The relation of sub-auroral electron and proton precipitation to
plasmaspheric and magnetospheric conditions.

T. J. Immel, S. B. Mende, H. U. Frey
  Space Sciences Laboratory, UCB

G. Lu
  High Altitude Observatory, NCAR

B. R. Sandel, T. Forrester
  Lunar and Planetary Laboratory, U Arizona

A. J. Ridley
  Space Physics Research Laboratory, U of M

  In the first two years of the NASA IMAGE mission, global-scale images of
auroral precipitation have revealed electron and proton precipitation away
from the main auroral oval. The most common manifestations include detached
proton arcs in the dusk sector, and impulsive precipitation of electrons and
protons on the dayside. A third type of auroral form was observed during the
recovery phase of the July 15-17, 2000, magnetic storm, where continuous
precipitation of low energy electrons and protons is observed in a dayside
detached arc extending over several hours of local time.

  In this investigation, the relation of each of these events to
magnetospheric conditions, particularly convection electric fields and
field-aligned currents, is examined using the AMIE electric field model.
Additionally, the IMAGE satellite regularly observes the extent and
morphology of the plasmasphere. The role of the interaction of cold and
energetic plasmas can therefore also be studied. In-situ satellite data aid
the study by providing precipitating particle and electric field information
with each pass.

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Fall 2002 Meeting of the American Geophysical Union
San Francisco, CA, USA, 6-10 December 2002