Some Remarks on the Statics and Dynamics of Magnetic Field Structure Development in Active Regions

1971 ◽  
pp. 201-211
Author(s):  
V. Bumba ◽  
J. Suda
Keyword(s):  
Magnetic Field ◽  
Active Regions ◽  
Field Structure ◽  
Structure Development ◽  
Magnetic Field Structure ◽  
Statics And Dynamics

scholarly journals Some Remarks on the Statics and Dynamics of Magnetic Field Structure Development in Active Regions

1971 ◽  
Vol 43 ◽  
pp. 201-211
Author(s):  
V. Bumba ◽  
J. Suda
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Active Regions ◽  
Field Structure ◽  
Structure Development ◽  
Magnetic Field Structure ◽  
Statics And Dynamics ◽  
Fine Structures

Some comments are given concerning the fine structures in the umbra and penumbra of sunspots and their changes on the basis of high resolution photographs.

A Discussion on the physics of the solar atmosphere - Physics of the solar atmosphere

1976 ◽  
Vol 281 (1304) ◽  
pp. 415-426
Keyword(s):  
Magnetic Field ◽  
Transition Region ◽  
Solar Atmosphere ◽  
Solar Rotation ◽  
Active Regions ◽  
Rotation Velocity ◽  
Coronal Magnetic Field ◽  
Velocity Fields ◽  
Field Structure ◽  
Magnetic Field Structure

A summary is given on recent results on the physics of the quiet solar atmosphere, and active regions. This includes: solar rotation, velocity fields and waves, magnetic field concentration, the transition region, coronal magnetic field structure, and prominences.

scholarly journals An Attempt to Associate Observed Photospheric Motions with the Magnetic Field Structure and Flare Occurrence in an Active Region

1971 ◽  
Vol 43 ◽  
pp. 435-442 ◽  
Author(s):  
M. J. Martres ◽  
I. Soru-Escaut ◽  
J. Rayrole
Keyword(s):  
Magnetic Field ◽  
Active Region ◽  
Empirical Evidence ◽  
Active Regions ◽  
Field Structure ◽  
Magnetic Field Structure ◽  
Abrupt Changes ◽  
The Magnetic Field

We have tried to find empirical evidence for the role of photospheric motions in the building up of the flare productive magnetic patterns in Active Regions.The bright Hα faculae are associated with V∥ structures different from a classical Evershed flow and particularly ‘anomalous’ in the regions and periods of high flare occurrence. The flares observed occurred at ‘crossings’ of the lines V∥ = 0(V ≠ 0) and H∥ = 0 and at places where V∥ = 0 showed abrupt changes of direction. It is suggested that these anomalous V∥ structures are evidence of vortex motions.

scholarly journals Application of the Chromospheric Magnetograph to Active Regions

1971 ◽  
Vol 43 ◽  
pp. 237-242
Author(s):  
H. Zirin
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Solar Surface ◽  
Active Regions ◽  
Field Structure ◽  
Form Complex ◽  
Magnetic Field Structure ◽  
Surface Field ◽  
The Magnetic Field

We show how to determine the magnetic field structure in active regions from the Hα morphology. We also show the role of the EFR (emerging flux region) as a bipolar region of velocity downflow. Finally, we point out that since all new magnetic flux emerges in strictly bipolar form, complex spot groups must result from surface interaction, hence most of the solar surface field may be produced on the surface.

scholarly journals Magnetic Field Structure of the CME Source Region

2001 ◽  
Vol 203 ◽  
pp. 393-395
Author(s):  
Y. Hanaoka
Keyword(s):  
Magnetic Field ◽  
Magnetic Energy ◽  
Source Region ◽  
Three Dimensional ◽  
Active Regions ◽  
Helical Structure ◽  
Field Structure ◽  
Dimensional Structure ◽  
Magnetic Field Structure ◽  
The Magnetic Field

The three-dimensional structure of the magnetic field in the source region of CMEs is the key to understand how the stored magnetic energy eventually causes an eruption. A CME accompanied by a filament eruption on 2000 February 26-27 is particularly a good event to study the three-dimensional magnetic field structure. This event was very well observed with the EIT and LASCO of SOHO and the SXT of Yohkoh, and shows the following clues of the magnetic field structure which caused the CME. (1) The filament had a helical structure before the eruption and it was kept throughout the eruption. (2) The coronal loop structure shows that this event was an eruption of a part of the quadrapolar magnetic field structure consisting of two active regions. In this proceeding, we present a brief overview of the event.

scholarly journals The Magnetic Be Star Sigma Orionis E

1987 ◽  
Vol 92 ◽  
pp. 82-83 ◽  
Author(s):  
C. T. Bolton ◽  
A. W. Fullerton ◽  
D. Bohlender ◽  
J. D. Landstreet ◽  
D. R. Gies
Keyword(s):  
Magnetic Field ◽  
Field Structure ◽  
High Signal ◽  
Rotational Period ◽  
Magnetic Field Structure ◽  
The Past ◽  
Distribution Of Elements ◽  
Be Star ◽  
Hα Emission ◽  
The Magnetic Field

Over the past two years, we have obtained high resolution high signal/noise (S/N) spectra of the magnetic Be star σ Ori E at the Canada-France-Hawaii Telescope and McDonald Observatory. These spectra, which cover the spectral regions 399-417.5 and 440-458.5 nm and the Hα line and have typical S/N>200 and spectral resolution ≃0.02 nm, were obtained at a variety of rotational phases in order to study the magnetic field structure, the distribution of elements in the photosphere, and the effects of the magnetic field on the emission envelope. Our analysis of these spectra confirms, refines and extends the results obtained by Landstreet & Borra (1978), Groote & Hunger (1982 and references therein), and Nakajima (1985).The Hα emission is usually double-peaked, but it undergoes remarkable variations with the 1.19081 d rotational period of the star, which show that the emitting gas is localized into two regions which co-rotate with the star.

scholarly journals Propagation of an MHD Shock in the Vicinity of a Magnetic Neutral Sheet

1980 ◽  
Vol 91 ◽  
pp. 323-326
Author(s):  
D. J. Mullan ◽  
R. S. Steinolfson
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Solar Corona ◽  
Large Scale ◽  
Field Structure ◽  
Neutral Sheet ◽  
Solar Cosmic Rays ◽  
Magnetic Field Structure ◽  
Large Scale Magnetic Field ◽  
Highly Correlated

The acceleration of solar cosmic rays in association with certain solar flares is known to be highly correlated with the propagation of an MHD shock through the solar corona (Svestka, 1976). The spatial structure of the sources of solar cosmic rays will be determined by those regions of the corona which are accessible to the flare-induced shock. The regions to which the flare shock is permitted to propagate are determined by the large scale magnetic field structure in the corona. McIntosh (1972, 1979) has demonstrated that quiescent filaments form a single continuous feature (a “baseball stitch”) around the surface of the sun. It is known that helmet streamers overlie quiescent filaments (Pneuman, 1975), and these helmet streamers contain large magnetic neutral sheets which are oriented essentially radially. Hence the magnetic field structure in the low solar corona is characterized by a large-scale radial neutral sheet which weaves around the entire sun following the “baseball stitch”. There is therefore a high probability that as a shock propagates away from a flare, it will eventually encounter this large neutral sheet.

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