http://worldcat.org/entity/work/id/132250574

HYDROMAGNETIC WAVE PROPAGATION NEAR 1C/S IN THE UPPER ATMOSPHERE AND THE PROPERTIES AND INTERPRETATION OF PC 1 MICROPULSATIONS

PART I: Dispersion and polarization relations are developed from basic considerations for a hydromagnetic wave at about 1 c/s propagating in a cold uniform plasma. The treatment is then extended to include the effects of ion-electron collisions. It is shown that magnetosphere for heights between 10, 000 and 50,000 km (2.6 to 8.8 earth radii). At lower elevations the plasma must be considered as nonuniform. Above 50,000 km the small amplitude assumption is invalid. Finally the theory is extended to include the effects of a multicomponent plasma. PART II: A reasonable hydromagnetic model for the propagation of pc 1 micropulsations is one in which Alfven (left-hand) waves travel along field lines to reach the earth's surface at auroral latitudes and then propagate equatorward is modified Alfven (right-hand) waves just above the ionosphere. The isotropic right-hand wave is constrained to a duct between 400 and 2000 km above the earth by refractive processes. It is shown how many of the observed properties of pc 1's can be related to such a model. Mechanisms for the generation of pc 1's are also discussed and it is concluded that particle instabilities are the most likely source. (Author).

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