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Author name code: ambroz
ADS astronomy entries on 2022-09-14
author:"Ambroz, Pavel"
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Title: Deciphering the Deep Origin of Active Regions via Analysis
of Magnetograms
Authors: Dikpati, Mausumi; McIntosh, Scott W.; Chatterjee, Subhamoy;
Norton, Aimee A.; Ambroz, Pavel; Gilman, Peter A.; Jain, Kiran;
Munoz-Jaramillo, Andres
2021ApJ...910...91D Altcode:
In this work, we derive magnetic toroids from surface magnetograms
by employing a novel optimization method, based on the trust region
reflective algorithm. The toroids obtained in this way are combinations
of Fourier modes (amplitudes and phases) with low longitudinal
wavenumbers. The optimization also estimates the latitudinal width of
the toroids. We validate the method using synthetic data, generated
as random numbers along a specified toroid. We compute the shapes and
latitudinal widths of the toroids via magnetograms, generally requiring
several m's to minimize residuals. A threshold field strength is
chosen to include all active regions in the magnetograms for toroid
derivation, while avoiding non-contributing weaker fields. Higher
thresholds yield narrower toroids, with an m = 1 dominant pattern. We
determine the spatiotemporal evolution of toroids by optimally weighting
the amplitudes and phases of each Fourier mode for a sequence of five
Carrington Rotations (CRs) to achieve the best amplitude and phases for
the middle CR in the sequence. Taking more than five causes "smearing"
or degradation of the toroid structure. While this method applies no
matter the depth at which the toroids actually reside inside the Sun,
by comparing their global shape and width with analogous patterns
derived from magnetohydrodynamic (MHD) tachocline shallow water model
simulations, we infer that their origin is at/near the convection zone
base. By analyzing the "Halloween" storms as an example, we describe
features of toroids that may have caused the series of space weather
events in 2003 October-November. Calculations of toroids for several
sunspot cycles will enable us to find similarities/differences in
toroids for different major space weather events.
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Title: Derivation of Toroid Patterns from Analysis of Magnetograms
And Inferring Their Deep-origin
Authors: Chatterjee, S.; Dikpati, M.; McIntosh, S. W.; Norton, A. A.;
Ambroz, P.; Gilman, P.; Jain, K.; Munoz-Jaramillo, A.
2020AGUFMSH0020013C Altcode:
We employ a novel optimization method based on Trust Region Reflective
algorithm to derive magnetic toroids from surface magnetograms. Toroids
obtained are combinations of Fourier modes (amplitudes and phases)
with low longitudinal wavenumbers. After validating the method using
synthetic data generated as random numbers along a specified toroid,
we compute shapes and latitudinal-widths of toroids from magnetograms,
usually requiring several m 's to minimize residuals. By comparing
properties of these toroids with patterns produced in the bottom
toroidal band undergoing MHD evolution in a 3D thin-shell shallow-water
type model, we infer their deep origin at/near convention-zone's base
or tachocline. A threshold field-strength is chosen to include all
active regions in magnetograms for toroid derivation, while avoiding
non-contributing weaker fields. Higher thresholds yield narrower
toroids, with m = 1 dominant, implying that stronger active regions
are erupting from the core of the toroids at bottom. We determine the
spatio-temporal evolution of toroids by optimally weighting amplitudes
and phases of each Fourier mode for a sequence of 5 Carrington Rotations
(CRs) to get the best amplitude and phases for the middle CR in the
sequence. Taking more than 5 causes 'smearing' or degradation of toroid
structure. As an example case, we analyze 'Halloween' storms toroids,
and describe the features that might have caused the series of space
weather events in October-November of 2003. We compare features of
these toroids with analogous patterns derived from model-output. To find
similarities/differences in toroids for different major space weather
events, we will analyze long-term magnetograms for several solar cycles.
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Title: Horizontal flow below solar filaments
Authors: Ambrož, P.; Pötzi, W.
2018A&A...613A..39A Altcode:
Context. Observations of the internal fine structures of solar
filaments indicate that the threads of filaments follow magnetic
field lines. The magnetic field inside the filament has a strong
axial component. Some models of magnetic fields suggest that the
field structure in filaments could be caused by the horizontal plasma
velocity field near both sides below the filament, where observable
shearing effects from the axial component are expected. <BR /> Aims:
The horizontal velocity field in the vicinity of polarity inversion
lines is measured in order to determine, if it exhibits a systematic
movement that induces shear along the filament axis and convergence
perpendicular to the axis. <BR /> Methods: The horizontal velocity was
obtained from the displacement of supergranules, which were derived
from Doppler measurements in the solar photosphere. Dopplergrams
corrected for rigid rotation and p-mode oscillations were further
analyzed by local correlation tracking. <BR /> Results: Vector fields
of the horizontal velocities were measured in 16 areas during 8 time
intervals in the years 2000-2002 on both solar hemispheres, each for a
few consecutive days. For 64 selected filaments the nearby horizontal
velocity vectors were split up into a component along the filament axis
and a perpendicular component. <BR /> Conclusions: Differences between
the axial velocities on both sides of the filaments were calculated. In
almost all cases the velocity gradient corresponds to the inclination of
the threads observed in Hα images. The average transverse velocity does
not show any preferred tendency towards a divergence or convergence to
the filament axis. Testing the horizontal velocity for the creation of
the differential rotation profile in the photosphere reveals a strong
dependence of the averaging process on the scale of our velocities.
