Particle acceleration and radiation in flaring complex solar active regions modeled by cellular automata

Cyril Dauphin (1, 2) , Nicole Vilmer (1, 2) , Anastasios Anastasiadis (3)

1 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
2 Physique solaire
3 ISARS - Institute for Space Applications and Remote Sensing, National Observatory of Athens

Context: We study the acceleration and radiation of electrons and ions interacting with multiple small-scale dissipation regions resulting from the magnetic energy release process.
Aims: We aim to calculate the distribution functions of the kinetic energy of the particles and the X-ray spectra and gamma-ray fluxes produced by the accelerated particles.
Methods: The evolution of the magnetic energy released in an active region is mimicked by a cellular automaton model based on the concept of self-organized criticality. Each burst of magnetic energy release is associated with a reconnecting current sheet (RCS) in which the particles are accelerated by a direct electric field.
Results: We calculate the energy gain of the particles (ions and electrons) for three different magnetic configurations of the RCS after their interactions with a given number of RCS. We finally compare our results with existing observations.
Conclusions: The results of our simulation can reproduce several properties of the observations such as variable electron and ion energy contents and gamma-ray line ratio. Even if very flat X-ray spectra have been reported in a few events, the X-ray spectra produced in this model are too flat when compared to most X-ray observations.

Domaines: Astrophysique [astro-ph]

Cyril Dauphin, Nicole Vilmer, Anastasios Anastasiadis. Particle acceleration and radiation in flaring complex solar active regions modeled by cellular automata. Astronomy and Astrophysics - A&A, 2007, 468, pp.273-288. ⟨10.1051/0004-6361:20065131⟩. ⟨hal-03786158⟩