Birn, J., Battaglia, M., Fletcher, L. , Hesse, M. and Neukirch, T. (2017) Can substorm particle acceleration be applied to solar flares? Astrophysical Journal, 848(2), 116. (doi: 10.3847/1538-4357/aa8ad4)
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Abstract
Using test particle studies in the electromagnetic fields of three-dimensional magnetohydrodynamic (MHD) simulations of magnetic reconnection, we study the energization of charged particles in the context of the standard two-ribbon flare picture in analogy to the standard magnetospheric substorm paradigm. In particular we investigate the effects of the collapsing field ("collapsing magnetic trap") below a reconnection site, which has been demonstrated to be the major acceleration mechanism causing energetic particle acceleration and injections observed in Earth's magnetotail associated with substorms and other impulsive events. We contrast an initially force-free, high shear, field (low beta) with low and moderate shear, finite-pressure (high beta) arcade structures, where beta represents the ratio between gas (plasma) and magnetic pressure. We demonstrate that the energization affects large numbers of particles but the acceleration is modest in the presence of a significant shear field. Without incorporating loss mechanisms, the effect on particles at different energies is similar, akin to adiabatic heating, and thus not a likely mechanism to generate a power law tail onto a (heated or not heated) Maxwellian velocity distribution.
| Item Type: | Articles |
|---|---|
| Keywords: | MHD - sun, corona - sun, magnetic fields, solar flares, particle acceleration. |
| Status: | Published |
| Refereed: | Yes |
| Glasgow Author(s) Enlighten ID: | Fletcher, Professor Lyndsay and Battaglia, Dr Marina |
| Authors: | Birn, J., Battaglia, M., Fletcher, L., Hesse, M., and Neukirch, T. |
| Subjects: | Q Science > QB Astronomy Q Science > QC Physics |
| College/School: | College of Science and Engineering > School of Physics and Astronomy |
| Research Group: | Astronomy and Astrophysics |
| Journal Name: | Astrophysical Journal |
| Journal Abbr.: | ApJ |
| Publisher: | IOP |
| ISSN: | 0004-637X |
| ISSN (Online): | 1538-4357 |
| Copyright Holders: | Copyright © 2017 American Astronomical Society |
| First Published: | First published in Astrophysical Journal 848(2):116 |
| Publisher Policy: | Reproduced under a Creative Commons License |
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