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Propagation of Hydromagnetic Waves in Current‐Carrying Regions of the Ionosphere and Magnetosphere (Parallel Propagation)
Author(s) -
Abbas M.,
Poeverlein H.
Publication year - 1968
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/rds19683101010
Subject(s) - physics , dispersion relation , magnetosphere , ionosphere , wave propagation , current density , current (fluid) , computational physics , magnetic field , wave vector , electric field , dispersion (optics) , geophysics , quantum electrodynamics , condensed matter physics , optics , quantum mechanics , thermodynamics
Propagation of hydromagnetic waves in the presence of a constant current density is investigated. The theory is developed from macroscopic equations in which a constant current density is introduced by assuming streaming velocities of the electron and ion fluids. The general dispersion relation is derived, and approximate solutions of the dispersion relation are obtained for special situations. The special cases of this paper refer to a propagation vector in the direction of the magnetic field (“parallel propagation”). In parallel propagation, a transverse current density leaves the propagation vector unaffected, but causes a longitudinal electric field component and a consequent change of the ray direction. With the propagation vector and the current density in the magnetic field direction the effect of currents is significant when J 0 / H 0 is of the order of k ≃ ω/ V a (with H 0 = B 0 / µ 0 and V a as the Alfvém velocity). When the quantity J 0 / H 0 is larger than the wave number k , the current densities lead to a nonconvective instability. A numerical evaluation demonstrates the effect that currents in the ionosphere and magnetosphere may have on the waves.