Sov. J. Plasma Phys. (Engl. Transl.); (United States) · 1978 · 23 citations · 0 references
Natural SciencesEarth SciencesPhysicsAtmospheric SciencePlasma PhysicsSpectroscopyAtomic Emission SpectroscopyElectromagnetic WavesIonospheric ElectrodynamicsOxygen EffectPlasma WavesBroadband AbsorptionEmission Line SpectroscopyEmission Line StudiesIonospheric AbsorptionIonospheric CurrentsIonospheric DisturbancesParametric Subharmonic InstabilityRadio Emission Mechanisms
Intense rf pulses at a frequency ..omega../sub 1/ near the electron gyrofrequency ..omega../sub H/ cause an intensification of the red emission line of atomic oxygen at the wavelength lambda=6300 A in the F layer of the ionosphere at an altitude zapprox.200 km. The experiments also reveal an anomalous broadband absorption of radio waves when the ionosphere is perturbed at a frequency ..omega../sub 1/approx. =..omega../sub H/. This effect is shown to be in accordance with the theory of resonant absorption. The accelerated electrons are apparently due to the excitation of a parametric instability.