Особенности генерации квазипериодических ОНЧ-излучений с существенной частотной динамикой внутри плазмосферы

Геомагнетизм и аэрономия. 2025. Т. 65. № 5. С. 620–628.

П.А.Беспалов, О.Н. Савина

Several basic models of frequency dynamics in quasi-periodic VLF emissions with spectral form repetition
periods from 10 to 300 s are considered. In all cases, we are talking about manifestations of cyclotron instability
of electron radiation belts thet are well described within the framework of the plasma magnetospheric maser
theory based an the averaged self-consistent system of quasi-linear equations for waves and particles. Not
too clear spectral elements are characteristic of QP bursts, which are hisses with resonant modulation by
geomagnetic pulsations of the Pc 3-4 range mainly near the upper spectral boundary. Analysis of the equilibrium
in the radiation belts reveals its possible instability caused by the difference in the pitch-angle dependences of
the particle source power and the stationary distribution function. In the nonlinear regime of this instability,
QP 2-radiations are formed, usually with a clear frequency increase in individual spectral fragments. The main
objective of our work is the study of QP 2 emissions with a significant frequency dynamics. This opens up
new possibilities for the diagnostics of space plasma and makes it possible to determine the conditions for
occurrence of the frequently observed quasi-periodic emissions with large and very fast dynamics of the
frequency spectrum, which can be represented as a product of functions dependent on time and frequency.
The study of important details of the excitation of quasi-periodic VLF emissions with significant frequency
dynamics inside the plasmasphere has interesting prospects for further research, and the already achieved level
of understanding of magnetospheric processes has a real diagnostic potential.

Keywords: циклотронная неустойчивость, plasma magnetospheric maser, plasmasphere, плазмосфера, cyclotron instability, quasi-periodic VLF emissions, frequency spectrum dynamics, кваквкквазипериодические ОНЧ-излучения, динамика частотного спектра