Toward a theory of the double plasma resonance in the solar corona

Specific features of the double plasma resonance effect in a magnetized plasma of the solar corona are discussed. The effect consists in enhanced generation of plasma waves in the regions where the upper hybrid frequency coincides with electron gyrofrequency harmonics. It is widely used for interpretation of a fine structure in solar radio emission spectrum in the form of parallel drifting quasi-harmonic stripes of enhanced radiation intensity (zebra pattern). It is shown that the plasma-wave growth rate increases due to both dispersion properties of plasma waves, which are determined by the equilibrium plasma component, and electrons which are non-equilibrium with respect to the velocities transverse to the magnetic field. Special attention is given to an incorrect consideration of the double plasma resonance effect in some papers. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 52, No. 2, pp. 95–108, February 2009.