scholarly journals The Coronal Global Evolutionary Model: Using HMI Vector Magnetogram and Doppler Data to Model the Buildup of Free Magnetic Energy in the Solar Corona

Space Weather ◽  
2015 ◽  
Vol 13 (6) ◽  
pp. 369-373 ◽  
Author(s):  
G. H. Fisher ◽  
W. P. Abbett ◽  
D. J. Bercik ◽  
M. D. Kazachenko ◽  
B. J. Lynch ◽  
...  
Keyword(s):  
Solar Corona ◽  
Magnetic Energy ◽  
Evolutionary Model ◽  
Doppler Data ◽  
Free Magnetic Energy

scholarly journals Storing free magnetic energy in the solar corona

2016 ◽  
Vol 82 (4) ◽  
Author(s):  
G. Vekstein
Keyword(s):  
Solar Corona ◽  
Solar Flares ◽  
Magnetic Energy ◽  
Solar Physics ◽  
Interested Reader ◽  
Convective Flows ◽  
Free Magnetic Energy ◽  
Wide Readership ◽  
Magnetic Arcade

This article presents a mini-tutorial aimed at a wide readership not familiar with the field of solar plasma physics. The exposition is centred around the issue of excess/free magnetic energy stored in the solar corona. A general consideration is followed with a particular example of coronal magnetic arcade, where free magnetic energy builds up by photospheric convective flows. In the context of solar physics the major task is to explain how this free energy can be released quickly enough to match what is observed in coronal explosive events such as solar flares. Therefore, in the last section of the paper we discuss briefly a possible role of magnetic reconnection in these processes. This is done in quite simple qualitative physical terms, so that an interested reader can follow it up in more detail with help of the provided references.

TEMPORAL EVOLUTION OF FREE MAGNETIC ENERGY ASSOCIATED WITH FOUR X-CLASS FLARES

2009 ◽  
Vol 696 (1) ◽  
pp. 84-90 ◽  
Author(s):  
Ju Jing ◽  
P. F. Chen ◽  
Thomas Wiegelmann ◽  
Yan Xu ◽  
Sung-Hong Park ◽  
...  
Keyword(s):  
Temporal Evolution ◽  
Magnetic Energy ◽  
Free Magnetic Energy

scholarly journals A solar tornado caused by flares

2013 ◽  
Vol 8 (S300) ◽  
pp. 235-238
Author(s):  
N. K. Panesar ◽  
D. E. Innes ◽  
S. K. Tiwari ◽  
B. C. Low
Keyword(s):  
Active Region ◽  
Magnetic Energy ◽  
Magnetic Pressure ◽  
The Sun ◽  
Active Region Noaa ◽  
Quiescent Prominence ◽  
Triggering Mechanism ◽  
Free Magnetic Energy ◽  
Cavity System ◽  
Region Noaa

AbstractAn enormous solar tornado was observed by SDO/AIA on 25 September 2011. It was mainly associated with a quiescent prominence with an overlying coronal cavity. We investigate the triggering mechanism of the solar tornado by using the data from two instruments: SDO/AIA and STEREO-A/EUVI, covering the Sun from two directions. The tornado appeared near to the active region NOAA 11303 that produced three flares. The flares directly influenced the prominence-cavity system. The release of free magnetic energy from the active region by flares resulted in the contraction of the active region field. The cavity, owing to its superior magnetic pressure, expanded to fill this vacated space in the corona. We propose that the tornado developed on the top of the prominence due to the expansion of the prominence-cavity system.

scholarly journals Evolution of Plasma Composition in an Eruptive Flux Rope

2022 ◽  
Vol 924 (1) ◽  
pp. 17
Author(s):  
D. Baker ◽  
L. M. Green ◽  
D. H. Brooks ◽  
P. Démoulin ◽  
L. van Driel-Gesztelyi ◽  
...  
Keyword(s):  
Magnetic Energy ◽  
Flux Rope ◽  
Plasma Composition ◽  
Imaging Spectrometer ◽  
Polarity Inversion ◽  
Magnetic Flux Ropes ◽  
Flux Ropes ◽  
Free Magnetic Energy ◽  
Polarity Inversion Line ◽  
Euv Imaging

