Atmospheric sciences: Active very low frequency experiments on the magnetosphere from Siple Station, Antarctica

Abstract

V.l.f. coherent waves transmitted from Siple Station, Antarctica, provide a novel means for the study and control of the magnetosphere and ionosphere. Through cyclotron resonance the waves exchange energy with radiation belt electrons, causing wave growth ( ca. 10 3 in power), wave-wave interaction and modification of the distribution of electrons. The measured growth rates give information on the flux of energetic electrons along the path of propagation. Precipitation induced by v.l.f. waves from lightning, ground transmitters and power grids, alters the ionosphere, affecting propagation (e.l.f., v.l.f., l.f., h.f.) and providing a controlled forcing function for the study of ionospheric processes. The active experiments are supported by the L =4 network of whistler stations in the Antarctic; they provide data on the distribution and movement of the magnetospheric plasma. Both the active and the passive v.l.f. experiments will contribute important data to the I.M.S. (International Magnetospheric Survey) and to the associated space experiments of the I.S.E.E. (International Sun-Earth Explorers) and E.E. (Electrodynamic Explorer) programmes.