Spectral features of stimulated electromagnetic emission, measured in the 4.3–9.5 MHz pump wave frequency range

Steady state spectral features of stimulated electromagnetic emissions (SEEs) for their major emission components (DM, NC, BC, BUM, and BUS) are studied in a wide pump wave frequency range, from 4.3 to 9.5 MHz, i.e., from slightly above the 3rd to slightly above the 7th gyroharmonic frequency. Based on these systematic experimental data, new peculiarities in the behaviour of the SEE intensity and of the spectral properties, in relation to the gyroharmonic mode number, have been found. The experimental results, discussed in the paper, were collected during the years 1996–2000 at the Sura heating facility in Russia by modification of the ionospheric F region, using ordinary mode HF pump waves.