scholarly journals Manifestations of Solar Magnetic Fields

1998 ◽  
Vol 11 (2) ◽  
pp. 857-860
Author(s):  
S.K. Solanki
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Solar Magnetic Field ◽  
Magnetic Activity ◽  
The Sun ◽  
Solar Magnetic Fields ◽  
Quiet Sun ◽  
Solar Magnetic Activity

AbstractThe magnetism of the Sun manifests itself in innumerable ways, many of which constitute what is referred to as solar magnetic activity, while others are counted among the phenomena of the quiet Sun. After a brief overview of the structure of the solar magnetic field, a few examples of its manifestations are pointed out.

scholarly journals Analog Video Magnetograms in Real Time

1971 ◽  
Vol 43 ◽  
pp. 76-83 ◽  
Author(s):  
R. C. Smithson ◽  
R. B. Leighton
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Solar Magnetic Field ◽  
Solar Spectrum ◽  
Zeeman Splitting ◽  
The Other ◽  
Line Of Sight ◽  
Zero Field ◽  
The Sun ◽  
Solar Magnetic Fields

For many years solar magnetic fields have been measured by a variety of techniques, all of which exploit the Zeeman splitting of lines in the solar spectrum. One of these techniques (Leighton, 1959) involves a photographic subtraction of two monochromatic images to produce a picture of the Sun in which the line-of-sight component of the solar magnetic field appears as various shades of gray. In a magnetogram made by this method, zero field strength appears as neutral gray, while magnetic fields of one polarity or the other appear as lighter or darker areas, respectively. Figure 1 shows such a magnetogram.

RSFP PREDICTIONS FOR TRANSVERSE SOLAR MAGNETIC FIELD DISTRIBUTION FROM SOLAR NEUTRINO DATA

1998 ◽  
Vol 13 (15) ◽  
pp. 1163-1170 ◽  
Author(s):  
B. C. CHAUHAN ◽  
U. C. PANDEY ◽  
S. DEV
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Field Distribution ◽  
Magnetic Moment ◽  
Solar Neutrino ◽  
Solar Magnetic Field ◽  
Magnetic Field Distribution ◽  
The Sun ◽  
Solar Magnetic Fields ◽  
The Magnetic Field

Even though the standard solar model (SSM) has been very successful in predicting the thermal and nuclear evolution of the Sun, it does not throw enough light on solar magnetic activity. In the absence of a generally accepted theory of solar dynamo, various general arguments have been put forth to constrain solar magnetic fields. In the absence of reliable knowledge of solar magnetic fields from available astrophysical data, it may be worthwhile to constrain the solar magnetic fields from solar neutrino observations assuming Resonant Spin-Flavor Precession (RSFP) to be responsible for the solar neutrino deficit. The configuration of solar magnetic field derived in this work is in reasonably good agreement with the magnetic field distribution proposed by Akhmedov et al. (Sov. Phys. JETP68, 250 (1989)). However, the magnetic field distribution in the radiation zone used by Pulido (Phys. Rep.211, 167 (1992)) is ruled out. The magnitude of the magnetic field in the radiation and convective zones of the Sun are very sensitive to the value chosen for the neutrino magnetic moment. However, any change in the value of neutrino magnetic moment does not affect the magnetic field distribution as it only scales the magnetic field strength at different points by the same amount.

scholarly journals Progress in the Measurement of Solar Magnetic Fields

1993 ◽  
Vol 141 ◽  
pp. 149-155 ◽  
Author(s):  
Guoxiang Ai
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
White Light ◽  
Historical Development ◽  
Solar Magnetic Field ◽  
Solar Physics ◽  
Monochromatic Light ◽  
Velocity Fields ◽  
Solar Magnetic Fields ◽  
Optical Instruments

AbstractThe historical development of optical instruments for solar physics is outlined, from white light to unpolarized and polarized monochromatic light, to Stokes profiles and simultaneous fields of view, from points to lines, plane to cube. An evolutionary series and classificaton of instruments for the solar magnetic field is described. As a next step the 2-D real time polarizing spectrograph has been proposed. The planned instruments in China for measurements of solar magnetic and velocity fields are briefly introduced.

scholarly journals Magnetic fields and dynamics of the Sun's interior

2008 ◽  
Vol 4 (S259) ◽  
pp. 147-158
Author(s):  
Alexander G. Kosovichev
Keyword(s):  
Magnetic Fields ◽  
Physical Mechanism ◽  
Active Regions ◽  
Magnetic Activity ◽  
Solar Interior ◽  
Global Dynamics ◽  
The Sun ◽  
New Knowledge ◽  
Solar Magnetic Activity ◽  
Key Questions

AbstractAdvances in helioseismology provide new knowledge about the origin of solar magnetic activity. The key questions addressed by helioseismology are: what is the physical mechanism of the solar dynamo, how deep inside the Sun are the magnetic fields generated, how are they transported to the surface and form sunspots? Direct helioseismic signatures of the internal magnetic fields are weak and difficult to detect. Therefore, most of the information comes from observations of dynamical effects caused by the magnetic fields. I review results of recent helioseismic observations of the magnetohydrodynamics of the solar interior on various scales, including global dynamics associated with the dynamo processes, and formation of sunspots and active regions.

scholarly journals Large-Scale Solar Magnetic Fields

1976 ◽  
Vol 71 ◽  
pp. 47-67 ◽  
Author(s):  
V. Bumba
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Field Distribution ◽  
Large Scale ◽  
Solar Magnetic Field ◽  
Magnetic Measurements ◽  
Preliminary Investigation ◽  
Longitudinal Distribution ◽  
Solar Magnetic Fields ◽  
Background Fields

