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arXiv · 1201.0837

Stochastic Particle Acceleration in Multiple Magnetic Islands during Reconnection

Masahiro Hoshino
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Abstract

A nonthermal particle acceleration mechanism involving the interaction of a charged particle with multiple magnetic islands is proposed. The original Fermi acceleration model, which assumes randomly distributed magnetic clouds moving at random velocity $V_c$ in the interstellar medium, is known to be of second-order acceleration of $O(V_c/c)^2$ owing to the combination of head-on and head-tail collisions. In this letter, we reconsider the original Fermi model by introducing multiple magnetic islands during reconnect ion instead of magnetic clouds. We discuss that the energetic particles have a tendency to be distributed outside the magnetic islands, and they mainly interact with reconnection outflow jets. As a result, the acceleration efficiency becomes first-order of $O(V_A/c)$, where $V_A$ and $c$ are the Alfv\'en velocity and the speed of light, respectively.

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Masahiro Hoshino. 2012-01-04. Stochastic Particle Acceleration in Multiple Magnetic Islands during Reconnection. https://doi.org/10.1103/physrevlett.108.135003

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