Ip: Global Solar Wind Interaction and Ionospheric Dynamics 605 605 Global Solar Wind Interaction and Ionospheric Dynamics

The spacecraft missions to Comets 21P/Giacobini-Zinner and 1P/Halley in the mid-1980s revolutionized our knowledge of comets and their interaction with the solar wind. Besides the large-scale plasma structures, the spacecraft in situ measurements produced many exciting and surprising results about the ion distribution and magnetic field configuration in the inner regions of cometary comae. These earlier scientific explorations laid the foundation for the Deep Space 1 mission to Comet 19P/Borrelly and groundbased observations of recent bright comets such as Comets 1996 B2 (Hyakutake) and 1995 O1 (Hale-Bopp). In this chapter, we review the mor-phological structures of cometary ion tails, analytical and numerical simulations of comet-solar wind interactions, plasma boundaries and the ionospheric contact surface identified by spacecraft measurements, and plasma instabilities and waves. 1