Energy addition in the solar wind

Abstract

A general study of energy addition, energy loss, and energy redistribution in the solar wind, for both spherically symmetric and rapidly diverging flow geometries, is presented. It is found that energy addition in the region of subsonic flow increases the solar wind mass flux but either has little effect on (for heat addition) or significantly reduces (for momentum addition) the solar wind flow speed at 1 AU. In contrast, energy addition in the region of supersonic flow has no effect on the solar wind mass flux but significantly increases the flow speed at 1 AU. It is also found that both momentum loss in the subsonic region and energy exchange (involving loss in the subsonic region and gain in the supersonic region) can lead to an increase in the asymptotic flow speed. This general study thus places certain constraints on viable mechanisms for driving high‐speed solar wind streams and points to a number of specific, self‐consistent studies of such mechanisms that need to be carried out in the future.