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- Title
Electron Heating Associated With Magnetic Reconnection in Foreshock Waves: Particle‐In‐Cell Simulation Analysis.
- Authors
Wang, Shan; Yang, Yan
- Abstract
Magnetic reconnection occurs in turbulent plasmas like shock transition regions, while its role in energy dissipation therein is not yet clear. We perform a 2D particle‐in‐cell simulation of foreshock waves and study electron heating associated with reconnection. The probability distribution of Te exhibits a shift to higher values near reconnection X‐lines compared to elsewhere. By examining the Te evolution using the superposed epoch analysis, we find that Te is higher in reconnection than in non‐reconnecting current sheets, and Te increases over the ion cyclotron time scale. The heating rate of Te is 10%–40% miVA2, where VA is the average ion Alfvén speed in reconnection regions, which demonstrates the importance of reconnection in heating electrons. We further investigate the bulk electron energization mechanisms by decomposing je · E under guiding center approximations. Around the reconnection onset, E|| dominates the total energization partly contributed by electron holes, and the perpendicular energization is dominated by the magnetization term associated with the gyro‐motion in inhomogeneous fields. The Fermi mechanism contributes negative energization at early time mainly due to Hall effects, and later the outflow in the reconnection plane contributes more dominant positive values. After a couple of ion cyclotron periods from reconnection onset, the Fermi mechanism dominates the energization. A critical factor for initiating reconnection is to drive current sheets to the de‐scale thickness. The reconnection structures can be complicated due to flows originated from the ion‐scale waves, and interactions between multiple reconnection sites. Visualizing such complicated features in simulations may assist future analysis of observation data. Key Points: Statistically electrons are heated in reconnection with a temperature increase at 10%–40% of the available magnetic energy for reconnectionThe electron bulk energization is dominated by E|| around reconnection onset, and is later dominated by Fermi accelerationThe simulation provides guidance for interpreting observations of complicated current sheet structures such as interactions of multiple reconnection sites
- Subjects
MAGNETIC reconnection; DISTRIBUTION (Probability theory); PLASMA turbulence; CURRENT sheets; ELECTRONS
- Publication
Journal of Geophysical Research. Space Physics, 2023, Vol 128, Issue 11, p1
- ISSN
2169-9380
- Publication type
Article
- DOI
10.1029/2023JA031672