Whistler Driven Magnetic Reconnection at the Dayside Magnetopause

Thursday, 13 July 2017: 08:30
Furong Room (Cynn Hotel)
James L Burch1, Robert Ergun2, Paul Cassak3, James Webster4, Roy B Torbert5, Barbara L Giles6, John Dorelli6, Amy Catherine Rager7, Kyoung-Joo Hwang8, Tai Phan9, Kevin Genestreti10, Robert Allen1, Li-Jen Chen6, Shan Wang11, Daniel J Gershman11, Olivier Le Contel12, Christopher T Russell13, Robert J Strangeway14, Frederick D Wilder15, Daniel Bruce Graham16, Michael Hesse17, James Frederick Drake11, Mark Swisdak18, Michael Shay19, Per-Arne Lindqvist20, Craig J Pollock21, Richard Eugene Denton22 and David Newman15, (1)Southwest Research Institute, San Antonio, TX, United States, (2)Univ Colorado, Boulder, CO, United States, (3)West Virginia University, Department of Physics and Astronomy, Morgantown, WV, United States, (4)Rice University, Houston, TX, United States, (5)University of New Hampshire Main Campus, Durham, NH, United States, (6)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (7)Catholic University of America, Physics, Washington, DC, United States, (8)NASA Goddard Space Flight Center, Heliophysics Science Division, Greenbelt, MD, United States, (9)University of California Berkeley, Berkeley, CA, United States, (10)Austrian Academy of Sciences, Vienna, Austria, (11)University of Maryland College Park, College Park, MD, United States, (12)Laboratoire de Physique des Plasmas (UMR7648), CNRS/Ecole Polytechnique/UPMC/Univ. Paris Sud/Obs. de Paris, Paris, France, (13)University of California Los Angeles, Earth, Planetary, and Space Sciences, Los Angeles, CA, United States, (14)University of California Los Angeles, IGPP/EPSS, Los Angeles, CA, United States, (15)University of Colorado at Boulder, Boulder, CO, United States, (16)IRF Swedish Institute of Space Physics Uppsala, Uppsala, Sweden, (17)University of Bergen, Bergen, Norway, (18)University of Maryland, College Park, MD, United States, (19)University of Delaware, Newark, DE, United States, (20)KTH Royal Institute of Technology, Stockholm, Sweden, (21)NASA Goddard Space Flight Center, Heliophysics Sci. Div., Greenbelt, MD, United States, (22)Dartmouth College, Hanover, NH, United States
Abstract:
Magnetic reconnection is a plasma process by which magnetic fields from different sources interconnect, allowing plasma and momentum to be transferred across their boundaries. Reconnection is important for plasmas in near and deep space and in the laboratory. The process leading to reconnection involves the explosive conversion of magnetic energy to heat and kinetic energy of charged particles, as evidenced by solar flares and terrestrial aurora. Data from the NASA Magnetospheric Multiscale (MMS) mission have so far identified the electron populations and electric fields involved in reconnection at the dayside boundary of the Earth's magnetosphere (the magnetopause) where reconnection is highly asymmetric because of the more intense magnetic field and lower plasma density on the inner, magnetosphere side of the boundary as compared to the outer, magnetosheath side. Further information on details of the electric and magnetic fields and plasma waves in the reconnection region are, however, needed to identify the physical processes at work. Here we show with the highest-resolution data available from MMS that the reconnection process is driven by large electric-field components of a confined oblique electrostatic whistler wave, which is very different from the small, widespread, quasi-static electric fields that had been thought to drive reconnection. These large whistler electric fields are shown to dissipate magnetic energy and to correlate directly with the transition from closed magnetospheric field lines to open field lines extending from the magnetosphere into the magnetosheath. This change in magnetic topology is direct evidence of the breaking and reconnection of magnetic field lines. These measurements require significant modifications to current models of the reconnection process.
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