WIND observations of the terrestrial bow shock: 3-D shape and motion

M. Verigin, G. Kotova, J. Slavin, A. Szabo, T. Gombosi, K. Kabin, F. Shugaev, and A. Kalinchenko

Space Research Institute of Russian Academy of Sciences, Profsoyuznaya, 84/32, Moscow, 117810, Russia


Since late 1994 till mid 2000 Wind orbiter, generally targeted to the solar wind monitoring, passed ~50 times through the Earth's magnetosphere. About 400 distinct bow shock crossings were collected in inbound and outbound legs of its trajectory. These crossings and corresponding vectorial upstream solar wind measurements by Wind SWE and MFI instruments are used to study the 3-D shape of the bow shock and its motion. Mapping of bow shock crossings to the Sun-Earth line and to the terminator plane is realized using a recent analytical model of the planetary bow shock. Asymmetry of the terrestrial bow shock in the terminator plane is studied as a function of Friedrichs diagram anisotrophy. Analysis of the subsolar bow shock position as a function of Alfvenic Mach number (Ma) shows that the shock tends to approach the Earth when Ma is decreasing for field-aligned flows of the solar wind, while for non field-aligned flows bow shock moves from the planet.

Earth Planets Space, 53, 1001-1009, 2001