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C. A. Kletzing
Department of Physics and Astronomy,University of Iowa, Iowa City, IA, USA
F. S. Mozer
Space Science Laboratory, University of California, Berkeley, CA, USA
R. B. Torbert
Department of Physics and Institute for Earth, Oceans, and Space, University of New Hampshire, Durham, NH, USA
Abstract: The background electron temperature and density at
altitudes between 1000 and 8000 km at latitudes greater than 60
invariant latitude have been determined from swept Langmuir probe measurements
from the S3-3 satellite. These plasma parameters are determined by fitting
the measured probe current-voltage relation to the expected theoretical
response. Statistically acceptable fits are found for approximately 20%
of the measurements and do not include measurements within the auroral
density cavity. The derived parameters show a density dependence which
is an inverse a power law with increasing altitude and with a typical density
of 10 cm-3 at 8000 km in altitude. The electron temperature
shows a slight increase with altitude but is less than 5 eV for almost
all measurements. These results suggest that the background plasma outside
of density cavities on high latitude field lines below 8000 km is dominated
by cold plasma of ionospheric origin which is at least an order of magnitude
more dense than hotter magnetospheric components.