[P-EM13] [EE] Exploring space plasma processes with Magnetospheric Multiscale (MMS) mission

[PEM13-P04] Currents and associated electron scattering and bouncing near the diffusion region at Earth’s magnetopause

*Benoit Lavraud¹, Yongcun Zhang², Yoann Vernisse¹, Daniel Gershman³, John Dorelli^3,4, Paul Cassak⁵, Jérémy Dargent¹, Craig Pollock³, Barbara Giles³, Nicolas Aunai⁶, Matthew Argall⁷, Levon Avanov³, Alexander Barrie^3,8, James Burch⁹, Michael Chandler³, Li-Jen Chen³, Ian Cohen¹¹, Victoria Coffey¹⁰, Jonathan Eastwood¹², Jan Egedal¹³, Stefan Eriksson¹⁴, Robert Ergun¹⁴, Charlie Farrugia⁷, Stephen Fuselier⁹, Vincent Génot¹, Daniel Graham¹⁵, Elena Grigorenko¹⁶, Hiroshi Hasegawa¹⁷, Christian Jacquey¹, Issaad Kacem¹, Yuri Khotyaintsev¹⁵, Olivier Le Contel⁶, Elisabeth MacDonald³, Werner Magnes¹⁸, Barry Mauk¹¹, Thomas Moore³, Toshifumi Mukai¹⁷, Rumi Nakamura¹⁸, William Paterson³, Emmanuel Penou¹, Tai Phan¹⁹, Amy Rager^3,20, Alessandro Retino⁶, Z. Rong²¹, Christopher Russell²², Yoshifumi Saito¹⁷, Jean-André Sauvaud¹, Stephen Schwartz¹², C. Shen²³, Suzanne Smith⁴ (1.IRAP-CNRS, Toulouse, France, 2.State Key Laboratory of Space Weather, NSSC/CAS, Beijing, China, 3.NASA Goddard Space Flight Center, Greenbelt, MD, 4.University of Maryland, College Park, MD, 5.West Virginia University, WV, 6.Laboratoire de Physique des Plasmas, Palaiseau, France, 7.University of New Hampshire, Durham, NH, 8.Millenium Engineering, Arlington, VA, 9.Southwest Research Institute, San Antonio, TX, 10.NASA Marshall Space Flight Center, Huntsville, AL, 11.Johns Hopkins University Applied Physics Laboratory, Laurel, MD, 12.The Blackett Laboratory, Imperial College, London, UK, 13.University of Wisconsin, Madison, WI, 14.University of Colorado / Laboratory for Atmospheric & Space Physics, Boulder, CO, 15.Swedish Institute of Space Physics, Uppsala, Sweden, 16.Space Research Institute of the Russian Academy of Sciences, Moscow, Russia, 17.Institute of Space and Astronautical Science, JAXA, Sagamihara, Japan, 18.Space Research Institute, Austrian Academy of Sciences, Graz, Austria, 19.Space Sciences Laboratory, Berkeley, CA, 20.Catholic University of America, Washington, DC, 21.Key Laboratory of Earth and Planetary Physics, IGG/CAS, Beijing, China, 22.University of California, Los Angeles, CA, 23.Harbin Institute of Technology, Shenzhen, China)

Keywords:Reconnection, Electrons, Plasma

Based on high-resolution measurements from NASA’s Magnetospheric Multiscale mission, we present the dynamics of electrons associated with current systems observed near the diffusion region of magnetic reconnection at Earth’s magnetopause. Using pitch angle distributions (PAD) and magnetic curvature analysis we demonstrate the occurrence of electron scattering in the curved magnetic field of the diffusion region down to energies of 20 eV. We show that scattering occurs closer to the current sheet as the electron energy decreases. The scattering of inflowing electrons, associated with field-aligned electrostatic potentials and Hall currents, produces a new population of scattered electrons with broader PAD which bounce back and forth in the exhaust. Except at the center of the diffusion region the two populations are collocated and behave adiabatically: the PAD of inflowing electrons focuses inward (towards lower magnetic field), while the bouncing population gradually peaks at 90° away from the center (where it mirrors owing to higher magnetic field and probable field-aligned potentials).