EXCITATION OF VLF QUASI-ELECTROSTATIC OSCILLATIONS IN THE IONOSPHERICPLASMA

A numerical solution of the dispersion equation for electromagnetic wa ves in a hot magnetized collisionless plasma has shown that, in a curr ent-free ionospheric plasma, the distortion of the electron distributi on function reproducing the downward flow of a thermal electron compon ent and the compensating upward flow of the suprathermal electrons, wh ich are responsible for the resulting heat flux, can destabilize quasi -electrostatic ion sound waves. The numerical analysis, performed with ion densities and electron temperature taken from the data recorded b y the Inter-kosmos-24 (IK-24, Aktivny) satellite, is compared with a V LF spectrum registered at the same time on board. This spectrum shows a wide frequency band emission below the local ion plasma frequency. T he direction of the electron heat flux inherent to the assumed model o f VLF emission generation is discussed.