EDP Sciences
Free access
Volume 422, Number 1, July IV 2004
Page(s) 323 - 330
Section The Sun
DOI http://dx.doi.org/10.1051/0004-6361:20035712

A&A 422, 323-330 (2004)
DOI: 10.1051/0004-6361:20035712

Electron acceleration and radiation in evolving complex active regions

A. Anastasiadis1, C. Gontikakis2, N. Vilmer3 and L. Vlahos4

1  National Observatory of Athens, Institute for Space Applications and Remote Sensing, 152 36 Penteli, Greece
2  Research Center for Astronomy and Applied Mathematics, Academy of Athens, Greece
    e-mail: cgontik@cc.uoa.gr
3  LESIA, Observatoire de Paris-Meudon, 92195 Meudon Cedex, France
    e-mail: nicole.vilmer@obspm.fr
4  Department of Physics, University of Thessaloniki, 54124 Thessaloniki, Greece
    e-mail: vlahos@astro.auth.gr

(Received 19 November 2003 / Accepted 26 March 2004)

We present a model for the acceleration and radiation of solar energetic particles (electrons) in evolving complex active regions. The spatio - temporal evolution of active regions is calculated using a cellular automaton model, based on self-organized criticality. The acceleration of electrons is due to the presence of randomly placed, localized electric fields produced by the energy release process, simulated by the cellular automaton model. We calculate the resulting kinetic energy distributions of the particles and their emitted X-ray radiation spectra using the thick target approximation, and we perform a parametric study with respect to number of electric fields present and thermal temperature of the injected distribution. Finally, comparing our results with the existing observations, we find that they are in a good agreement with the observed X-ray spectra in the energy range 100-1000 keV.

Key words: Sun: flares -- Sun: X-rays, gamma rays -- acceleration of particles

Offprint request: A. Anastasiadis, anastasi@space.noa.gr

© ESO 2004