A Discussion on the early days of ionospheric research and the theory of electric and magnetic waves in the ionosphere and magnetosphere - Coherent v.l.f. waves in the magnetosphere

Abstract

V.l.f. whistler-mode waves in the magnetosphere may be generated by natural lightning and v.l.f. transmitters, or through resonant interactions with radiation belt electrons. Such v.l.f. waves provide information on the hot and cold components of the magnetospheric plasma. Energetic electrons precipitated by whistler-mode waves may generate Bremsstrahlung X-rays and enhance the electron density of the ionosphere. Coherent signals transmitted from the ground can be amplified up to 30 dB in the magnetosphere; the amplified signal may trigger discrete v.l.f. emissions of both rising and falling frequency. V.l.f. line radiation from the magnetosphere is observed, apparently controlled by power line harmonic radiation from the ground. Triggered emission can be explained by using a new principle in which waves and cyclotron-resonant electrons interchange energy through a feedback process. Applications of controlled wave injection include: (1) diagnostic study of the magnetosphere; (2) plasma physics experiments; (3) controlled precipitation; and (4) v.l.f. communications.