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Title: Václav Bumba (1925 - 2018)
Authors: Kotrč, Pavel; Heinzel, Petr; Sobotka, Michal; Ambrož,
Pavel; van Driel-Gesztelyi, Lidia
2018SoPh..293...40K Altcode:
No abstract at ADS
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Title: Horizontal Velocities in Solar Filament Channel
Authors: Ambrož, P.; Pötzi, W.
2013CEAB...37..495A Altcode:
Chromosphere fibrils oriented along the neutral line in close vicinity
of solar filaments create typical characteristics of the filament
channel. From systematic Doppler velocities measurements made at
Kanzelhöhe Solar Observatory with the Magneto Optic Filter (MOF)
we derived the horizontal velocity fields. Horizontal velocities were
determined in areas strongly connected with filament channels and also
outside these regions. Close along the filament axis in the direction
of the polarity inversion line a strong shear of the mean horizontal
velocities was detected.
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Title: Long-term Regularities in Distribution of Global Solar and
Interplanetary Magnetic Fields
Authors: Ambrož, P.
2013CEAB...37..637A Altcode:
The very close relationship between distributions of the dipole
component of a global solar magnetic field and interplanetary
magnetic sector structure is studied in detail during the last
three solar activity cycles. The sudden changes in the recurrence
period during different phases of the activity cycle are found and
the relationship between new active regions with emerging strong
magnetic flux, large-scale transport of background magnetic regions
and global magnetic structures with low resolution spherical modes is
investigated. Active regions are subordinate to the rules leading to
formation of global regularities which are observed in the magnetic
field near the Earth orbit.
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Title: An Insight into the Origin of Hvar Observatory
Authors: Valníček, B.; Bumba, V.; Ambrož, P.
2013CEAB...37..397V Altcode:
No abstract at ADS
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Title: Solar Hα and white light telescope at Hvar Observatory
Authors: Čalogović, J.; Dumbović, M.; Novak, N.; Vršnak, B.;
Brajša, R.; Pötzi, W.; Hirtenfellner-Polanec, W.; Veronig, A.;
Hanslmeier$, A.; Klvaňa, M.; Ambrož, P.
2012CEAB...36...83C Altcode:
Recently, the double solar telescope at Hvar Observatory was equipped
with the fourth generation of acquisition hardware and software. It
provides a valuable instrument to study rapid changes of chromospheric
and photospheric features in great detail. The telescope consists of
two Carl Zeiss refractors (photosphere d=217mm, chromosphere d=130mm)
mounted as one unit on a German parallax mounting. Using a field
of view of about 7 and 11 arcmin, it aims to produce high-resolution
high-cadence imaging of active regions on the Sun. New Pulnix TM-4200GE
12-bit CCD cameras allow to obtain time series with a cadence up to
30 images per minute.
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Title: Analysis of large-scale horizontal velocities and the magnetic
field on the sun during fast reorganization periods
Authors: Molodykh, S. I.; Ambroz, P.; Kovalenko, V. A.
2009Ge&Ae..49..860M Altcode:
The velocity field of large-scale magnetic structures during fast
reorganizations of the global solar magnetic field structure has been
analyzed. Some characteristic features of the velocity field have been
found during these periods. At that time, a considerable part of the
solar surface is occupied by regions with low horizontal velocities,
which correspond to the regions of positive and negative velocity
field divergence during the solar activity growth and decline phases,
respectively. Such character of changes in the velocity field during
these periods agrees with the previously proposed scenario of magnetic
field variations during global reorganizations of the magnetic field
structure. The average horizontal velocities during a Carrington
rotation and their divergence have been calculated for Carrington
rotations from 1646 to 2006. Relatively slow regular variations in
these parameters as well as their abrupt changes, observed during
different solar cycle phases, have been revealed. An increase in the
average horizontal velocity during the solar activity growth phase
is most probably caused by relative motions of the regions with a new
emerging magnetic flux. We assume that abrupt increases in the average
horizontal velocity divergence are related to fast reorganizations of
the magnetic field structure.
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Title: 3D Coronal Structures and Magnetic Field During the Total
Solar Eclipse of 29 March 2006
Authors: Ambrož, P.; Druckmüller, M.; Galal, A. A.; Hamid, R. H.
2009SoPh..258..243A Altcode:
The good quality of the observing sequence of about 60 photographs
of the white-light corona taken during the total solar eclipse
observations on 29 March 2006, in Al Sallum, Egypt, enable us to use
a new method of image processing for enhancement of the fine structure
of coronal phenomena. We present selected magnetic-field lines derived
for different parameters of the extrapolation model. The coincidence
of the observed coronal white-light fine structures and the computed
field-line positions provides a 3D causal relationship between coronal
structures and the coronal magnetic field.
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Title: Development of Source Surface Radius during Solar Cycles
Authors: Belik, M.; Ambroz, P.; Markova, E.
2008ESPM...122.111B Altcode:
The source surface radius presents one of the boundary condition in
the modeling of solar coronal magnetic field. Its value affect the
shape of the computed coronal magnetic structures. The pictures of
solar corona obtained during total solar eclipses and processed by
special numerical method, show very faint structures, extended to
the several solar radii. Under the assumption that these structures
represent a real magnetic situation in the corona, a value of the
source surface radius can be estimated through the analysis of their
shapes. We discuss some problems of calculation of its values and the
evolution of source surface radius during solar activity cycle.
