Space Weather

Michael Gedalin

The Sun governs the life of the Earth. Solar-terrestrial relations occur not only via radiation coming to the Earth but also via time-varying plasma flow (Fig. 1). This solar wind is decelerated and diverted by the bow shock forming at the distance of about 10 Earth radii toward the Sun. The diverted plasma flows around the Earth, shaping a magnetosphere (Fig.2) with a long tail and a current sheet where the so called "magnetic reconnection" (Mov. 1) occurs, causing magnetic substorms (Mov. 2). We study the basic processes in this interaction: mirror waves generated behind the shock because ions are heated more in a direction perpendicular to the magnetic field (1, 2), nonlinear waves propagate in plasma and steepen similar to "shallow water waves" (3), bow shocks are formed around the planets with or without global magnetic field and energize ions and electrons (4, 5, 6), magnetic field lines locally reconnect in the current sheet in an avalanching way (7, 8).
 

Figure 1: The Solar Wind	Figure 2: The Magnetosphere

Movie 1: Magnetic Reconnection (mov, avi)

Movie 2: Magnetic Substorms (mov, avi)