Coronal energy release by MHD avalanches: Heating mechanisms
File(s)reid_2020a.pdf (6.07 MB)
Published version
Author(s)
Reid, J
Cargill, PJ
Hood, AW
Parnell, CE
Arber, TD
Type
Journal Article
Abstract
The plasma heating associated with an avalanche involving three twisted magnetic threads within a coronal loop is investigated using three-dimensional magnetohydrodynamic simulations. The avalanche is triggered by the kink instability of one thread, with the others being engulfed as a consequence. The heating as a function of both time and location along the strands is evaluated. It is shown to be bursty at all times but to have no preferred spatial location. While there appears to be a level of “background” heating, this is shown to be comprised of individual, small heating events. A comparison between viscous and resistive (Ohmic) heating demonstrates that the strongest heating events are largely associated with the Ohmic heating that arises when the current exceeds a critical value. Viscous heating is largely (but not entirely) associated with smaller events. Ohmic heating dominates viscous heating only at the time of the initial kink instability. It is also demonstrated that a variety of viscous models lead to similar heating rates, suggesting that the system adjusts to dissipate the same amount of energy.
Date Issued
2020-01
Date Acceptance
2019-12-14
Citation
Astronomy and Astrophysics: a European journal, 2020, 633, pp.1-16
ISSN
0004-6361
Publisher
EDP Sciences
Start Page
1
End Page
16
Journal / Book Title
Astronomy and Astrophysics: a European journal
Volume
633
Copyright Statement
© ESO 2020
Identifier
https://www.aanda.org/articles/aa/abs/2020/01/aa37051-19/aa37051-19.html
Subjects
0201 Astronomical and Space Sciences
Astronomy & Astrophysics
Publication Status
Published
Date Publish Online
2020-01-24