The Speed, Density, and Flux Variations in Large-Scale Solar Wind Disturbances

Abstract

The large-scale structure of the solar wind is a topic of considerable interest in the field of solar-terrestrial physics. In fact, the existence of such a structure was inferred from studies of geomagnetic activity long before direct interplanetary observations became possible. Two distinct classes of interplanetary ‘disturbances’ were suggested by these studies — (a) transient, flare-associated shock waves that produced the classical SSC geomagnetic storms, and (b) long-lived, localized plasma streams that produced recurrent geomagnetic activity (see Chapman and Bartels, 1950). The existence of such disturbances has been confirmed by modern in situ observations and the study of the detailed properties of these structures, their solar origins, and their magnetospheric effects has been an important and active area of solar wind research. This paper will concentrate on some recent results in this area that suggest a unified view of large-scale solar wind structures and has some interesting implications regarding the energetics of the related magnetospheric processes.