Two-stage electron acceleration by 3D collisionless guide field magnetic reconnection

Abstract

We report a newly found two-stage mechanism of electron acceleration near X-lines of 3D collisionless guide-field magnetic reconnection in the non-relativistic regime typical, e.g., for stellar coronae. We found that after electrons are first pre-accelerated during the linear growth of reconnection, they become additionally accelerated in the course of the nonlinear stage of 3D guide-field magnetic reconnection. This additional acceleration is due to the filamentation of electric and magnetic fields caused by streaming instabilities. In addition to enhanced parallel electric fields, the filamentation leads to additional curvature-driven electron acceleration in the guide-field direction. As a result, part of the the accelerated electron spectra becomes a power law with a spectral index of $\sim -1.6$ near the X-line. This second stage of acceleration due to nonlinear reconnection is relevant for the production of energetic electrons in, e.g., thin current sheets of stellar coronae.

15 pages. 11 figures. Revised version. Published in The Astrophysical Journal

References in corpus (8)

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• The role of three-dimensional transport in driving enhanced electron acceleration during magnetic reconnection
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Cited by in corpus (8)

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• Preferential acceleration of heavy ions in magnetic reconnection: Hybrid-kinetic simulations with electron inertia
• Electron-to-ion bulk speed ratio as a parameter reflecting the occurrence of strong electron-dominated current sheets in the solar wind
• Nonthermal electron velocity distribution functions due to 3D kinetic magnetic reconnection for solar coronal plasma conditions
• Characterizing Velocity-Space Signatures of Electron Energization in Large-Guide-Field Collisionless Magnetic Reconnection