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Title: Large-scale patterns, complexes of solar activity and ‘active
longitudes’
Authors: Ambrož, Pavel
2007HiA....14..277A Altcode:
Typical latitude zones and longitude sectors with a dominant occurrence
of newly emerging magnetic flux were systematically detected during
three last activity cycles. Two long time persistent longitude sectors
with the preferred occurrence of a new strong magnetic flux are
characteristic for magnetic flux distribution and their rotation rate
is latitude dependent in the relationship with differential rotation
rate. Recent new information about the large-scale flows in convection
zone relates to a concept of the expected giant cells and jets and
show a new relationship with different scales of the large-scale
circulation. Non-axially symmetric horizontal flow in upper part
of convection zone gives a good motivation for an extension of the
existing axially symmetric 2D models into new 3D concept.
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Title: Large-scale patterns, complexes of solar activity and
`active longitudes'.
Authors: Ambrož, P.
2006IAUJD...8E..53A Altcode:
A description of the current state of observations of large-scale
structures on the Sun is a main aim of presented review. Large-scale
structures with characteristic dimension larger than a typical active
region were found in different regions of the solar atmosphere,
as well as, below the photosphere. Recently new information about
the large-scale flows in convection zone up to solar photosphere
related with concept of the expected giant cells and jets and
show new relationship with different scales of the large-scale
circulation. Large-scale velocities together with large-scale magnetic
fields create physical base for the dynamo process, being responsible
for forcing and transforming of the magnetic field in and below the
photosphere. At the photosphere and chromosphere the occurrence of the
active regions and complexes of activity is probably influenced from
below, however their internal processes takes part on the production
of eruptive and other active phenomena, influencing an outer parts of
solar atmosphere. Large-scale background magnetic field distribution
determines the structure and evolution of the filament channels, as well
as, structure of the extended coronal loops, arcades, streamers, coronal
holes and polar caps. It is possible to follow an extended relationship
between the solar photosphere and the outer corona, as well as, between
the sector structures of the interplanetary magnetic fields. Large-scale
structures of the solar magnetic and velocity fields really represent
the non-axially symmetric features on the Sun and provoke an extension
of the still existing axially symmetric 2D models into new 3D concept.
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Title: Axially symmetric large-scale transport of the magnetic flux
during solar activity cycle
Authors: Ambrož, Pavel
2006IAUS..233...71A Altcode:
Transport of the solar background large-scale magnetic regions is
followed between individual consecutive magnetic synoptic charts derived
from observing data of Kitt Peak NSO. During many solar rotations the
horizontal magnetic flux displacement was described by large-scale
horizontal transport velocities, inferred in many points over the
whole solar photosphere. Large-scale transport velocities contains
from both axially symmetric and non-axially symmetric components. The
first one describes zonal and meridional global transport studied in
time interval during three last solar activity cycles. Cycle dependent
global velocities are found as values varying in heliographic latitude
and in the phase of the solar cycle.
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Title: Large-scale Transport of Magnetic Flux and Flows in Solar
Convection Zone
Authors: Ambrož, P.
2005ASPC..346....3A Altcode:
Horizontal transport of large-scale magnetic regions during the last
three solar activity cycles was studied. The surface displacement of
the magnetic regions was measured, and the horizontal velocity fields
were inferred. A non-homogeneous transport Aof the magnetic flux over
the solar surface, superposed on the global differential rotation and
meridional circulation was considered. A large-scale velocity with the
axially symmetric component and also with a large-scale non-axially
symmetric component of the horizontal velocity field varies during the
11-year activity cycle. A spatial distribution of horizontal flow,
horizontal divergence, and inferred relative magnetic helicity were
studied over nearly 370 individual Carrington rotations, and their
global values were derived from the three last solar activity cycles.
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Title: Contributon to Modeling of Coronal Magnetic Field
Authors: Belík, Marcel; Ambroz, P.; Marková, E.
2005ESASP.600E..78B Altcode: 2005dysu.confE..78B; 2005ESPM...11...78B
No abstract at ADS
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Title: Magnetic Helicity Generated together with the Evolution of
the Large-Scale Magnetic Fields
Authors: Ambrož, Pavel
2005HiA....13..134A Altcode:
Large-scale magnetic regions evolve their photospheric structure
relatively slowly during their lifetime for many months. Horizontal
transport velocities of the magnetic flux responsible for the evolution
are inferred for each whole Carrington rotation for time interval of
the last three activity cycles Nos. 21 22 and 23 i.e. from the year
1976 to the present. In the paper it is assumed that the causes of
the departure of the magnetic field in solar atmosphere from current
free configurations are magnetic transport velocities of the opposite
polarities in photosphere. For each Carrington rotation the value of the
current helicity as well as an available magnetic energy were computed
and localities with both enhanced values were selected. A possible
role of the large-scale flow and magnetic field in the process of
the current helicity formation is discussed. Changes of the latitude
profile of the helicity as well as the hemispheric dependence of the
helicity sign during the activity cycle are described.
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Title: Long-Term Dynamics of the Large-Scale Magnetic Structures
Authors: Ambrož, P.
