INTERACTION OF THE LONG-PERIOD ULF WAVES AND CHARGED PARTICLE IN THE MAGNETOSPHERE: THEORY AND OBSERVATIONS (OVERVIEW)

The paper reviews the current state of the problem of interaction between long-period ultra-low-frequency (ULF) waves and high-energy particles. We consider elements of the theory of energy exchange between waves and particles, particle transport across magnetic shells under the influence of the electromagnetic field of a wave, the acceleration of radiation belt particles by both resonant and non-resonant mechanisms We examine the mechanisms of generation of azimuthally-small-scale ULF waves due to instabilities arising from the wave-particle resonance. The cases of Alfven, drift-compressional, and drift-mirror waves are analyzed. It is noted that due to the lack of a detailed theory of drift-mirror modes, the possibility of their existence in the magnetosphere cannot be taken as a proven fact. We summarize experimental data on the poloidal and compression ULF waves generated by unstable populations of high-energy particles. We investigate the mechanisms of modulation of energetic particle fluxes by ULF waves and possible observational manifestations of such modulation. Methods of studying the structure of waves across magnetic shells by recording fluxes of resonant particles with a finite Larmor radius are discussed.