Abstract Magnetic flux ropes are bundles of twisted magnetic field enveloping a central axis. They harbor free magnetic energy and can be progenitors of coronal mass ejections (CMEs). However, identifying flux ropes on the Sun can be challenging. One of the key coronal observables that has been shown to indicate the presence of a flux rope is a peculiar bright coronal structure called a sigmoid. In this work, we show Hinode EUV Imaging Spectrometer observations of sigmoidal active region (AR) 10977. We analyze the coronal plasma composition in the AR and its evolution as a sigmoid (flux rope) forms and erupts as a CME. Plasma with photospheric composition was observed in coronal loops close to the main polarity inversion line during episodes of significant flux cancellation, suggestive of the injection of photospheric plasma into these loops driven by photospheric flux cancellation. Concurrently, the increasingly sheared core field contained plasma with coronal composition. As flux cancellation decreased and a sigmoid/flux rope formed, the plasma evolved to an intermediate composition in between photospheric and typical AR coronal compositions. Finally, the flux rope contained predominantly photospheric plasma during and after a failed eruption preceding the CME. Hence, plasma composition observations of AR 10977 strongly support models of flux rope formation by photospheric flux cancellation forcing magnetic reconnection first at the photospheric level then at the coronal level.

scholarly journals Difference of source regions between fast and slow coronal mass ejections

2019 ◽  
Vol 36 ◽  
Author(s):  
B. Filippov
Keyword(s):  
Magnetic Field ◽  
Coronal Mass Ejections ◽  
Solar Flares ◽  
Magnetic Energy ◽  
Active Regions ◽  
Coronal Magnetic Field ◽  
Source Regions ◽  
Free Magnetic Energy ◽  
The Difference ◽  
Sunspot Groups

Abstract Coronal mass ejections (CMEs) are tightly related to filament eruptions and usually are their continuation in the upper solar corona. It is common practice to divide all observed CMEs into fast and slow ones. Fast CMEs usually follow eruptive events in active regions near big sunspot groups and associated with major solar flares. Slow CMEs are more related to eruptions of quiescent prominences located far from active regions. We analyse 10 eruptive events with particular attention to the events on 2013 September 29 and on 2016 January 26, one of which was associated with a fast CME, while another was followed by a slow CME. We estimated the initial store of free magnetic energy in the two regions and show the resemblance of pre-eruptive situations. The difference of late behaviour of the two eruptive prominences is a consequence of the different structure of magnetic field above the filaments. We estimated this structure on the basis of potential magnetic field calculations. Analysis of other eight events confirmed that all fast CMEs originate in regions with rapidly changing with height value and direction of coronal magnetic field.

scholarly journals Storage and Release of Magnetic Energy in a Force-Free Field

1990 ◽  
Vol 142 ◽  
pp. 313-318
Author(s):  
J.J. Aly
Keyword(s):  
Half Space ◽  
Magnetic Energy ◽  
Free Field ◽  
Current Sheets ◽  
Reconnection Process ◽  
Free Magnetic Energy ◽  
Force Free Field

For a 3D force-free field occupying a half-space D = {z > 0}, we discuss: i) the storage of free magnetic energy when the field evolves quasi-statically as a consequence of motions imposed to its footpoints on the plane {z = 0}; ii) the release of this energy during a reconnection process implying a rearrangement of the lines which is either local, occuring in the neighbourhood of spontaneously formed current sheets, or global, occuring in an explosive flare-like way.

scholarly journals PIC Simulations of Excited Waves in the Plasmoid Instability

2022 ◽  
Vol 8 ◽  
Author(s):  
Mahdi Shahraki Pour ◽  
Mahboub Hosseinpour
Keyword(s):  
Particle Acceleration ◽  
Kinetic Energy ◽  
Solar Corona ◽  
Current Sheet ◽  
Electromagnetic Waves ◽  
Magnetic Energy ◽  
Particle In Cell ◽  
Guide Field ◽  
Collisionless Regime ◽  
Accelerated Particles

Fragmentation of an elongated current sheet into many reconnection X-points, and therefore multiple plasmoids, occurs frequently in the solar corona. This speeds up the release of solar magnetic energy in the form of thermal and kinetic energy. Moreover, due to the presence of multiple reconnection X-points, the particle acceleration is more efficient in terms of the number of accelerated particles. This type of instability called “plasmoid instability” is accompanied with the excitation of some electrostatic/electromagnetic waves. We carried out 2D particle-in-cell simulations of this instability in the collisionless regime, with the presence of non-uniform magnetic guide field to investigate the nature of excited waves. It is shown that the nature and properties of waves excited inside and outside the current sheet are different. While the outside perturbations are transient, the inside ones are long-lived, and are directly affected by the plasmoid instability process.

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