2004SoPh..224...61A Altcode: 2005SoPh..224...61A
Large-scale magnetic field regions are evolving on a time scale of
many weeks and months and are also modified during the solar activity
cycle. The position of the regions are compared in a pair of consecutive
synoptic charts and the horizontal velocity field responsible for their
position changes, is inferred. Besides the axially symmetric zonal and
meridional drifts, relating to differential rotation and meridional
circulation, also non-axially symmetric velocity structures were
observed during the last three solar activity cycles. Changes of the
position and spatial distribution, as well as temporal variations of
the field strength, closely relate to the occurrence and variations
of other forms of solar activity such as sunspots, filaments and
prominences and coronal structures. In combination with 11-yr cyclic
changes of the large-scale velocity field, a new global dynamic regime
of the convection zone is described.
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Title: Spatial distribution, time evolution and rotation of the
large-scale total magnetic flux patterns on the Sun
Authors: Ambroz, Pavel
2003ESASP.535...59A Altcode: 2003iscs.symp...59A
Total intensity of the magnetic field is derived from the radial
values of large-scale magnetic field measured on WSO of Stanford
University. Horizontal component of the magnetic field in and above the
photosphere was derived by computing of the current free approximation,
all for each Carrington rotation in the time interval from year 1976 to
2000. Spatial distribution of the enhanced regions of the total magnetic
flux was studied during the activity cycle. Time-longitude evolution
of the total flux patterns was tested in relationship with both
positive and negative polarities evolution in solar photosphere. Close
relationship between enhanced magnetic flux regions and the green
corona bright regions is found. The study brings a new light on the
problem of the "coronal rotation".
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Title: Magnetic Helicity Generated by Large-Scale Magnetic Field
Authors: Ambroz, Pavel
2003IAUJD...3E..14A Altcode:
Large-scale magnetic regions evolve their photospheric structure
relatively slowly during their lifetime for many months. Horizontal
transport velocities of the magnetic flux responsible for the evolution
are inferred for each whole Carrington rotation for time interval of
the last three activity cycles Nos. 21 22 and 23 i.e. from the year
1976 to the present. In the paper it is assumed that the causes of
the departure of the magnetic field in solar atmosphere from current
free configurations are magnetic transport velocities of the opposite
polarities in photosphere. For each Carrington rotation the value of the
current helicity as well as an available magnetic energy were computed
and localities with both enhanced values were selected. A possible
role of the large-scale flow and magnetic field in the process of
the current helicity formation is discussed. Changes of the latitude
profile of the helicity as well as the hemispheric dependence of the
helicity sign during the activity cycle are described.
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Title: Large-scale magnetic field evolution on different time scales
Authors: Ambrož, Pavel
2002ESASP.506..827A Altcode: 2002svco.conf..827A; 2002ESPM...10..827A
Horizontal transport of large-scale magnetic field in course of last
three solar activity cycles was studied. The specific displacement of
magnetic regions was followed during their lifetime and the horizontal
velocity field was inferred. The velocity field was analyzed during the
25 years time interval and cyclic changes of the velocity values were
obtained. Velocities were studied in the 320 individual synoptic charts
with spatial resolution 5 heliographic degrees in both longitudinal and
latitudinal directions. A non-homogeneous transport of the magnetic flux
over the solar sphere, superposed on the global differential rotation
and meridional circulation was revealed. Both zonal and meridional
global axially symmetric velocities vary during the 11-year activity
cycle. The non-axially symmetric velocity field creates the large-scale
flow structures with lifetime from 4 to 6 Carrington rotations and
characteristic scale length from 40 to 60 heliographic degrees in the
zonal belt between +/-60 degrees of the latitude. Also RMS velocity
of the non-axially symmetric velocity field varies during the 11-year
activity cycle. Long-term relationship between cyclic variations of
the velocity parameters and the magnetic flux values is discussed.
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Title: Evolving large-scale magnetic field and the global convection
on the Sun
Authors: Ambroz, Pavel
2002ESASP.505..333A Altcode: 2002solm.conf..333A; 2002IAUCo.188..333A
Large-scale magnetic field on Kitt Peak synoptic charts was investigated
for many pairs of consecutive Carrington rotations of the last three
solar activity cycles. Evolution of the large-scale magnetic regions
can be described by horizontal transport velocity field in many grid
points of the solar photosphere. A possible relationship between
the current free magnetic field and the deformed force-free magnetic
configurations is studied. The aim of the study is to demonstrate a
role of dynamical properties of the large-scale magnetic flux during
formation of the helical magnetic structures and a preparation of the
pre-flare configurations in the solar atmosphere.
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Title: Large-scale transport of magnetic flux on the Sun and flare
productivity
Authors: Ambrož, Pavel; Schroll, Alfred
2002ESASP.477...73A Altcode: 2002scsw.conf...73A
Horizontal transport of the large-scale magnetic field during the last
three solar activity cycles was studied. The specific displacement of
the magnetic regions was followed and the horizontal velocity field
was inferred. A non-homogeneous transport of the magnetic flux over
the solar surface, superposed on the global differential rotation and
meridional circulation was discovered. Large-scale velocities with the
axially symmetric component and also with the large-scale non-axially
symmetric component of the horizontal velocity field varies during
the 11-year activity cycle. A spatial distribution of the available
magnetic energy was computed and the relationship with the flare
productivity was found.
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Title: JOSO national report 2000-2001 - Czech Republic
Authors: Ambroz, P.; Kotrc, P.
