Sun-Earth electrodynamics: The solar wind connection

R. P. Lepping, D. B. Berdichevsky, and C.-C. Wu

Laboratory for Extraterrestrial Physics, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771

Abstract:

The solar wind's role in Space Weather, from solar processes that are responsible for the wind to the solar wind-magnetosphere interaction, is reviewed. We stress the importance of large transient structures in the solar wind in that role, but discuss quasi-periodic structures as well. The primary parameters controlling the main coupling of the solar wind with the Earth's magnetosphere are presented. They are the strength and direction of the interplanetary magnetic field (IMF), the solar wind's speed and density, their interplay, and the intensity of solar energetic particles. Discussed are the dramatic disturbances to the geomagnetic environment during times when the Earth's magnetosphere is "open," i.e., when its boundary has a significant normal magnetic field over a large enough area to allow significant particle entry. It is argued that interplanetary magnetic clouds, for various reasons, especially due to their strong and smoothly varying magnetic fields, play an important part in solar wind-magnetosphere coupling, and hence, they receive special attention. Some common "threads" connecting these separate regions are described, as well as the properties and importance of interplanetary shock waves.

Research Signpost, Res. Devel. in Astrophys., 1, 139-171, ISBN: 81-271-0004-8, 2003