title: Large-Scale Patterns of Solar Magnetic Fields
Authors: Bumba, V.; Howard, R. F.; Smith, S. F.
Bibcode: 1964Ast....69..535B
Altcode:
No abstract at ADS
Title: Unusual observation of a meteor train
Authors: Bumba, V.
Bibcode: 1963BAICz..14...22B
Altcode:
No abstract at ADS
Title: Contribution to the discussion of radial motions in sunspots
Authors: Bumba, V.
Bibcode: 1963BAICz..14..137B
Altcode:
No abstract at ADS
Title: Relation between motions and local magnetic fields in the
photosphere
Authors: Bumba, V.
Bibcode: 1963BAICz..14....1B
Altcode:
No abstract at ADS
Title: Slow change in the maximum intensity of the magnetic field
of regular spots
Authors: Bumba, V.
Bibcode: 1963BAICz..14..134B
Altcode:
No abstract at ADS
Title: Development of SPOT group areas in dependence on the local
magnetic field
Authors: Bumba, V.
Bibcode: 1963BAICz..14...91B
Altcode:
No abstract at ADS
Title: Auxiliary horizontal solar spectrograph at Ondřejov
Authors: Bumba, V.
Bibcode: 1963BAICz..14..102B
Altcode:
No abstract at ADS
Title: Polarization of light in solar spectrograph. I. Polarization
on coelostat mirrors
Authors: Bumba, V.; Topolová-Rů ŽiČková, B.
Bibcode: 1962BAICz..13...95B
Altcode:
No abstract at ADS
Title: Sunspot Magnetic Fields and Loop Prominences
Authors: Bumba, V.; Kleczek, Y.
Bibcode: 1962IAUTB..11Q.430B
Altcode:
No abstract at ADS
Title: Magnetic fields in sunspot umbrae
Authors: Bumba, V.
Bibcode: 1962BAICz..13...48B
Altcode:
No abstract at ADS
Title: Contribution to the study of the magnetic field in sunspot
umbrae
Authors: Bumba, V.
Bibcode: 1962BAICz..13...42B
Altcode:
No abstract at ADS
Title: A simple device for studying sunspot motions
Authors: Bumba, V.; Kleczek, F.
Bibcode: 1962BAICz..13..118B
Altcode:
No abstract at ADS
Title: Configuration of Magnetic Fields in Sunspot Umbrae
Authors: Bumba, V.
Bibcode: 1962IAUTB..11R.430B
Altcode:
No abstract at ADS
Title: On a sunspot group with an outstanding loop activity
Authors: Bumba, V.; Kleczek, J.
Bibcode: 1961Obs....81..141B
Altcode:
No abstract at ADS
Title: Magnetic fields in sunspot groups
Authors: Bumba, V.
Bibcode: 1961BAICz..12...82B
Altcode:
No abstract at ADS
Title: Note on Evershed's measurements of the magnetic field in a
chromospheric flare
Authors: Bumba, V.; Letfus, V.
Bibcode: 1961BAICz..12..114B
Altcode:
No abstract at ADS
Title: Active chromospheric phenomenon on the NW-limb of the Sun,
1960 August 20
Authors: Blaha, M.; Bumba, V.; Křivský, L.; Valníček, B.
Bibcode: 1961BAICz..12....7B
Altcode:
No abstract at ADS
Title: Emission in two directions by sources of increased radiation
on metre waves
Authors: Bumba, V.; Olmr, F.
Bibcode: 1960BAICz..11..254B
Altcode:
No abstract at ADS
Title: Chromospheric pre-flares
Authors: Bumba, V.; Křivský, L.
Bibcode: 1959BAICz..10..221B
Altcode:
No abstract at ADS
Title: The relation of motion in "unipolar" sun-spots to the magnetic
field in these spots
Authors: Bumba, V.
Bibcode: 1959BAICz..10..183B
Altcode:
No abstract at ADS
Title: On the penetration of solar magnetic fields into the
chromosphere
Authors: Severny, A. B.; Bumba, V.
Bibcode: 1958Obs....78...33S
Altcode:
No abstract at ADS
Title: Das Spektrum des Meteors 1954 Dezember 14, (Meteorspektra II)
Authors: Bumba, V.; Valníček, B.
Bibcode: 1956BAICz...7...18B
Altcode:
No abstract at ADS
Title: Eine Ergänzung zur Bemerkung über die Sonnentätigkeit und
die Meteore
Authors: Bumba, V.
Bibcode: 1955BAICz...6..141B
Altcode:
No abstract at ADS
Title: Eine Bemerkung über die Sonnentätigkeit und die Meteore
Authors: Bumba, V.
Bibcode: 1955BAICz...6..139B
Altcode:
No abstract at ADS
Title: The Meteor Spectra of the Perseid Shower 1953. First Part
Authors: Bumba, V.; Valniček, B.
Bibcode: 1955BAICz...6..108B
Altcode:
No abstract at ADS
Title: Einfluβ der groβen Meteorströme auf die Charaktervariationen
der geomagnetischen Tätigkeit
Authors: Bumba, V.
Bibcode: 1955BAICz...6....1B
Altcode:
No abstract at ADS
Title: Long Enduring Meteor Trains. I. Statistical Results
Authors: Bumba, V.
Bibcode: 1953BAICz...4..147B
Altcode:
No abstract at ADS
Title: Influence de l'angle horaire du Soleil et de la Lune sur les
altitudes météoriques
Authors: Bumba, V.
Bibcode: 1950BAICz...2...68B
Altcode:
No abstract at ADS
Title: Variation saisonnière des altitudes météoriques
Authors: Bumba, V.
Bibcode: 1949BAICz...1..125B
Altcode:
No abstract at ADS
Title: Influence de l'activité solaire sur le nombre des observations
de météores, de trainées météoriques et de chutes météoritiques
Authors: Bumba, V.
Bibcode: 1949BAICz...1...93B
Altcode:
No abstract at ADS
Title: Etudes meteoriques.
Authors: Bumba, V.; Link, F.
Bibcode: 1948PAICz..20....1B
Altcode:
No abstract at ADS