Observations of Counterstreaming Electron Fluxes in the Nightside Magnetosphere: First Results from MMS/FPI Data.
Thursday, October 1, 2015
Levon A Avanov1, Craig J Pollock1, Ulrik Gliese1, George V Khazanov2, John Dorelli1, Alexander Barrie3, Daniel J Gershman4, Barbara L Giles1, Matthew P Holland1, Chad Salo5, Charles Dickson6, Arthur D Jacques1, Roy B Torbert7, Christopher T Russell8 and Robert J Strangeway9, (1)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (2)NASA Goddard Space Flight Center, Heliophysics Sci. Div., Greenbelt, MD, United States, (3)Millenium Engineering and Integration Company, Arlington, VA, United States, (4)NASA/GSFC, Greenbelt, MD, United States, (5)Stellar Solutions, Palo Alto, CA, United States, (6)AS and D, Inc., Beltsville, MD, United States, (7)Univ New Hampshire, Durham, NH, United States, (8)University of California Los Angeles, Los Angeles, CA, United States, (9)University of California Los Angeles, IGPP/EPSS, Los Angeles, CA, United States
Abstract:
We present some first results from the Fast Plasma Investigation (FPI) onboard the Magnetospheric Multiscale mission (MMS). During commissioning, FPI acquired high-time resolution data (30 ms for electrons and 150 ms for ions) in the vicinity of spacecraft apogee ~12 RE at magnetic local times between 0300 and 2200 hours. Electron distribution functions revealed counterstreaming electron populations with energies of ~100 eV. Observations of two distinctive electron populations (parallel and anti-parallel to the magnetic field) can be taken as evidence that the magnetic field lines crossed by MMS are either closed and the electrons are bouncing between the two ionospheres, or that the electron populations were injected onto the field lines as a result of magnetic reconnection in the distant magnetotail and then reflected from the upper ionosphere. In this paper we consider these two possible explanations.