2002joso.book...50A Altcode:
Solar research in the Czech Republic is performed at the Astronomical
Institute of the Academy of Sciences of the Czech Republic in
Ondrejov. The regular optical and radio observations are also carried
out at the Upice Observatory (east-northern Bohemia), photospheric and
chromospheric observations are also regularly made at the Valasské
Mezirící Observatory (Moravia).
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Title: Proper motion of solar filaments
Authors: Ambrož, P.; Schroll, A.
2002A&A...381..300A Altcode:
Movement of solar filaments relative to the Carrington reference
system is considered to be an appropriate quantity to characterize
the horizontal transport of magnetic flux in the solar photosphere
and chromosphere. A new method of measurement of both zonal and
meridional velocities was developed using an extensive set of Hα
observations. The velocity field was derived for many filaments during
a few consecutive days and for different Carrington rotations. The
proper motion of different parts of the filament relative to the
Carrington reference system was determined. A velocity variation
with a time-scale of about 10 hours was discovered. The presence of a
non-axially symmetric horizontal velocity component in the filamentary
motion was confirmed. The latitude- and longitude-dependent distribution
of the horizontal velocity field was detected. The relationship between
the horizontal velocities of solar filaments and the horizontal
velocity field derived from background solar magnetic fields was
found. In this paper the sources of errors are also analyzed in
detail. Many measurements were disqualified by ill-defined contours of
the filaments. The systematic errors, caused by the unknown height
and shape of the filaments, are estimated. Only velocity values
more accurate than 100 m s<SUP>-1</SUP> were used in the study. The
deviations of the mean horizontal velocities of filaments, magnetic
field and sunspots resulting from the selection effect in their position
on the Sun were interpreted.
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Title: Semiempirical Modeling of Large-Scale Flow on the Sun
Authors: Ambrož, P.
2001SoPh..199..251A Altcode:
A horizontal velocity field is used to describe the large-scale
transport of magnetic flux over the whole solar photosphere. The
image of the 2-D large-scale flow on the sphere is derived from the
trajectories of the independent free testing particles driven by the
derived velocity field. The horizontal flow displays a velocity gradient
and an eddy structure. The horizontal divergence of the vector field is
used to describe the cellular-like patterns and limits of the discrete
large-scale flow structures. The slow- and long-lived temporal evolution
of the flow structures is described.
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Title: Large-Scale Transport of Magnetic Flux on the sun
Authors: Ambrož, P.
2001SoPh..198..253A Altcode:
The structure of the large-scale background magnetic field evolves in
time and space. The large-scale horizontal transport velocity field of
the magnetic flux patterns was inferred over the whole solar photosphere
in the course of two solar activity cycles from year 1976 to 1999. The
method of velocity determination and the testing procedures of the
velocity accuracy are presented. The non-axially symmetric component
of the horizontal velocity was found and both zonal and meridional
velocity regions were described. The horizontal large-scale transport
velocity regions vary in shape and the intensity during different phases
of the 11-year solar activity cycle. The total horizontal transport
velocity is characterized by the presence of variable amounts of the
vector field vortices with symmetric orientation relative to the solar
equator. The zonal velocity regions, distributed inside of the zonal
belt limited by latitudes ± 35°, are persistent for about 4 Carrington
rotations. Recurrent structures of similar velocity distributions are
not coherent over the whole solar photosphere.
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Title: Large-scale Motion of Solar Filaments
Authors: Ambroz, P.; Schroll, Alfred
2000JApA...21..205A Altcode:
No abstract at ADS
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Title: Large-scale Flow and Transport of Magnetic Flux in the Solar
Convection Zone
Authors: Ambrož, P.
2000JApA...21..315A Altcode:
No abstract at ADS
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Title: Cyclic Variation of Solar Large-Scale Convection
Authors: Ambroz, P.
2000ESASP.463..277A Altcode: 2000sctc.proc..277A
No abstract at ADS
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Title: Proper Motion of Solar Filaments
Authors: Ambroz, P.; Schroll, A.
1999ASSL..239..247A Altcode: 1999msa..proc..247A
Precise measurements of heliographic position of solar filaments
were used for describing the proper motion of solar filaments on the
time-scale of one day. Only the velocity values more accurate than
100 m s^{-1} were used for the study. The filaments have a tendency to
make a shaking or waving of the external structure and also to make a
general movement of whole filament body, coinciding with the transport
of the magnetic flux in the photosphere.
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Title: Large-scale transport of magnetic flux in solar convection
zone.
Authors: Ambrož, P.
1999joso.proc...91A Altcode:
Horizontal displacements of the photospheric magnetic flux in zonal
and meridian directions are interpreted as a partial consequence of
horizontal large-scale velocity field, driven in deeper layers by
giant convection. Determination of horizontal streamlines of solar
plasma for different phases of the 11 year solar activity cycle was
made according to the inferred large-scale velocity fields. The flow
systems are horizontally limited, creating the cellular-like patterns
with up-flow in the center and the down-flow on the boundaries. The
flow patterns indicate the giant convection cells, many of them
were detected during a period of more than four Carrington rotations
(about 120 days). The characteristic distribution of the large-scale
horizontal eddies (with characteristic scale lengths from 350 to 490
Mm) was found in the broad equatorial zone, limited between about 50 -
60 degrees of latitude in both hemispheres. The typical dimension of
the observed velocity patterns varies with the spatial averaging of
the velocity signal. The zonal mean of the zonal component of the
flow relates with the differential rotation law, but the latitude
dependence of the rotation rate is lower than the usually accepted
surface data. The possible influence of radial dependence on the
derived rotation rate is considered.