The characteristics of the large-scale distribution of the solar magnetic fields on the basis of a series of solar magnetic synoptic charts covering more than 15 years of observations are given. The major part of our information concerns the morphology and only some results deal with the kinematics of the field distribution. Results of averaged solar magnetic field fluxes and polarity reversal studies as well as of preliminary investigation of the very-low angular resolution magnetic measurements are given. The regular zonal and sectoral distribution of photospheric background fields, the different role or visibility of structures in both polarities is discussed. The reflection of both main types of the longitudinal distribution of large-scale solar background magnetic fields (the 27-day, the 28–29-day successions, the ‘supergiant’ structures) in the interplanetary magnetic field distribution is also considered.

scholarly journals [no title]

1977 ◽  
Vol 4 (2) ◽  
pp. 223-239 ◽  
Author(s):  
J. Harvey
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Spatial Resolution ◽  
Small Scale ◽  
Solar Photosphere ◽  
The Sun ◽  
Solar Magnetic Fields ◽  
Structure And Dynamics ◽  
Physical Problems ◽  
Observational Techniques

If the Sun is observed like a star, without spatial resolution, its magnetic field seldom exceeds 1 Gauss. But with high spatial resolution the field is seen to be largely concentrated into kG structures. Observations of the structure and dynamics of solar magnetic fields can therefore provide a guide to the nature of magnetic fields of other stars which cannot be resolved. Solar activity and the structure of the chromosphere and inner corona are intimately linked with magnetism and a complete understanding of these features often depends on magnetic field details. There are unsolved physical problems involving solar magnetic fields which have challenged many physicists. For example, confinement of small-scale fields in kG structures is a problem of current interest (Parker, 1976; Piddington, 1976; Spruit, 1976). Solar observers are no less challenged since the Sun presents us with a complicated magnetic field having a range of scales from global to less than the scale of our best observations as illustrated in Figures 1, 2, and 3. This paper is a survey of observational techniques and results at the small-scale end of the spectrum of sizes in the solar photosphere. This topic has been frequently reviewed (e.g. Athay, 1976; Beckers, 1976; Deubner, 1975; Howard, 1972; Mullan, 1974; Severny, 1972; Stenflo, 1975) so that recent work is emphasized here.

scholarly journals Transient Events and Their Solar Magnetic Field

1998 ◽  
Vol 11 (2) ◽  
pp. 877-879
Author(s):  
J.-C. Vial
Keyword(s):  
Magnetic Field ◽  
Particle Acceleration ◽  
Magnetic Fields ◽  
Coronal Mass Ejections ◽  
Solar Magnetic Field ◽  
Solar Magnetic Fields ◽  
Radio Network ◽  
Excellent Review ◽  
X Ray ◽  
Transient Events

Excellent review papers have been presented in this session by S. Solanki (Manifestations of solar magnetic fields), K. Dere (Coronal Mass Ejections and interplanetary ejecta) and W. Droege (Particle acceleration by waves and fields) and the relevant texts can be found in this volume.The Joint Discussion benefited from three contributed papers: X-Ray/Radio network flares of the quiet Sun by A.O. Benz, S. Krucker, L.W. Acton, and T.S. Bastian (presented by A.O. Benz) Radio observations of coronal X-ray jets by M.R. Kundu

scholarly journals Global Evolution of Photospheric Magnetic Fields

1990 ◽  
Vol 138 ◽  
pp. 281-295
Author(s):  
V. I. Makarov ◽  
K. R. Sivaraman
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Large Scale ◽  
Active Regions ◽  
Magnetic Activity ◽  
Field Pattern ◽  
The Sun ◽  
Coronal Emission ◽  
Global Magnetic Field ◽  
Global Modes

The main features concerning the evolution of the large scale photospheric magnetic fields derived from synoptic maps as well as from H-alpha synoptic charts are reviewed. The significance of a variety of observations that indicate the presence of a high latitude component as a counterpart to the sunspot phenomenon at lower latitudes is reviewed. It is argued that these two components describe the global magnetic field on the sun. It is demonstrated that this scenario is able to link many phenomena observed on the sun (coronal emission, ephemeral active regions, geomagnetic activity, torsional oscillations, polar faculae and global modes in the magnetic field pattern) with the global magnetic activity.

scholarly journals A Statistical Study on Force-Freeness of Solar Magnetic Fields in the Photosphere

2013 ◽  
Vol 30 ◽  
Author(s):  
S. Liu ◽  
J. T. Su ◽  
H. Q. Zhang ◽  
Y. Y. Deng ◽  
Y. Gao ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Solar Magnetic Field ◽  
Statistical Study ◽  
Solar Magnetic Fields ◽  
Free Model ◽  
Free Fields ◽  
Heliocentric Coordinates ◽  
Statistical Results ◽  
Calibration Coefficients

AbstractIt is an indisputable fact that solar magnetic fields are force-free in the corona, where force-free fields mean that current and magnetic fields are parallel and there is no Lorentz force in the fields. While the force-free extent of photospheric magnetic fields remains open, in this paper, we give its statistical results. Vector magnetograms (namely, Bx, By, and Bz in heliocentric coordinates) employed are observed by the Solar Magnetic Field Telescope at Huairou Solar Observing Station. We study and calibrate 925 magnetograms calibrated by two sets of calibration coefficients, which indicate the relation between magnetic fields and the strength of the Stokes spectrum and can be calculated either theoretically or empirically. The statistical results show that the majority of active region magnetic fields are not consistent with the force-free model.

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