Advances in Space Research
Volume 41, Issue 9, 2008, Pages 1347-1352
Distribution and variability of accelerated electrons at Mars
J.S. Halekas, a, , D.A. Braina, R.P. Lina, J.G. Luhmanna and D.L.
Mitchella
aSpace Sciences Laboratory, 7 Gauss Way, University of California,
Berkeley, CA 94720, USA
We investigate accelerated electrons observed by Mars Global Surveyor
(MGS), using data from the Electron Reflectometer (ER) instrument. We
find three different types of accelerated electron events. Current
sheet events occur over regions with weak or no crustal fields, have
the highest electron energy fluxes, and are likely located on draped
magnetotail fields. Extended events occur over regions with moderate
crustal magnetic fields, and are most often observed on closed
magnetic field lines. Localized events have the lowest energy fluxes,
occur in strong magnetic cusp regions, and are the most likely kind of
event to be found on open magnetic field lines. Some localized events
have clear signatures of field-aligned currents; these events have
much higher electron fluxes, and are preferentially observed on
radially oriented open magnetic field lines. Electron acceleration
events, especially localized events, are similar in many ways to
events observed in the terrestrial auroral zone. However, physical
processes related to those found in the terrestrial cusp and/or
plasmasheet could also be responsible for accelerating electrons at
Mars.
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