The Solar Wind and Its Interaction with the Interstellar Medium

The solar wind is a magnetized plasma of ions and electrons which flows outward from the Sun. This chapter begins with a brief history of the discovery of the solar wind. Solar wind properties at 1 AU are discussed as well as how these properties change over a solar cycle. The solar wind evolves as it moves outward through the solar system and interacts with the interstellar neutrals which slow and heat the wind. The solar wind runs into a variety of obstacles as it moves outward, the non-conducting Moon and asteroids, comets and unmagnetized planets where the atmosphere forms a conducting barrier, and magnetized planets with large magnetospheres. Finally the solar wind reaches the interstellar medium, going through the termination shock and then diverting down the tail of the heliosphere.