[P-EM17] 宇宙プラズマ科学

[PEM17-03] Insights into the Structure of Quasiparallel Shocks from VEX Data.

*Michael A Balikhin¹、Michael Gedalin²、Simon N. Walker¹ (1.University of Sheffield、2.Ben Gurion University)

キーワード：Collisionless Shock, Venus

Venus does not possess an intrinsic magnetic field. The Venusian ionosphere forms the obstacle within the solar wind flow, resulting in the formation of the Venusian bow shock. The subsolar standoff distance of the Venusian bow shock is much smaller in comparison with the terrestrial bow shock, that results from the interaction between the solar wind and the intrinsic magnetic field of the Earth. This translates into much smaller spatial size of Venusian shock and foreshock. This limits the time for wave growth in the unstable foreshock region. Therefore the Venusian environment is more favourable for observations of the quasiparallel shock front structure that are not masked by high amplitude waves and nonlinear structures such as SLAMS. Here, observations of quasiparallel shock crossings by Venus Express are presented and compared with a two-fluid analytic model of the shock front.