Electron‐Scale Reconnection in Three‐Dimensional Shock Turbulence

• Published in: Geophysical research letters Vol. 49; no. 15; pp. e2022GL099544 - n/a
• Main Authors: Ng, J., Chen, L.‐J., Bessho, N., Shuster, J., Burkholder, B., Yoo, J.
• Format: Journal Article
• Language: English
• Published: United States John Wiley & Sons, Inc 16.08.2022; American Geophysical Union (AGU)
• Subjects: Current sheets; Electrons; GEOSCIENCES; Kinetic energy; Magnetic field; Magnetic fields; Magnetic flux; Magnetic reconnection; Shock; Simulation; Topology; Turbulence; Upstream
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2022GL099544

Magnetic reconnection has been observed in the transition region of quasi‐parallel shocks. In this work, the particle‐in‐cell method is used to simulate three‐dimensional reconnection in a quasi‐parallel shock. The shock transition region is turbulent, leading to the formation of reconnecting current sheets with various orientations. Two reconnection sites with weak and strong guide fields are studied, and it is shown that reconnection is fast and transient. Reconnection sites are characterized using diagnostics including electron flows and magnetic flux transport. In contrast to two‐dimensional simulations, weak guide field reconnection is realized. Furthermore, the current sheets in these events form in a direction almost perpendicular to those found in two‐dimensional simulations, where the reconnection geometry is constrained. Plain Language Summary Quasi‐parallel shocks are regions where there is a large angle between the shock surface and the upstream magnetic field. Particles reflected from the shock move upstream and excite waves, creating a turbulent environment. This is favorable for the generation of current sheets and a process called magnetic reconnection, in which magnetic energy is converted to kinetic energy with a change in field topology. We use simulations to study reconnection, characterizing reconnection sites and providing comparisons to other simulations and observations. Key Points Turbulent reconnection events in a 3D quasi‐parallel shock simulation are characterized Both strong and weak guide field events are found, consistent with the range of values seen in observations Reconnection sites have different 3D orientations not captured by 2D simulations