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 Evolution of a Filament/CH/Magnetic Field Complex

1998 ◽  
Vol 167 ◽  
pp. 393-396
Author(s):  
B.A. Ioshpa ◽  
E.I. Mogilevsky ◽  
V.N. Obridko
Keyword(s):  
Magnetic Field ◽  
Active Region ◽  
Magnetic Fields ◽  
Large Scale ◽  
Coronal Holes ◽  
Field Structure ◽  
Potential Approximation ◽  
Magnetic Field Structure ◽  
Single Complex ◽  
The Magnetic Field

AbstractSOHO and YOHKOH images, as well as Hα filtergrams and magnetograms from IZMIRAN have been used to analyze the evolution of the related solar phenomena – filament, active region, and accompanying pair of coronal holes – during six solar rotations, with an emphasis on the events observed during August–September, 1996. The whole complex has been considered against the large–scale magnetic fields calculated under the potential approximation. A peculiar point has been found along the changing filament. It is shown that the phenomena under investigation (filament, active region, and coronal hole) form a single complex connected with the magnetic field structure.

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 What Density of Magnetosheath Sodium Ions Can Provide the Observed Decrease in the Magnetic Field of the “Double Magnetopause” during the First MESSENGER Flyby?

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1168
Author(s):  
Elena Belenkaya ◽  
Ivan Pensionerov
Keyword(s):  
Magnetic Field ◽  
Analytical Approach ◽  
Field Structure ◽  
Sodium Ions ◽  
Plasma Parameters ◽  
Calculation Results ◽  
Magnetizing Current ◽  
The Magnetic Field ◽  
Density Excess

On 14 January 2008, the MESSENGER spacecraft, during its first flyby around Mercury, recorded the magnetic field structure, which was later called the “double magnetopause”. The role of sodium ions penetrating into the Hermean magnetosphere from the magnetosheath in generation of this structure has been discussed since then. The violation of the symmetry of the plasma parameters at the magnetopause is the cause of the magnetizing current generation. Here, we consider whether the change in the density of sodium ions on both sides of the Hermean magnetopause could be the cause of a wide diamagnetic current in the magnetosphere at its dawn-side boundary observed during the first MESSENGER flyby. In the present paper, we propose an analytical approach that made it possible to determine the magnetosheath Na+ density excess providing the best agreement between the calculation results and the observed magnetic field in the double magnetopause.

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.

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