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Title: A comment on the structure of the quiescent prominence magnetic
field configuration
Authors: Ambrož , P.
1998PAICz..88..218A Altcode:
No abstract at ADS
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Title: Large-Scale Flow in the Solar Convection Zone
Authors: Ambroz, P.
1997HvaOB..21....9A Altcode:
A brief review of results, dealing with the large-scale velocity field
in the solar convection zone, is presented. The information about the
velocity patterns in the photosphere is summarized and the discrepancies
of few contradictory results are stressed. The large-scale velocities
measured by Doppler and "tracer" methods are mentioned. Special interest
is oriented on the large-scale and the global flow, inferred from the
horizontal transport of the background magnetic flux. The possible
relationship between the spatial resolution of velocity structure and
the depth profile of the mean zonal flow is formulated. The possibility
to construct a 3D structure of flow in the convection zone is suggested.
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Title: A new understanding of the coronal shape changes during the
solar cycle.
Authors: Sýkora, J.; Ambrož, P.
1997ASIC..494..111S Altcode: 1997topr.conf..111S
Shape and flattening of the solar corona observed on July 11, 1991
eclipse and confrontation of them with calculated topology of coronal
magnetic field and with known variations of the coronal flattening
index as a function of the phase of sunspot cycle initiated doubts on
acceptability of Ludendorff's definition of the solar corona flattening
and, consequently, on real extent of the mentioned variations.
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Title: Structural changes of light-bridge related with flare
occurrence.
Authors: Ambrož, P.
1997joso.proc...49A Altcode:
No abstract at ADS
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Title: Evidence for prolonged acceleration based on a detailed
analysis of the long-duration solar gamma-ray flare of June 15, 1991
Authors: Akimov, V. V.; Ambrož, P.; Belov, A. V.; Berlicki, A.;
Chertok, I. M.; Karlický, M.; Kurt, V. G.; Leikov, N. G.; Litvinenko,
Yu. E.; Magun, A.; Minko-Wasiluk, A.; Rompolt, B.; Somov, B. V.
1996SoPh..166..107A Altcode:
Gamma-ray emission extending to energies greater than 2 GeV and lasting
at least for two hours as well as 0.8-8.1 MeV nuclear line emission
lasting 40 min were observed with very sensitive telescopes aboard
the GAMMA and CGRO satellites for the well-developed post-flare loop
formation phase of the 3B/X12 flare on June 15, 1991. We undertook
an analysis of optical, radio, cosmic-ray, and other data in order to
identify the origin of the energetic particles producing these unusual
gamma-ray emissions. The analysis yields evidence that the gamma-rays
and other emissions, observed well after the impulsive phase of the
flare, appear to be initiated by prolonged nonstationary particle
acceleration directly during the late phase of the flare rather than by
a long-term trapping of energetic electrons and protons accelerated at
the onset of the flare. We argue that such an acceleration, including
the acceleration of protons up to GeV energies, can be caused by
a prolonged post-eruptive energy release following a coronal mass
ejection (CME), when the magnetic field above the active region,
strongly disturbed by the CME eruption, relaxes to its initial state
through magnetic reconnection in the coronal vertical current sheet.
---------------------------------------------------------
Title: A Rossby type wave influencing the restructuring of the solar
large-scale magnetic field.
Authors: Ambrož, P.
1996joso.proc..142A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Book reviews
Authors: Cliver, E. W.; Somov, B. V.; Ambrož, P.
1995SoPh..160..401C Altcode: 1995SoPh..160..401P
No abstract at ADS
---------------------------------------------------------
Title: Book Review: Magnetic fields of celestial bodies / Kluwer, 1994
Authors: Ye, S. H.; Ambroz, P.
1995SoPh..160..402Y Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Large-Scale Velocity Field Measured by Doppler and Local
Correlation Tracking Methods
Authors: Ambroz, P.; Robillot, J. M.; Bocchia, R.
1995ESASP.376b.233A Altcode: 1995soho....2..233A; 1995help.confP.233A
No abstract at ADS
---------------------------------------------------------
Title: Temporal Devalpment of the Heliospheric Magnetic Field Topology
as Confirmed by Eclipse Observations of the Solar Corona Streamers
Authors: Sykora, J.; Ambroz, P.
1995ICRC....4..509S Altcode: 1995ICRC...24d.509S
No abstract at ADS
---------------------------------------------------------
Title: Structure, Photometry and Polarimetry of the White-Light
Corona as Observed from Criciuma (Brazil) on November 3, 1994
Authors: Sýkora, J.; Pintér, T.; Ambroz, P.
1995pist.conf...23S Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The structure and physical properties of the quiet corona as
inferred from the July 11, 1991 solar eclipse data
Authors: Sykora, J.; Ambroz, P.; Badalyan, O. G.
1994AdSpR..14d..69S Altcode: 1994AdSpR..14...69S
We were successful in observing the linear polarization of the solar
corona in the white light and in the light of the green emission
line 530.3 nm during the July 11, 1991 total solar eclipse (La Paz,
Mexico). Preliminary analysis reveals remarkable differences in
the degree of polarization for both sets of data, particularly for
the distribution of polarization around the sun's limb. The upper
theoretical limits of the degree of polarization are compared with
our results. The real structure of the corona is compared with the
calculated coronal magnetic field. The rather unusual shape and
structure of the eclipse corona in a given of the solar cycle are
discussed in connection with a definition of coronal flattening.
