Theoretical study of the seasonal and solar cycle variations of stable aurora red arcs
SAR arc statistic provide information on the seasonal and solar cycle variations in the subauroral region electron temperature peak and associated magnetospheric energy source. There are two sources of long-term (solar cycle and seasonal) variability in the magnitude of the subauroral region electron temperature peak and associated SAR are emission intensity: (1) the neutral atmosphere and ionosphere and (2) the magnetospheric energy source. The results of this study indicate that the observed seasonal variation in SAR are intensities can be explained reasonably well by seasonal variations in the neutral atmosphere and ionosphere. True solstice effect are unlikely to result from difference in a near-equatorial magnetospheric heat source since the same heat source supplies both the summer and the winter hemispheres at opposite ends of a common flux tube. Observed solar cycle variations in SAR are intensity for a fixed ring current strength (as represented by the D sub st index) are not consistent with variations predicted solely on the basis of a solar cycle changes in the neutral atmosphere and ionosphere. A reduction of the magnetospheric heat flux by a factor of between 5 and 20 from solar maximum to solar minimum conditions is necessary to bring model electron temperatures and 6300 emission intensity into agreement with observational results for moderately disturbed conditions D sub st approx - 80 gamma. The required reduction in the magnetospheric energy source with decreasing solar cycle is attributed to compositional changes in the magnetospheric plasma.
- Research Organization:
- Air Force Geophysics Lab., Hanscom AFB, MA (USA)
- OSTI ID:
- 5990157
- Report Number(s):
- AD-A-227080/9/XAB; GL-TR-90-0243
- Resource Relation:
- Other Information: Pub. in Jnl. of Geophysical Research, Vol. 95, No. A8, 12219-12234(1 Aug 1990)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
AURORAE
VARIATIONS
EARTH MAGNETOSPHERE
ENERGY SOURCES
IONOSPHERE
ELECTRON TEMPERATURE
EARTH ATMOSPHERE
EMISSION
EQUATOR
HEAT FLUX
MATHEMATICAL MODELS
PLASMA
SEASONAL VARIATIONS
SOLAR CYCLE
STABILITY
THERMOSPHERE
PLANETARY IONOSPHERES
640201* - Atmospheric Physics- Auroral
Ionospheric
& Magetospheric Phenomena