Flow Crossover and Parallel Outflow during Collisionless Magnetic Reconnection
Issued Date
2026-02-27
Resource Type
ISSN
00319007
eISSN
10797114
Scopus ID
2-s2.0-105031905363
Journal Title
Physical Review Letters
Volume
136
Issue
8
Rights Holder(s)
SCOPUS
Bibliographic Citation
Physical Review Letters Vol.136 No.8 (2026)
Suggested Citation
Pianpanit T., Malakit K., Prapan P., Ruffolo D., Pongkitiwanichakul P., Suetrong P., Shay M.A., Cassak P.A. Flow Crossover and Parallel Outflow during Collisionless Magnetic Reconnection. Physical Review Letters Vol.136 No.8 (2026). doi:10.1103/whtm-nvkp Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/115662
Title
Flow Crossover and Parallel Outflow during Collisionless Magnetic Reconnection
Corresponding Author(s)
Other Contributor(s)
Abstract
Using particle-in-cell simulations that label ions and electrons according to their initial inflow region, we find that during 2D collisionless magnetic reconnection, the bulk flow of the plasma from each inflow side crosses paths with plasma from the other inflow side and crosses the midplane before being redirected into an outflow jet. This feature, which we term “flow crossover,” implies mechanisms to generate bulk motion in a direction parallel to the magnetic field. We find that ions and electrons undergo different parallel driving mechanisms, leading to different flow crossover patterns. The parallel bulk flow for ions is generated more locally within the ion diffusion region, whereas the parallel bulk flow for electrons is mostly generated outside the electron diffusion region. Consequently, the reconnection outflows are more of a parallel flow than a perpendicular flow, especially for the electron outflow. The flow crossover and the parallel outflow patterns occur not only in symmetric reconnection but also in the more complex scenario of a guide-field asymmetric reconnection, suggesting that it is a general feature of collisionless magnetic reconnection. Because the plasma outflow on one side of the midplane mostly originates from the inflow plasma on the other side, we predict that near an asymmetric reconnection site in a collisionless space plasma, in situ observations across the outflow region could reveal locally reversed gradients in plasma properties. These results are potentially important for quantifying transport across the dayside magnetopause of Earth and other planets and the energy partition in reconnection, including electron and ion heating.