Coronal heating and nanoflares: current sheet formation and heating
Abstract
Aims: Solar photospheric footpoint motions can produce strong, localised currents in the corona. A detailed understanding of the formation process and the resulting heating is important in modelling nanoflares, as a mechanism for heating the solar corona.
Methods: A 3D MHD simulation is described in which an initially straight magnetic field is sheared in two directions. Grid resolutions up to 5123 were used and two boundary drivers were considered; one where the boundaries are continuously driven and one where the driving is switched off once a current layer is formed.
Results: For both drivers a twisted current layer is formed. After a long time we see that, when the boundary driving has been switched off, the system relaxes towards a lower energy equilibrium. For the driver which continuously shears the magnetic field we see a repeating cycle of strong current structures forming, fragmenting and decreasing in magnitude and then building up again. Realistic coronal temperatures are obtained.
- Publication:
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Astronomy and Astrophysics
- Pub Date:
- December 2013
- DOI:
- 10.1051/0004-6361/201116652
- Bibcode:
- 2013A&A...560A..89B
- Keywords:
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- magnetohydrodynamics (MHD);
- magnetic reconnection;
- Sun: corona