PARA'04 State-of-the-Art
in Scientific Computing
June 20-23, 2004 (Home page)
Updated: 15 February 2004

Particle Acceleration in Multiple Dissipation Regions

Kaspar Arzner
Institute of Astronomy, ETH Zürich,
Switzerland
email: arzner@astro.phys.ethz.ch
and
Loukas Vlahos
Department of Physics, University of Thessaloniki,
Greece

We simulate test particle orbits in a stronlgy turbulent plasma with localized super-Dreicer Ohm electric fields. The system derives from a Gaussian vector potential satisfying the MHD constraints $E/B$ $\sim$ $v_A$ and ${\bf E} \cdot {\bf B}$ = 0 in the absence of resistivity. Weak dependence on time and on one spatial component is imposed, which allows the approximate reduction of the 6-dimensional phase space onto the adiabatic invariants (energy, slow canonical momentum) and provides a qualitative understanding of simulation results in terms of bounded (accelerating) and free (decelerating) stages of a particle's energetic life cycle. It is found that the presence of strong Ohmic fields largely enhances particle acceleration, and can modify it away from standard stochastic acceleration.

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