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Chen LJ, Wang S, Wilson LB, Schwartz S, Bessho N, Moore T, Gershman D, Giles B, Malaspina D, Wilder FD, Ergun RE, Hesse M, Lai H, Russell C, Strangeway R, Torbert RB, F-Vinas A, Burch J, Lee S, Pollock C, Dorelli J, Paterson W, Ahmadi N, Goodrich K, Lavraud B, Le Contel O, Khotyaintsev YV, Lindqvist PA, Boardsen S, Wei H, Le A, Avanov L. Electron Bulk Acceleration and Thermalization at Earth's Quasiperpendicular Bow Shock. Phys Rev Lett 2018; 120:225101. [PMID: 29906189 DOI: 10.1103/physrevlett.120.225101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/30/2018] [Indexed: 06/08/2023]
Abstract
Electron heating at Earth's quasiperpendicular bow shock has been surmised to be due to the combined effects of a quasistatic electric potential and scattering through wave-particle interaction. Here we report the observation of electron distribution functions indicating a new electron heating process occurring at the leading edge of the shock front. Incident solar wind electrons are accelerated parallel to the magnetic field toward downstream, reaching an electron-ion relative drift speed exceeding the electron thermal speed. The bulk acceleration is associated with an electric field pulse embedded in a whistler-mode wave. The high electron-ion relative drift is relaxed primarily through a nonlinear current-driven instability. The relaxed distributions contain a beam traveling toward the shock as a remnant of the accelerated electrons. Similar distribution functions prevail throughout the shock transition layer, suggesting that the observed acceleration and thermalization is essential to the cross-shock electron heating.
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Affiliation(s)
- L-J Chen
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- Department of Astronomy, University of Maryland, College Park, Maryland 20747, USA
| | - S Wang
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- Department of Astronomy, University of Maryland, College Park, Maryland 20747, USA
| | - L B Wilson
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - S Schwartz
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - N Bessho
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- Department of Astronomy, University of Maryland, College Park, Maryland 20747, USA
| | - T Moore
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - D Gershman
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - B Giles
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - D Malaspina
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - F D Wilder
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - R E Ergun
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - M Hesse
- University of Bergen, Bergen 5020, Norway
| | - H Lai
- University of California, Los Angeles, Los Angeles, California 90095, USA
| | - C Russell
- University of California, Los Angeles, Los Angeles, California 90095, USA
| | - R Strangeway
- University of California, Los Angeles, Los Angeles, California 90095, USA
| | - R B Torbert
- Southwest Research Institute, San Antonio, Texas 78238, USA
| | - A F-Vinas
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - J Burch
- Southwest Research Institute, San Antonio, Texas 78238, USA
| | - S Lee
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - C Pollock
- Denali Scientific, Healy, Alaska 99743, USA
| | - J Dorelli
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - W Paterson
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - N Ahmadi
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - K Goodrich
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - B Lavraud
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse (UPS), CNRS, CNES, Toulouse, 31028 Cedex 4, France
| | - O Le Contel
- Laboratoire de Physique des Plasmas (UMR7648), CNRS/Ecole Polytechnique/Sorbonne Université/Univ. Paris Sud/Observatoire de Paris, Paris, F91128 Palaiseau Cedex, France
| | | | - P-A Lindqvist
- KTH Royal Institute of Technology, Stockholm SE-11428, Sweden
| | - S Boardsen
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- Department of Astronomy, University of Maryland, College Park, Maryland 20747, USA
| | - H Wei
- University of California, Los Angeles, Los Angeles, California 90095, USA
| | - A Le
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - L Avanov
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- Department of Astronomy, University of Maryland, College Park, Maryland 20747, USA
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