Review of pulse impacts on the magnetospheric oscillations

Abstract

Response of magnetospheric oscillatory systems in the ultra-low-frequency (ULF) range on electromagnetic, mechanical, thermal, and chemical impulse action are overviewed and selectively analyzed. Impulses can occur both inside the magnetosphere (e.g. explosion in the geomagnetic tail, impulsive injection of energetic particles) and outside (e.g. solar flare, interplanetary shock wave, thunderstorm discharge, earthquake, volcanic eruption etc.). We suggest systematics of impulses which is based on geophysics and space physics data and is closely related to the theory of ULF oscillations. The systematics is of cognitive and practical importance, and it allows us to interpret a rich variety of responses of the magnetosphere to impulses of the terrestrial and space origins. The classification principle is selected according to which an impulse type is determined from two criteria such as impulse origin location and character of impulse action on one or another oscillatory system of the magnetosphere. The primary conditions for completeness and validity of division are fulfilled because all possible terms of putting impulses to classes, types and forms are specified, and the terms do not overlap. The classification and introduced nomenclature are helpful because they make possible to systematize common properties and specific features of types and forms of impulses. This is especially important with regard to reaction of the Earth’s plasma sheaths to impulses generated during an earthquake preparation as well as under experimental study of dynamic processes in the near-Earth space. The examples of response of ULF oscillations to impulsive actions are shown. The particular focus is given to review of studies which still are not mentioned in reviews and monographies.