---------------------------------------------------------
Title: Evolution of Large-Scale Coronal Structures
Authors: Ambroz, P.
1994scs..conf...29A Altcode: 1994IAUCo.144...29A
The large-scale coronal structures observed during the sporadically
visible solar eclipses were compared with the numerically extrapolated
field-line structures of coronal magnetic field. A characteristic
relationship between the observed structures of coronal plasma and
the magnetic field line configurations was determined. The long-term
evolution of large scale coronal structures inferred from photospheric
magnetic observations in the course of 11- and 22-year solar cycles
is described. A relation between the large-scale photospheric magnetic
field evolution and the coronal structure rearrangement is demonstrated.
---------------------------------------------------------
Title: Calculated Coronal Magnetic Fields and Their Comparison with
the Coronal Structures as Observed during Five Solar Eclipses
Authors: Ambroz, P.; Sykora, J.
1994scs..conf..559A Altcode: 1994IAUCo.144..559A
For solar corona observations during five solar eclipses (1973 - 1991)
the authors calculated for the eclipse days the coronal magnetic field
by extrapolation from the photosphere. Comparison of the observed and
calculated coronal structures is carried out and some peculiarities of
this comparison, related to the different phases of the solar cycle,
are presented.
---------------------------------------------------------
Title: FeXIV Line Emission Polarization of the July 11, 1991 Solar
Corona
Authors: Sykora, J.; Rybak, J.; Ambroz, P.
1994scs..conf..541S Altcode: 1994IAUCo.144..541S
High resolution images, obtained during July 11, 1991 total solar
eclipse, allowed to estimate the degree of solar corona polarization
in the light of Fe XIV 530.3 nm emission line and in the white light,
as well. Very preliminary analysis reveals remarkable differences in
the degree of polarization for both sets of data, particularly as for
level of polarization and its distribution around the Sun's limb.
---------------------------------------------------------
Title: Large-scale solar convection.
Authors: Ambrož, P.
1994soro.conf..137A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Comparison of the July 11, 1991 Eclipse Coronal Structures
with the Observed and Calculated Magnetic Fields of the Solar Corona
Authors: Ambrož, P.; Sýkora, J.
1994emsp.conf..121A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Evolutionary Characteristics of Large-Scale Magnetic and
Velocity Fields
Authors: Ambroz, P.
1993ASPC...46..495A Altcode: 1993IAUCo.141..495A; 1993mvfs.conf..495A
No abstract at ADS
---------------------------------------------------------
Title: Variation of the large-scale magnetic field structure.
Authors: Ambrož, P.
1993sova.conf...62A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Book-Review - the Sun - an Introduction
Authors: Stix, M.; Ambroz, P.
1991BAICz..42..329S Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The Solar Global Velocity Field Inferred from Developing
Large-Scale Magnetic Field Structures
Authors: Ambrož, P.
1990PDHO....7...50A Altcode: 1990dysu.conf...50A; 1990ESPM....6...50A
Changes created during the development of large-scale background
magnetic fields are used for the horizontal velocity field
determination. A computer algorithm to determine transverse velocities
in the photosphere has been developed. First results are presented
examples of photospheric velocity maps are shown.
---------------------------------------------------------
Title: Book Review: Solar and stellar physics. / Springer-Verlag, 1987
Authors: Ambroz, P.
1989BAICz..40Q.267A Altcode: 1989BAICz..40Q.267S
No abstract at ADS
---------------------------------------------------------
Title: Book Review: Astrophysics of the sun. / CUP, 1988
Authors: Ambroz, P.
1989SoPh..123..193A Altcode: 1989SoPh..123..193Z
No abstract at ADS
---------------------------------------------------------
Title: Book reviews
Authors: Švestka, J.; Ambrož, P.; Fabbri, Roberto; Dryer, M.
1989SoPh..123..193S Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The Global Horizontal Circulation on the Sun
Authors: Ambroz, P.
1987BAICz..38..110A Altcode:
Using H-alpha synoptic charts of the distribution of the background
magnetic fields in the solar photosphere, the paper characterizes
the evolution, structure and distribution of the regions of the two
magnetic polarities and their boundaries. Active regions are formed
exclusively in places where the global circulation displays maximum
vorticity. Filaments occur in the regions where the value of the
velocity gradient is high, perpendicular to the filament axis. The
condition for these two manifestations of solar activity to form is
the presence of the boundary between the polarities of the background
magnetic field.
---------------------------------------------------------
Title: Connection of the large-scale solar magnetic and velocity
fields withthe solar active phenomena.
Authors: Ambroz, Pavel
1987PAICz..66..117A Altcode: 1987eram....1..117A
The paper characterizes the evolution, structure and areal distribution
of the large-scale background magnetic fields in the solar photosphere.
---------------------------------------------------------
Title: The relation between the large-scale solar magnetic field
distribution and the global horizontal circulation in the photosphere
Authors: Ambrož, P.
1986CoSka..15..501A Altcode:
Using H-alpha Synoptic Charts (SGD), the character of the development
of the structure and distribution of the regions of both magnetic
polarities and their boundaries are derived. A procedure was found of
describing qualitatively the direction of the horizontal streaming of
solar photospheric plasma under the assumption of divergence-free flow.
