Modeling corotating interaction regions: From the Sun to 1 AU

Two types of dynamic features dominate the large-scale structure of the solar wind: corotating interaction regions (CIRs) and coronal mass ejections (CMEs). The former result from quasi-stationary conditions at the Sun, whereby solar rotation leads to parcels of plasma with different plasma and magnetic properties becoming radially aligned. This interaction is one of the primary global dynamic processes that shape the structure of the interplanetary medium. In this paper we review the basic processes that lead to the formation and evolution of CIRs between the Sun and 1 AU, describe past and present modeling work aimed at understanding their fundamental features, contrast their properties at solar minimum and maximum, and relate them to potentially geo-effective phenomena. Finally, we describe how improved models and new observations may lead us towards an operational mode of predicting potentially geo-effective phenomena in the future.