Signatures of Magnetic Reconnection in 3D Electric Field MMS Data: Elucidating Particle Energization Throughout the Diffusion Region
Thursday, October 1, 2015
Jason R Shuster1, Matthew R Argall1, Guanlai Li1, Roy B Torbert1,2, Li-Jen Chen3, Robert E Ergun4, Per-Arne Lindqvist5, Goran Tage Marklund5, Yuri V Khotyaintsev6, Christopher T Russell7, Werner Magnes8, Olivier Le Contel9, Hans Vaith1, Craig J Pollock3 and Barbara L Giles3, (1)University of New Hampshire Main Campus, Durham, NH, United States, (2)Southwest Research Institute San Antonio, San Antonio, TX, United States, (3)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (4)University of Colorado, Boulder, CO, United States, (5)KTH Royal Institute of Technology, Stockholm, Sweden, (6)IRF Swedish Institute of Space Physics Uppsala, Uppsala, Sweden, (7)University of California Los Angeles, Los Angeles, CA, United States, (8)Space Research Institute, Austrian Academy of Sciences, Graz, Austria, (9)Laboratoire de Physique des Plasmas (UMR7648), CNRS/Ecole Polytechnique/UPMC/Univ. Paris Sud/Obs. de Paris, Paris, France
Abstract:
The unprecedented time resolution of the 3D electric field measurements made by the FIELDS suite [Torbert et al., 2014] onboard the MMS spacecraft motivates a comprehensive study of the electric field signatures of magnetic reconnection and their implications for particle energization. From previous observational studies using Cluster electric field data (where the assumption E⋅B = 0 is typically made), DC electric field reversals combined with unmagnetized electron measurements from EDI can be used together to identify electron current sheet crossings [Chen et al., 2008]. Studies clearly identifying the electron diffusion region using Cluster data are rare because of limited temporal and spatial resolution capabilities. The three-axis electric field measurements from the spin-plane and axial double probes (SDP and ADP), combined with high time resolution ambient electron flux (30 milliseconds) from EDI, enable the resolution of electron-scale reconnection structures. At the finest electron scales, fully kinetic particle-in-cell simulations predict the existence of a bipolar inversion electric field structure embedded in the Hall electric field that extends throughout the entire length of the electron diffusion region [Chen et al., 2011]. Strongly enhanced bipolar electric fields can also be signatures of secondary magnetic islands generated by thin electron current layers [Chen et al., 2012]. Previous studies have proposed a large-scale parallel electric field model supported by observations of highly anisotropic electron velocity distributions to explain energization in symmetric reconnection [e.g. Egedal et al., 2012]. Here, we present our first efforts to organize the initial MMS electric field measurements in and around the diffusion region to address the validity of these previous predictions.
