Particle acceleration in three-dimensional reconnection regions: A new test particle approach

Magnetic Reconnection is an efficient and fast acceleration mechanism by me ans of direct electric field acceleration parallel to the magnetic field. T hus, acceleration of particles in reconnection regions is a very important topic in plasma astrophysics. In this paper we show that the conventional a nalytical models and numerical test particle investigations can be misleadi ng concerning the energy distribution of the accelerated particles, since t hey oversimplify the electric field structure by the assumption that the fi eld is homogeneous. These investigations of the acceleration of charged tes t particles are extended by considering three-dimensional field configurati ons characterized by localized field-aligned electric fields. Moreover, eff ects of radiative losses are discussed. The comparison between homogeneous and inhomogeneous electric field acceleration in reconnection regions shows dramatic differences concerning both, the maximum particle energy and the form of the energy distribution. (C) 1999 American Institute of Physics. [S 1070-664X(99)01811-X].