The role of initial magnetic field structure in the launching of protostellar jets

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.

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Application of the Chromospheric Magnetograph to Active Regions

Symposium - International Astronomical Union ◽

10.1017/s0074180900022634 ◽

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.

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Prompt arrival of solar energetic particles from Far Eastern Events: The role of large-scale interplanetary magnetic field structure

Journal of Geophysical Research Atmospheres ◽

10.1029/91ja00379 ◽

1991 ◽

Vol 96 (A5) ◽

pp. 7853 ◽

Cited By ~ 48

Author(s):

I. G. Richardson ◽

H. V. Cane ◽

T. T. von Rosenvinge

Keyword(s):

Magnetic Field ◽

Interplanetary Magnetic Field ◽

Large Scale ◽

Energetic Particles ◽

Solar Energetic Particles ◽

Field Structure ◽

Magnetic Field Structure ◽

Far Eastern

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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 ◽

10.3390/sym13071168 ◽

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.

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The Magnetic Be Star Sigma Orionis E

International Astronomical Union Colloquium ◽

10.1017/s0252921100116057 ◽

1987 ◽

Vol 92 ◽

pp. 82-83 ◽

Cited By ~ 3

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

Symposium - International Astronomical Union ◽

10.1017/s0074180900067802 ◽

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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