Seasonal variations in the subauroral electron temperature enhancement

Journal Article · Sat Jun 01 00:00:00 EDT 1991 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/91JA00791· OSTI ID:5181611

Fok, M C; Kozyra, J U; Warren, M F ^[1]; Brace, L H ^[2]

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1. Univ. of Michigan, Ann Arbor (USA)
2. NASA Goddard Space Flight Center, Greenbelt, MD (USA)

The subauroral nightside electron temperature peak is one of the phenomena showing the response of the subauroral ionosphere to the influx of magnetic storm energy in the vicinity of the plasmapause. A statistical study of the seasonal variations of the subauroral electron temperature enhancement was undertaken using data from the Langmuir probe experiment on the DE 2 satellite throughout most of the mission (1981-1982). In the winter hemisphere the nighttime background electron temperature is the highest and the magnitude of the peak T{sub e} responds most weakly to the geomagnetic activity. This behavior can be explained by seasonal trends in the nighttime downward heat flux due to conjugate photoelectrons. Moreover, model results indicate that a factor of {approximately}3 increase in heat inflow during equinox relative to solstice is required to raise the electron temperature to a given level. This is a consequence of the higher electron densities at the T{sub e} peak near equinox. The T{sub e} peak occurs on field lines which thread the outer plasmasphere in the vicinity of the plasmapause and thus can be used as a tracer of the plasmapause position. Correlating the position of the T{sub e} peak with K{sub p} (the highest value of 3-hour K{sub p} in the preceding 12 hours) indicates a trend toward a more expanded quiet time plasmasphere and one which is more easily compressed by magnetic storms at equinox than during the solstice period.

• OSTI ID: 5181611
• Journal Information: Journal of Geophysical Research; (United States), Vol. 96:A6; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
IONOSPHERE
ELECTRON TEMPERATURE
MAGNETIC STORMS
IONOSPHERIC EFFECTS
CORRELATIONS
HEAT FLUX
LANGMUIR PROBE
MATHEMATICAL MODELS
PLASMAPAUSE
PLASMASPHERE
SATELLITES
SEASONAL VARIATIONS
STATISTICS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTRIC PROBES
MATHEMATICS
PLANETARY IONOSPHERES
PROBES
VARIATIONS
640201* - Atmospheric Physics- Auroral
Ionospheric
& Magetospheric Phenomena