ELF and VLF radio waves

This review covers developments in ELF and VLF radio-wave propagation resea rch over the last 50 years of the Journal of Atmospheric and Solar-Terrestr ial Physics. A review of such a large field, over such a long period, canno t be fully comprehensive and the authors have therefore covered important a reas which have they themselves have found interesting. The survey begins w ith a review of work on natural and man made sources of ELF and VLF radiati on. This is followed by sections on experimental and theoretical studies of unperturbed (ambient) ELF and VLF radio propagation. Schumann resonance re search, which is currently undergoing a renaissance, is then reviewed. A re view of research into transient perturbations of ELF and VLF propagation fo llows, extending from the early work on nuclear explosions up to the curren t work on sprites. The review concludes with a brief summary of the VLF nav igation systems of the USSR and USA, (Alpha and Omega) whose development an d life-span covered most of the last 50 years. (C) 2000 Elsevier Science Lt d. All rights reserved.