Ionospheric Heating Analysis. HF Plasma Line Enhancements at Arecibo
Final technical rept. 1 Oct 1970-1 Dec 1971
RICE UNIV HOUSTON TX
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The non-linear enhancement of the plasma line was observed in January 1971 by Carlson, Gordon and Showen JGR 1972. The enhancement spectrum includes a strong narrow line displaced below the HF 5.62 MHz by the frequency of the ion acoustic waves f sub i in the plasma about 4 kHz a broader line about 30 kc width and other weak lines near the HF a line near f sub i. Enhancements above thermal levels range above a factor of 10,000 and may be taken as verification of the HF excitation of parametric instabilities in the ionosphere. Significant time variations over scales of tens of microseconds through hours were seen. Upshifted and downshifted power dependence, and decay rates of the order of msec. The O-mode but not the X-mode excitation of these enhancements is of significance to heating experiments.
- Atmospheric Physics