ABSTRACT
This chapter elaborates about the coupling of the solar wind to the Earth’s magnetosphere and discusses the multifaceted reaction of the magnetosphere–ionosphere system to that coupling. The magnetosphere’s interaction with the solar winds largely controls its morphology and the locations of its plasmas. The Earth’s magnetosphere–ionosphere system responds to time variations in the properties of the solar wind hitting the Earth. The chapter overviews different types of solar wind coming from the Sun, discusses the nature of the 11-year solar cycle, and examines the properties of the solar wind throughout the heliosphere and at the orbit of Earth. It discusses the interplanetary magnetic field clock angle and the Russell–McPherron effect to discuss what geomagnetic indices are. When the coupling of the solar wind to the Earth’s magnetosphere becomes strong, the magnetosphere–ionosphere system reacts in a number of ways. Proton aurora, which can occur equatorward of the electron aurora, are magnetically connected to the ion plasma sheet in the magnetosphere.
