ISAS-NASA geotail satellite (1992) #18

Abstract

GEOTAIL spacecraft launched on 24 July 1992 has explored the Earth’s magnetotail across the range of 10-210 REfrom the Earth. GEOTAIL not only clarified the basic structure of the magnetotail both in quiet and active times, but it also revealed the kinetics of the plasma that underlies macroscopic dynamics. In the magnetotail magnetic reconnection is the key process which governs energy dissipation and acceleration of ions and electrons. GEOTAIL has addressed the relation between the reconnection and auroral phenomena and clarified the kinetics of the energy conversion process in the reconnection region that operates on the scale of the ion inertia length. Understandings have also been advanced on the entry of the solar wind plasma into the magnetotail due to turbulence generated on the magnetopause and the excitation of plasma waves on account of prevalent nonequilibrium velocity distributions of plasma particles. The processes addressed by in-situ observations by GEOTAIL in space should be common to collisionless plasmas that prevail in astrophysical objects.