Electron Bernstein waves driven by electron crescents near the electron diffusion region

W Y Li; D B Graham; Yu V Khotyaintsev; A Vaivads; M André; K Min; K Liu; B B Tang; C Wang; K Fujimoto; C Norgren; S Toledo-Redondo; P-A Lindqvist; R E Ergun; R B Torbert; A C Rager; J C Dorelli; D J Gershman; B L Giles; B Lavraud; F Plaschke; W Magnes; O Le Contel; C T Russell; J L Burch

doi:10.1038/s41467-019-13920-w

Electron Bernstein waves driven by electron crescents near the electron diffusion region

Nat Commun. 2020 Jan 9;11(1):141. doi: 10.1038/s41467-019-13920-w.

Authors

W Y Li^{1

2

3}, D B Graham⁴, Yu V Khotyaintsev⁵, A Vaivads⁶, M André⁵, K Min⁷, K Liu⁸, B B Tang⁹, C Wang⁹, K Fujimoto¹⁰, C Norgren¹¹, S Toledo-Redondo^{12

13}, P-A Lindqvist⁶, R E Ergun¹⁴, R B Torbert¹⁵, A C Rager^{16

17}, J C Dorelli¹⁷, D J Gershman^{17

18}, B L Giles¹⁷, B Lavraud¹², F Plaschke¹⁹, W Magnes¹⁹, O Le Contel²⁰, C T Russell²¹, J L Burch²²

Affiliations

¹ State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, 100190, Beijing, China. wyli@spaceweather.ac.cn.
² Swedish Institute of Space Physics, SE-75121, Uppsala, Sweden. wyli@spaceweather.ac.cn.
³ State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology, Macau, China. wyli@spaceweather.ac.cn.
⁴ Swedish Institute of Space Physics, SE-75121, Uppsala, Sweden. dgraham@irfu.se.
⁵ Swedish Institute of Space Physics, SE-75121, Uppsala, Sweden.
⁶ Division of Space and Plasma Physics, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, SE-11428, Stockholm, Sweden.
⁷ Department of Astronomy and Space Science, Chungnam National University, Daejeon, 34134, Republic of Korea.
⁸ Department of Earth and Space Sciences, Southern University of Science and Technology, 518055, Shenzhen, China.
⁹ State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, 100190, Beijing, China.
¹⁰ School of Space and Environment, Beihang University, 100191, Beijing, China.
¹¹ Department of Physics and Technology, University of Bergen, 5020, Bergen, Norway.
¹² Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, CNRS, UPS, CNES, 31028, Toulouse, France.
¹³ Department of Electromagnetism and Electronics, University of Murcia, 30003, Murcia, Spain.
¹⁴ Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO, 80303, USA.
¹⁵ Space Science Center, University of New Hampshire, Durham, NH, 03824, USA.
¹⁶ Catholic University of America, Washington, DC, 20064, USA.
¹⁷ NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA.
¹⁸ Department of Astronomy, University of Maryland, College Park, MD, 20742, USA.
¹⁹ Space Research Institute, Austrian Academy of Sciences, 8042, Graz, Austria.
²⁰ Laboratoire de Physique des Plasmas, CNRS/Ecole Polytechnique/Sorbonne Université/Univ. Paris Sud/Observatoire de Paris, 75252, Paris, France.
²¹ Department of Earth and Space Sciences, University of California, Los Angeles, CA, 90095, USA.
²² Southwest Research Institute, San Antonio, TX, 78238, USA.

Abstract

The Magnetospheric Multiscale (MMS) spacecraft encounter an electron diffusion region (EDR) of asymmetric magnetic reconnection at Earth's magnetopause. The EDR is characterized by agyrotropic electron velocity distributions on both sides of the neutral line. Various types of plasma waves are produced by the magnetic reconnection in and near the EDR. Here we report large-amplitude electron Bernstein waves (EBWs) at the electron-scale boundary of the Hall current reversal. The finite gyroradius effect of the outflow electrons generates the crescent-shaped agyrotropic electron distributions, which drive the EBWs. The EBWs propagate toward the central EDR. The amplitude of the EBWs is sufficiently large to thermalize and diffuse electrons around the EDR. The EBWs contribute to the cross-field diffusion of the electron-scale boundary of the Hall current reversal near the EDR.