SM41I-03
MMS Observations of Parallel Electric Fields
Thursday, 17 December 2015: 08:30
2018 (Moscone West)
Robert Ergun1, Katherine Goodrich2, Frederick D Wilder2, Andrew Paul Sturner3, Justin Holmes3, Julia E Stawarz3, David Malaspina4, Maria Usanova2, Roy B Torbert5, Per-Arne Lindqvist6, Yuri V Khotyaintsev7, James L Burch8, Robert J Strangeway9, Christopher T Russell10, Craig J Pollock11, Barbara L Giles12, Michael Hesse12, Martin V Goldman2, James Frederick Drake13, Tai Phan14 and Rumi Nakamura15, (1)Univ Colorado, Boulder, CO, United States, (2)University of Colorado at Boulder, Boulder, CO, United States, (3)Laboratory for Atmospheric and Space Physics, Boulder, CO, United States, (4)University of Colorado, Boulder, Laboratory for Atmospheric and Space Physics, Boulder, CO, United States, (5)University of New Hampshire Main Campus, Durham, NH, United States, (6)KTH Royal Institute of Technology, Stockholm, Sweden, (7)IRF Swedish Institute of Space Physics Uppsala, Uppsala, Sweden, (8)Southwest Research Institute, San Antonio, TX, United States, (9)University of California Los Angeles, Los Angeles, CA, United States, (10)University of California Los Angeles, IGPP/EPSS, Los Angeles, CA, United States, (11)NASA Goddard Space Flight Center, Heliophysics Sci. Div., Greenbelt, MD, United States, (12)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (13)University of Maryland College Park, College Park, MD, United States, (14)University of California Berkeley, Berkeley, CA, United States, (15)Austrian Academy of Sciences, Vienna, Austria
Abstract:
Parallel electric fields are a necessary condition for magnetic reconnection with non-zero guide field and are ultimately accountable for topological reconfiguration of a magnetic field. Parallel electric fields also play a strong role in charged particle acceleration and turbulence. The Magnetospheric Multiscale (MMS) mission targets these three universal plasma processes. The MMS satellites have an accurate three-dimensional electric field measurement, which can identify parallel electric fields as low as 1 mV/m at four adjacent locations. We present preliminary observations of parallel electric fields from MMS and provide an early interpretation of their impact on magnetic reconnection, in particular, where the topological change occurs. We also examine the role of parallel electric fields in particle acceleration. Direct particle acceleration by parallel electric fields is well established in the auroral region. Observations of double layers in by the Van Allan Probes suggest that acceleration by parallel electric fields may be significant in energizing some populations of the radiation belts. THEMIS observations also indicate that some of the largest parallel electric fields are found in regions of strong field-aligned currents associated with turbulence, suggesting a highly non-linear dissipation mechanism. We discuss how the MMS observations extend our understanding of the role of parallel electric fields in some of the most critical processes in the magnetosphere.
