Corotating Interaction Regions

Abstract

When spacecraft started to explore the region beyond 1 AU, not surprisingly interesting phenomena were discovered. One of the first new phenomena to be identified was the corotating interaction region (CIR) (Smith and Wolfe 1976), which is the result of the interaction of adjacent fast and slow solar wind streams, as first predicted by Parker (1963). The high speed solar wind streams originate in solar coronal holes, and therefore for CIRs to be seen in the ecliptic plane, there needs to be a low latitude coronal hole at the Sun. This raises the interesting possibility that if we understand the physical processes governing the development and evolution of the CIRs in the heliosphere, then we may be able to make predictions of the charged particle environment based primarily on observations of coronal holes.