Particle acceleration in solar flares: linking magnetic energy release with the acceleration process

LUTh, Observatoire de Paris, 92195 Meudon Cedex, France e-mail: cyril.dauphin@obspm.fr

Received: 24 November 2006
Accepted: 21 May 2007

Abstract

Context.Particles accelerated in solar flares draw their energy from the magnetic field. The dissipative scale of the magnetic energy in the solar corona implies that the magnetic energy is transmitted to the particles through a large number of dissipative regions (DR).

Aims.To finally compute the particle energy distribution, we present an approach to linking the magnetic energy release to the acceleration process that occurs in each DR .

Methods.Although not directly observed, the magnetic energy release process is assumed to evolve in an SOC state that leads to the power-law behaviour of the probability distribution function for the energy released in each DR. We consider that most of the accelerated particles leave the acceleration region after one interaction, but we introduce a distribution of the particle acceleration lengths inside each acceleration region.

Results.We calculate the kinetic energy distribution of the accelerated particles. Our model allows us to identify the physical process that determines each part of the particle energy distribution.

Conclusions.As a conclusion, we discuss the limitations of the approach presented in this paper.