Open Access

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

  • M. Verigin1Email author,
  • G. Kotova1,
  • A. Szabo2,
  • J. Slavin2,
  • T. Gombosi3,
  • K. Kabin4,
  • F. Shugaev5 and
  • A. Kalinchenko5
Earth, Planets and Space201453:BF03351697

DOI: 10.1186/BF03351697

Received: 19 May 2001

Accepted: 13 August 2001

Published: 20 June 2014

Abstract

Between late 1994 and early 2001 the Wind orbiter, generally targeted to stay in the solar wind, passed through the Earth’s magnetosphere 50 times. About 450 distinct bow shock crossings were collected during the inbound and outbound bracketing each Wind perigee. These crossings and corresponding vectorial upstream solar wind measurements by the Wind MFI and SWE 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. The asymmetry of the terrestrial bow shock in the terminator plane is studied as a function of Friedrichs diagram anisotropy. Analysis of the subsolar bow shock position as a function of Alfvenic Mach number M a during intervals of magnetic field aligned solar wind flow shows that the shock tends to approach the Earth when M a is decreasing, while for non field-aligned flows bow shock moves from the planet.