---------------------------------------------------------
Title: Astronomy on the 6th Europhysical Conference in Prague.
Authors: Ambrož, P.; Grygar, J.
1985Rise...66...31A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The wind protection of the Hvar solar telescope
Authors: Ambroz, P.
1985HvaOB...9...33A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Location of sources of solar noise storms relative to the
structure of extrapolated coronal magnetic fields.
Authors: Ambrož, P.
1983ITABO..57..171A Altcode:
A comparison is made of the positions of sources of solar radio
noise storms, observed at 169 MHz, with the structure of the lines
of force of the extrapolated coronal magnetic field in a current-free
approximation. The typical position of the permanent radio source was
found at the top of the coronal arch connecting the active region
with the opposite polarity of the background magnetic field in its
immediate vicinity. No direct relation was found between the flare
activity in the active region and the presence of the radio source.
---------------------------------------------------------
Title: Location of sources of solar noise storms relative to the
structure of extrapolated coronal magnetic fields.
Authors: Ambrož, P.
1983PDHO....5..145A Altcode: 1984PDHO....5..145A
A comparison is made of the positions of sources of solar radio
noise storms, observed at 169 MHz, with the structure of the lines
of force of the extrapolated coronal magnetic field in a current-free
approximation. The typical position of the permanent radio source was
found at the top of the coronal arch connecting the active region with
the opposite polarity of the background magnetic field in its immediate
vicinity. No direct relation was found between the flare activity in
the active region and the presence of the radio source. A hypothesis
is presented concerning the relation between the occurrence of noise
storm sources and the process of evolutionary reconnection of the
coronal magnetic field.
---------------------------------------------------------
Title: Solar Physics at Hvar Observatory
Authors: Ambroz, P.; Ruzdjak, V.
1982HvaOB...6...89A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Location of sources of solar noise storms relative to the
structure of extrapolated coronal magnetic fields
Authors: Ambrož, P.
1982nsco.work..171A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Extrapolated coronal magnetic fields on the Sun
Authors: Ambroz, P.
1980HvaOB...4...31A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Statistical Method of Superposition of Epochs. I. Methodical
Analysis and Some Criteria of Application
Authors: Ambroz, P.
1979BAICz..30..114A Altcode:
The statistical method of superposition of epochs, referred to the zero
day, is analyzed. Some new criteria of statistical significance of
the result have been formulated. A method of testing the persistence
of data sets and determining the empirical probability of realization
of the statistical result is proposed.
---------------------------------------------------------
Title: About the Conditions for Solar Observations at the Hvar
Observatory
Authors: Ambroz, P.
1979HvaOB...3...37A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Solar double telescope at the Hvar Observatory
Authors: Ambroz, P.; Bumba, V.; Havlicek, K.; Ptacek, J.; Suda, J.
1977HvaOB...1...15A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: About the Relation Between the Limb Effect of the Redshift
on the Sun and the Large-Scale Distribution of Solar Activity
Authors: Ambroz, P.
1976IAUS...71..113A Altcode:
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.
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.
1976str..book...15A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Physiology of quiescent filaments.
Authors: Ambroz, P.; Kleczek, J.
1976str..book...99A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Physiology of quiescent filaments
Authors: Ambrož, P.; Kleczek, J.
1976CoSka...6...99A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The Relation Between Chromospheric and Photospheric Structures
in Sunspot Groups
Authors: Bumba, V.; Ambroz, P.
1974IAUS...56..183B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Structural Changes and Regularities in the Distribution of
Calcium Flocculae on the Solar Surface in the Course of Cycle 19
Authors: Ambrož, P.
1973BAICz..24...80A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Relation of the Large-Scale Distribution of Activity on the
Solar Surface and of the Fluctuations of Some Activity Indices in
the Course of Cycle 19
Authors: Ambrož, P.
1973BAICz..24...88A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: A Comment on the Seasonal Variations of Solar Activity
Authors: Ambrož , P.
1973BAICz..24..130A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Graphical method of studying the distribution of the
macrostructure of solar activity
Authors: Ambrož , P.
1972BAICz..23..232A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Abstracts of papers from other journals
Authors: De Feiter, L. D.; Vassilyeva, G.; Henoux, J. -C.; Ambrož,
Pavel
1971SoPh...20..517D Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Planetary Influences on the Large-Scale Distribution of
Solar Activity
Authors: Ambrož, P.
1971SoPh...19..480A 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.
1971IAUS...43..696A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Large Scale Distribution of Magnetic Regions, Ca II Plages,
Filaments and Sunspots on the Solar Surface
Authors: Ambrož, P.
1971PDHO....2...29A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Structure of the solar corona.
Authors: Ambroz, P.
1970Kozmo...1....8A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Abstracts of papers from other journals
Authors: Stepanyan, N.; Pasachoff, Jay M.; Ambrož, P.; Vassilyeva,
G.; Henoux, J. -C.; Fokker, A. D.; De Feiter, L. D.; Gussmann, E. A.;
Uchida, Y.; Namba, O.
1969SoPh....8..491S Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Abstracts of papers from other journals
Authors: Pasachoff, Jay M.; AmbroŽ, P.; Namba, O.
1969SoPh....8..248P Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Nekteré pracovní metody ve slunecní fyzice (Some working
methods in solar physics).
Authors: Ambroz, P.
1969KosRo...7....1A Altcode:
No abstract at ADS
