Contribution of patchy reconnection to the ion-to-electron temperature ratio in the Earth's magnetotail

作者：ChuXin Chen,Chih-Ping Wang

摘要：The ion-to-electron temperature ratio is a good indicator of the processes involved in the plasma sheet.Observations have suggested that patchy reconnection and the resulting earthward bursty bulk flows(BBFs)transport may be involved in causing the lower temperature ratios at smaller radial distances during southward IMF periods.In this paper,we estimate theoretically how a patchy magnetic reconnection electric field can accelerate ions and electrons differently.If both ions and electrons are non-adiabatically accelerated only once within each reconnection,the temperature ratio would be preserved.However,when reconnection occurs closer to the Earth where magnetic field lines are shorter,particles mirrored back from the ionosphere can cross the reconnection region more than once within one reconnection;and electrons,moving faster than ions,can have more crossings than do ions,leading to electrons being accelerated more than ions.Thus as particles are transported from tail to the near-Earth by BBFs through multiple reconnection,electrons should be accelerated by the reconnection electric field more times than are ions,which can explain the lower temperature ratios observed closer to the Earth.

发文机构：Chinese Academy of Sciences Key Laboratory of Geospace Environment Department of Atmospheric and Oceanic Sciences

关键词：theion-to-electrontemperatureRATIOplasmasheetpatchymagneticRECONNECTIONnon-adiabaticalacceleration

分类号： P[天文地球]