Parametric instabilities and turbulent heating of a plasma in the field of a fast magneto-acoustic wave

The authors consider the parametric instability of a homogeneous plasma in a magnetic field 0 and in an alternating electric field 0 perpendicular to it. The electric field frequency ω 0 is of the same order as the lower hybrid frequency ω LH , while the amplitude of the relative velocity of the electrons and ions u ∼ cE 0 /B 0 is significantly less than the thermal velocity of the electrons. The authors consider the excitation of longitudinal hydrodynamic oscillations in a cold plasma and of ion sound and electron sound in a strongly non-isothermal plasma. The characteristic values of the maximum growth rate of these oscillations is of the order of ω LH . The results are presented of experiments on turbulent plasma heating by a fast magneto-acoustic wave excited by an alternating radial electric field (f 0 = ω O /2π = 150 MHz, plasma density n 0 = 10 12 − 10 13 cm −3 , B 0 ≤ 5 kG). Under conditions where ω 0 ∼ ω LH there is rapid heating of the electrons and ions to 200 – 400 eV. The observed heating may be attributable to the excitation of a parametric instability.