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Venus bow shocks at unusually large distances from the planet
Author(s) -
Steinolfson R. S.,
Cable S.
Publication year - 1993
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/93gl00839
Subject(s) - bow shock (aerodynamics) , venus , physics , solar wind , planet , bow wave , mach number , magnetopause , shock (circulatory) , orbiter , geophysics , shock wave , astrophysics , astronomy , mechanics , plasma , astrobiology , quantum mechanics , medicine
Recent analysis of data from the Pioneer Venus Orbiter (PVO) has shown that the bow shock often travels to unusually large distances from the planet when the solar wind magnetosonic Mach number is near unity. We suggest that distant bow shocks can be explained as an integral part of the response of the global solar wind/Venus interaction to the anomalous local solar wind conditions that existed during the time of these observations. The lower than normal plasma beta and magnetosonic Mach number are in a parameter regime for which the usual fast‐mode bow shock close to the planet may not provide the necessary compression and deflection of the solar wind. Using MHD simulations we show that, for these conditions, the usual fast shock is replaced by a bow shock consisting of an intermediate shock near the Sun‐Venus line and a fast shock at large distances from the Sun‐Venus line. This composite bow shock propagates upstream away from the planet at a low speed and appears to be approaching a new equilibrium stand‐off location at a large distance from the planet.