loading page

Off-diagonal Ion Pressure Term Associated with Hall Fields in Collisionless Magnetic Reconnection
  • +6
  • Kailai Wang,
  • Lei Dai,
  • Shan Wang,
  • Yong Ren,
  • Minghui Zhu,
  • Chi Wang,
  • Benoit Lavraud,
  • Christopher Philippe Escoubet,
  • James L Burch
Kailai Wang
National Space Science Center Chinese Academy of Sciences
Author Profile
Lei Dai
National Space Science Center Chinese Academy of Sciences

Corresponding Author:[email protected]

Author Profile
Shan Wang
Peking University
Author Profile
Yong Ren
State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences
Author Profile
Minghui Zhu
National Space Science Center, Chinese Academy of Sciences
Author Profile
Chi Wang
National Space Science Center, Chinese Academy of Sciences
Author Profile
Benoit Lavraud
Laboratoire d'astrophysique de Bordeaux
Author Profile
Christopher Philippe Escoubet
ESA / ESTEC
Author Profile
James L Burch
Southwest Research Institute
Author Profile

Abstract

Magnetic reconnection converts magnetic energy into particle energy, with ion outflows being a prominent manifestation, particularly in geospace. Hall fields are indicators of rapid energy conversion in collisionless magnetic reconnection, yet the associated ion processes and signatures are not fully understood. Here, we analyze in-situ data and simulations to identify a distinct signature in the off-diagonal component of the ion pressure tensor. This signature displays a bipolar reversal that correlates with ion outflows across the reconnection X-line. The bipolar signal arises from a distorted velocity distribution during ion acceleration. Initially, Hall electric fields induce dawnward ion motion, which is followed by enhanced ion acceleration due to reconnection electric fields during cyclotron motion around the reconnected magnetic field. This interaction distorts the velocity distribution, producing the observed bipolar signals. The off-diagonal component of the ion pressure tensor reflects increased ion acceleration and energy conversion due to Hall electric fields.