Plasmaspheric mass and electron densities during a prolonged disturbed interval

Menk, F.W., Grew, R.S., Clilverd, M.A., Sandel, B R.


The inner magnetosphere plasma environment can be rather disturbed during and
after magnetic storms. Recent discoveries include plasma structures described as
plumes, channels, notches, and shoulders. Observational data usually come from
spacecraft and ground-based VLF whistler techniques. However, VLF receivers can
also be used to monitor artificially produced whistler-mode waves that propagate
in field-aligned ducts and that provide information on the electron density near
the equatorial plane. Furthermore, ground magnetometers can be used to detect
ULF field line resonances whose frequency relates to the plasma mass density
near the equatorial plane. We describe experiments using magnetometer arrays and
VLF receivers to measure mass and electron density in the inner magnetosphere
during an extended disturbed interval in October 2002. Comparison with IMAGE EUV
images allows intercalibration of the experiments. We thus compare VLF-derived
electron densities and ULF mass densities with EUV images to obtain estimates of
the temporal variation in the He+ and O+ concentrations under disturbed
conditions.

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Fall Meeting, American Geophysical Union, San Francisco, U.S.A., 
5-9 December 2005