scholarly journals The Detailed Magnetic Field Structure in the SW Quadrant of M31

1990 ◽  
Vol 140 ◽  
pp. 198-200
Author(s):  
R. Beck ◽  
E.M. Berkhuijsen
Keyword(s):  
Magnetic Field ◽  
Coming Out ◽  
Three Dimensional ◽  
Field Structure ◽  
Magnetic Field Structure ◽  
External Galaxy ◽  
Jeans Instability ◽  
The Magnetic Field

A three-dimensional, arc-like structure in the magnetic field was found coming out of the plane of M31. This structure may be the first Parker-Jeans instability observed in an external galaxy.

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 Three-dimensional Reconstruction of Coronal Plasma Properties from a Single Perspective

2021 ◽  
Vol 922 (2) ◽  
pp. 109
Author(s):  
Joseph Plowman
Keyword(s):  
Magnetic Field ◽  
Preliminary Investigation ◽  
Three Dimensional ◽  
Field Structure ◽  
Coronal Plasma ◽  
Dimensional Structure ◽  
Line Of Sight ◽  
Plasma Properties ◽  
Magnetic Field Structure ◽  
The Magnetic Field

Abstract Much of our understanding of the state of coronal plasmas comes from observations that are optically thin. This means that light travels freely through the corona without being materially affected by it, which allows it to be easily seen through, but also results in a line-of-sight degeneracy that has previously thwarted attempts to recover the three-dimensional structure of the coronal plasma. However, although the corona is disorganized in the line-of-sight direction, it is highly organized in the field-aligned direction. This paper demonstrates how to exploit this organization to resolve the line-of-sight degeneracy in the plasma properties using a suitable magnetic field structure. This allows, for the first time, the two-dimensional optically thin plasma observations to directly drive the three-dimensional plasma reconstruction throughout an entire active region (or larger). A preliminary investigation with a potential field is shown, finding a solution which clearly resembles the real solar data, even with a single perspective. The results indicate that there is ample information in the resulting residuals that can be used to refine the magnetic field structure, suggesting that these residuals can in turn be used to directly constrain the magnetic field extrapolations used in the reconstruction. The paper concludes with a discussion of how these residuals can in turn be used to directly drive the magnetic field extrapolations.

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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