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Group Propagation in the Whistler‐Hydromagnetic Extension of Magnetoionic Theory
Author(s) -
Kantor Gideon,
Pivarunas Frank
Publication year - 1966
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1002/rds1966191093
Subject(s) - whistler , physics , electron , proton , wave propagation , computational physics , refractive index , wave packet , magnetosphere , atomic physics , plasma , optics , quantum mechanics
This paper presents an exact formulation of the propagation of wave packets at whistler and hydromagnetic frequencies m a collisiOn‐free, electrically neutral mixture of electrons and ions of one type. Simple expressions are derived for µ', the group refractive index, and for α, the angle between the direction of propagation of a wave packet and the wave normal; µ' and α are explicit functions of X, Y, θ , the magnetmomc symbols, and R , the electron‐to‐ion mass ratio. Computed valuesof µ' and α for both a wave frequency f slightly above the proton gyrofrequency f M i [ Y = ( f M i / f ) (1/ R )=1500] and somewhat below it (Y=10 4 ) are plotted as a function of X for particular θ values; the µ' and α curves show how magnetoionic theory is modified at low frequencies by including proton motion. Group‐ray refractive index surfaces for the large X values which are applicable to whistler and hydromagnetic wave propagation in the magnetosphere are also presented.