Can multi-threaded flux tubes in coronal arcades support a magnetohydrodynamic avalanche?
Abstract
Magnetohydrodynamic (MHD) instabilities allow energy to be released from stressed magnetic fields, commonly modelled in cylindrical flux tubes linking parallel planes, but, more recently, also in curved arcades containing flux tubes with both footpoints in the same photospheric plane. Uncurved cylindrical flux tubes containing multiple individual threads have been shown to be capable of sustaining an MHD avalanche, whereby a single unstable thread can destabilise many. We examine the properties of multi-threaded coronal loops, wherein each thread is created by photospheric driving in a realistic, curved coronal arcade structure (with both footpoints of each thread in the same plane). We use three-dimensional MHD simulations to study the evolution of single- and multi-threaded coronal loops, which become unstable and reconnect, while varying the driving velocity of individual threads. Experiments containing a single thread destabilise in a manner indicative of an ideal MHD instability and consistent with previous examples in the literature. The introduction of additional threads modifies this picture, with aspects of the model geometry and relative driving speeds of individual threads affecting the ability of any thread to destabilise others. In both single- and multi-threaded cases, continuous driving of the remnants of disrupted threads produces secondary, aperiodic bursts of energetic release.
Citation
Threlfall , J , Reid , J & Hood , A W 2021 , ' Can multi-threaded flux tubes in coronal arcades support a magnetohydrodynamic avalanche? ' , Solar Physics , vol. 296 , no. 8 , 120 . https://doi.org/10.1007/s11207-021-01865-7
Publication
Solar Physics
Status
Peer reviewed
ISSN
0038-0938Type
Journal article
Description
Funding: The authors gratefully acknowledge the financial support of STFC through the Consolidated grant, ST/S000402/1, to the University of St Andrews. J. Threlfall is grateful for support from the Division of Games Technology and Mathematics at Abertay University. A.W. Hood acknowledges support from ERC Synergy grant “The Whole Sun” (810218).Collections
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