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Issue A&A Volume 436, Number 3, June IV 2005 Page(s) 1103 - 1111 Section The Sun DOI 10.1051/0004-6361:20042589

A&A 436, 1103-1111 (2005)
DOI: 10.1051/0004-6361:20042589

Particle acceleration at a three-dimensional reconnection site in the solar corona

S. Dalla and P. K. Browning

School of Physics and Astronomy, University of Manchester, PO Box 88, Manchester M60 1QD, UK

(Received 21 December 2004 / Accepted 9 March 2005)

Abstract
We study test particle trajectories in the vicinity of a three-dimensional (3D) magnetic null point during spine reconnection. Particles are injected into the steady-state non-uniform magnetic and electric fields derived by Priest & Titov (1996), and the equations of motion numerically integrated. We use input parameters typical of the solar corona, for which reconnection has been suggested as the fundamental mechanism responsible for particle acceleration in flare events. We show that substantial acceleration is possible in the 3D spine reconnection configuration, in the strong electric field regime. The energy gain is strongly dependent on the location of injection into the simulation box, as was the case in 2D X-point configurations. In our 3D geometry, we first vary the location of injection within a plane through the spine, and derive an analytical value for the injection angle for which maximum energy gain is achieved. Secondly we vary the azimuthal location of particle injection and show that as one moves away from the plane with maximum electric field magnitude, higher final energies can be achieved, though this requires substantially longer times.

Key words: acceleration of particles -- Sun: flares -- Sun: particle emission

© ESO 2005

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