Global characteristics of the cold plasma in the equatorial plasmapause region as deduced from the geos 1 mutual impedance probe
Thermal plasma parameters derived by the muntal impedance experiment on GEOS are described. The experiment is well suited to the measurement of the electron density and temperature of the outer plasmasphere (when kT/sub e//N/sub e/<1.6 eV/cm/sup 3/). This investigation of the whole set of data supplied by GEOS 1 (4<8, 0000--2400 MLT) covers three main regions: the plasmasphere, an intermediate region of ionospheric refilling, and the plasma trough. In the plasmasphere, we observe profiles with N/sub e/proportionalL/sup -4/, while T/sub e/ stands around 10,000 /sup 0/K or less. The intermediate region, situated next to the plasmasphere and above it, is always present in the day sector, where the ionospheric source plays a leading part. In that zone, the plasma parameters, poorly known up to now, exhibit N/sub e/ values approx.2 to 20 cm/sup -3/, together with T/sub e/ values of 20,000 /sup 0/K on the average, dispersed over a 5,000 to 100,000 /sup 0/K range during disturbances. In the night sector, the intermediate region is seen only during the recovery phase. The region of depleted density is observed at the higher L values in the night and morning MTL sectors. There, plasmas out of Maxwellian equilibrium are seen under disturbed conditions. The dynamic response of the thermal plasma parameters to temporal variations of the a/sub m/ index of magnetic activity follows a known scenario as concerns N/sub e/, making apparent a night-to-day, MTL dependent time delay. As concerns T/sub e/, the dynamical study reveals striking features, such as the persistance of the T/sub e/ modifications into the dusk sector, the interpretation of which remains to be clarified.
- Research Organization:
- Universite d'Orlens et Centre de Recherches en Physique de l'Environment, 45045 Orleans, Cedex, France
- OSTI ID:
- 5496480
- Journal Information:
- J. Geophys. Res.; (United States), Vol. 87:A2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
PLASMAPAUSE
ELECTRON DENSITY
DAILY VARIATIONS
ELECTRON TEMPERATURE
GEOS SATELLITES
IONOSPHERE
PLASMASPHERE
EARTH ATMOSPHERE
MAGNETOSPHERE
PLANETARY IONOSPHERES
SATELLITES
VARIATIONS
640201* - Atmospheric Physics- Auroral
Ionospheric
& Magetospheric Phenomena