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The triggering of MHD instabilities through photospheric footpoint motions

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Gerrard, C. L., Arber, T. D. and Hood, Alan W.. (2002) The triggering of MHD instabilities through photospheric footpoint motions. Astronomy & Astrophysics, Vol.387 (No.2). pp. 687-699. ISSN 0004-6361

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Official URL: http://dx.doi.org/10.1051/0004-6361:20020491

Abstract

The results of 3D numerical simulations modelling the twisting of a coronal loop due to photospheric vortex motions are presented. The simulations are carried out using an initial purely axial field and an initial equilibrium configuration with twist, . The non-linear and resistive evolutions of the instability are followed. The magnetic field is twisted by the boundary motions into a loop which initially has boundary layers near the photospheric boundaries as has been suggested by previous work. The boundary motions increase the twist in the loop until it becomes unstable. For both cases the boundary twisting triggers the kink instability. In both cases a helical current structure wraps itself around the kinked central current. This current scales linearly with grid resolution indicating current sheet formation. For the cases studied 35-40% of the free magnetic energy is released. This is sufficient to explain the energy released in a compact loop flare.

Item Type:

Journal Article

Subjects:

Q Science > QB Astronomy

Divisions:

Faculty of Science > Physics

Library of Congress Subject Headings (LCSH):

Sun -- Corona, Sun -- Loop prominences, Magnetohydrodynamics, Solar magnetic fields

Journal or Publication Title:

Astronomy & Astrophysics

Publisher:

EDP Sciences

ISSN:

0004-6361

Official Date:

May 2002

Dates:

Date	Event
May 2002	Published

Volume:

Vol.387

Number:

No.2

Page Range:

pp. 687-699

Identification Number:

10.1051/0004-6361:20020491

Status:

Peer Reviewed

Access rights to Published version:

Open Access

Funder:

Higher Education Funding Council for England (HEFCE), Scottish Higher Education Funding Council (SHEFC)

References:

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