The Response of a Plasma Magnetospheric Maser to Atmospheric Perturbations

Abstract

The effect of weak external influences associated with infrasonic waves in the ionosphere on the operation of a plasma magnetospheric maser (PMM) is considered. It is shown that if the frequency of infrasonic waves is close to the eigen frequency oscillations of the PMM, then quasi-periodic (QP) electromagnetic VLF emissions with repetition periods of spectral forms of 10–300 s can be excited in radiation belts. It has been found that one of the possible reasons for this phenomenon may be the Q-switching of the magnetospheric resonator due to a change in the coefficient of reflection of whistler waves from the ionosphere from above by atmospheric infrasonic waves. For natural atmospheric sources of infrasonic disturbances with horizontal scales of approximately 100 km, model calculations of the depth of modulation of the energy density of electromagnetic waves in a magnetic field tube were carried out. It has been found that in the morning and daytime subauroral magnetosphere, even weak external influences lead to the appearance of signals with a sufficiently large modulation depth (tens of percent).