Distribution of auroral electrostatic shocks below 8000-km altitude
This paper examines the distributions and characteristics of electrostatic shocks as observed by the S3-3 polar-orbiting satellite. There is auroral oval coverage by the satellite at all magnetic local times and at all altitudes between 240 and 8000 km. Electrostatic shocks are reasonably uniformly distributed in magnetic local time, with a slight increase in the probability of occurrence in the cusp region and a decrease in the post-midnight region (0--6 hours magnetic local time). The occurrence of shocks increases sharply with altitude up to 5000 km, and at a slower rate above 5000-km altitude. Larger shocks tend to occur above 5000-km altitude and between 16 and 22 hours magnetic local time. Electrostatic shocks occur in or near the latitudes of the auroral oval, with few shocks occurring inside the polar cap. Only during periods of high Kp do shocks occur at low latitudes. Shocks occur with greater probability at low altitudes (2000--4000 km) during winter periods than during summer periods. In addition, a comparison of upward flowing ion beams with electrostatic shocks showed that energetic ion beams are associated with shocks but low energy ion beams are not, indicating a possible potential threshold for shocks in ion beams regions. Also, a search for upward flowing ion beams near electrostatic shocks at altitudes below 4000 km showed that upward flowing ion beams occur between 3000--4000 km altitude and between 15--24 hours magnetic local time with at least a 10% probability.
- Research Organization:
- Space Sciences Laboratory, University of California, Berkeley Physics Department, University of California, Berkeley
- OSTI ID:
- 5667957
- Journal Information:
- J. Geophys. Res.; (United States), Vol. 88:A9
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
POLAR-CAP AURORAE
SHOCK WAVES
AURORAL OVAL
DAILY VARIATIONS
ION BEAMS
IONOSPHERE
PLASMA WAVES
POLAR CUSP
SEASONAL VARIATIONS
AURORAE
BEAMS
EARTH ATMOSPHERE
PLANETARY IONOSPHERES
VARIATIONS
640201* - Atmospheric Physics- Auroral
Ionospheric
& Magetospheric Phenomena