Heating of braided coronal loops

TY - JOUR

T1 - Heating of braided coronal loops

A1 - Wilmot-Smith,A. L.

A1 - Pontin,D. I.

A1 - Yeates,A. R.

A1 - Hornig,G.

AU - Wilmot-Smith,A. L.

AU - Pontin,D. I.

AU - Yeates,A. R.

AU - Hornig,G.

PY - 2011/12

Y1 - 2011/12

N2 - <p>Aims. We investigate the relaxation of braided magnetic loops in order to find out how the type of braiding via footpoint motions affects resultant heating of the loop.</p><p>Methods. Two magnetic loops, braided in different ways, are used as initial conditions in resistive MHD simulations and their subsequent evolution is studied.</p><p>Results. The fields both undergo a resistive relaxation in which current sheets form and fragment and the system evolves towards a state of lower energy. In one case this relaxation is very efficient with current sheets filling the volume and homogeneous heating of the loop occurring. In the other case fewer current sheets develop, less magnetic energy is released in the process and a patchy heating of the loop results. The two cases, although very similar in their setup, can be distinguished by the mixing properties of the photospheric driver. The mixing can be measured by the topological entropy of the plasma flow, an observable quantity.</p>

AB - <p>Aims. We investigate the relaxation of braided magnetic loops in order to find out how the type of braiding via footpoint motions affects resultant heating of the loop.</p><p>Methods. Two magnetic loops, braided in different ways, are used as initial conditions in resistive MHD simulations and their subsequent evolution is studied.</p><p>Results. The fields both undergo a resistive relaxation in which current sheets form and fragment and the system evolves towards a state of lower energy. In one case this relaxation is very efficient with current sheets filling the volume and homogeneous heating of the loop occurring. In the other case fewer current sheets develop, less magnetic energy is released in the process and a patchy heating of the loop results. The two cases, although very similar in their setup, can be distinguished by the mixing properties of the photospheric driver. The mixing can be measured by the topological entropy of the plasma flow, an observable quantity.</p>

KW - Magnetic fields

KW - Magnetic reconnection

KW - Magnetohydrodynamics (MHD)

KW - Plasmas

KW - Sun: corona

KW - Sun: magnetic topology

KW - Active region core

KW - Magnetic fields

KW - Solar corona

KW - Footpoint motions

KW - 3D reconnection

KW - Current sheets

KW - Relaxation

KW - Dynamics

U2 - 10.1051/0004-6361/201117942

DO - 10.1051/0004-6361/201117942

M1 - Article

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

VL - 536

SP - -

ER -