Remote Sensing the Inner Magnetosphere

Frederick Menk (School of Mathematical and Physical Sciences and Cooperative
Research Centre for Satellite Systems, Callaghan, NSW, 2308), Mark Clilverd, 
Bill Sandel, Jerry Goldstein 
 

By using arrays of closely-spaced ground magnetometers it is possible to
determine the resonant frequency of ULF waves in the inner magnetosphere. The
resonances occur during the local daytime and can often be observed for several
hours. This provides information on the plasma mass density near the field line
apex in the dayside magnetosphere with a time resolution of about 40 min.
Furthermore, motion of plasmaspheric field aligned ducts can be observed by
analysing the Doppler shift of ducted man-made whistler-mode signals. These
provide information on electron density near the field line apex. When combined
with the ULF technique, it is possible to estimate the mass loading. We examine
data from an experiment operated in Antarctica using magnetometers and a VLF
receiver to monitor the same L=2.5 flux tube, and compare these results with
in-situ measurements and plasmaspheric imaging using the IMAGE RPI and EUV
experiments. We investigate quiet and moderately disturbed days, including cases
when density structures are present, and compare these observations with
mathematical modelling of the constituent densities and temperatures for this
flux tube. These measurements provide the first intercalibration of different
ground-based and in situ techniques and lend new insight on plasma dynamics
within the plasmasphere.

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Presented at the August 2003 AGU Chapman Conference, Helsinki, Finland