Relationship between energy flux Q and mean energy of auroral electron spectra based on radar data from the 1987 CEDAR Campaign at Sondre Stromfjord, Greenland
- Computational Physics Inc., Fairfax, VA (United States)
- Aerospace Corp., Los Angeles, CA (United States)
- SRI International, Menlo Park, CA (United States)
The incoherent scatter radar at Sondre Stromfjord, Greenland, measured electron density profiles from 90 to 500 km during four auroral events over a 3-hour period on February 28, 1987. The profiles were obtained with the radar pointed along the magnetic field near zenith at 15-s intervals. Under the assumption that proton/H atom precipitation was unimportant during these events a representation of the incident electron flux was obtained by fitting calculated profiles with measured profiles in the vicinity of their peaks (lower E region). Maxwellian and Gaussian electron distributions with high- and low-energy tails were used to generate the calculated profiles. The distributions were specified in terms of average energy and energy flux Q. The authors find that they can clearly distinguish between profiles that result from a Maxwellian incident electron spectrum and those that result from a Gaussian spectrum. Interpreting Gaussian and Maxwellian spectra as representative of discrete and diffuse aurora, respectively, the measurements indicated good correlation between and Q for discrete aurora, while essentially no correlation was observed for diffuse aurora. This is consistent with current understanding that discrete auroras are produced by electrons accelerated by magnetic field-aligned potential drops whereas diffuse auroras are produced by pitch angle diffusion of plasma sheet electrons into the loss cone. 27 refs., 8 figs., 2 tabs.
- OSTI ID:
- 50533
- Journal Information:
- Journal of Geophysical Research, Vol. 99, Issue A10; Other Information: PBD: 1 Oct 1994
- Country of Publication:
- United States
- Language:
- English
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