The Terrestrial Magnetosphere

Abstract

The magnetosphere is shaped by the interaction between a planetary magnetic field and the solar wind. The magnetopause is a discontinuity separating both fields, forming a cavity in the solar wind. Since the solar wind is a supersonic flow, a standing shock wave, the bow shock, develops in front of the magnetopause. In the anti-sunward direction, the magnetosphere is stretched by the solar wind, forming the magnetotail. Inside the magnetosphere, different plasma regimes exist, dominated by ionospheric plasma in the plasmasphere, a highly variable mixture of ionospheric and heliospheric plasma in the geosphere, and by the solar wind plasma in the outer magnetosphere. These different regimes are coupled by fields and currents. Inside the plasmasphere energetic particles are trapped in the radiation belts.

The poet’s eye, in a fine frenzy rolling, Doth glance from Heaven to Earth, from Earth to Heaven, and, as imagination bodies forth the forms of things unknown, the poet’s pen turns them to shapes, and gives airy nothing a local habitation and a name. Shakespeare, Much Ado About Nothing