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The theory of whistler propagation
Author(s) -
Walker A. D. M.
Publication year - 1976
Publication title -
reviews of geophysics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 8.087
H-Index - 156
eISSN - 1944-9208
pISSN - 8755-1209
DOI - 10.1029/rg014i004p00629
Subject(s) - whistler , ionosphere , plasmasphere , ionospheric propagation , duct (anatomy) , physics , magnetosphere , geophysics , very low frequency , computational physics , plasma , astronomy , medicine , pathology , quantum mechanics
Naturally occurring whistlers provide a powerful ground‐based technique for probing the magnetosphere. The major features of the theory of whistler propagation in ducts in the plasmasphere are well understood. The details of how the whistler propagates upward from its source and excites the duct and how it escapes from the duct and reaches the ground are not so clear. Recent direction‐finding experiments are designed to find the point at which the signal emerges from the lower ionosphere; from this the motion in longitude of the duct in which the whistler has propagated is inferred. It is thus important to understand the propagation of the signal between the duct and the lower ionosphere in order to interpret direction‐finding experiments. Another problem of current interest is the amplification of whistlers. In this paper, existing theoretical understanding of the propagation of whistlers is reviewed. The region between the lower ionosphere and the ducts and the mechanisms of excitation of and leakage from the ducts are discussed. An attempt is made to identify those problems which require solution if the whistler technique is to be used to its full effect.