Auroral Backscatter Wavelength Dependence Studies.
STANFORD RESEARCH INST MENLO PARK CA
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A description is given of a three-year auroral radar program using six frequencies simultaneously, from 50 MHz to 3000 MHz, at a field site located near Homer, Alaska. Amplitude and Doppler studies of the data were made with the aid of a computer. The frequency dependence of the scattering cross section of the auroral echoes was found to be nearly exponential. The slope of the frequency dependence was found to be time-variant, but averaged 33 dB per 1000 MHz. The aspect sensitivity was found to be nearly independent of frequency, the scattering cross section decreased by about 10 dB per degree of aspect angle. The Doppler shift was found to be proportional to frequency and indicated velocities as high as 1200 meterssec. Comparisons between radar aurora and visual aurora were made that showed moderate correlation suggestions are presented to explain why the correlation was only moderate. Empirical mathematical models were developed and theory is discussed. A new, nonlinear plasma wave concept is introduced. Author
- Atmospheric Physics