Abstract
JOURNAL OF GEOPHYSICAL RESEARCH,
VOL. 112,
E04S10,
13 PP., 2007
doi:10.1029/2006JE002820
Space weather at Venus and its potential consequences for atmosphere evolution
Space Sciences Laboratory, University of California, Berkeley, Berkeley, California, USA
NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
Institute of Geophysics and Planetary Physics, University of California Los Angeles, Los Angeles, California, USA
Space weather storms at the Earth are dominated by the magnetosphere's response to coronal mass ejections, or CMEs, whose disturbances propagate through the solar wind to 1 AU, and to a lesser extent by the pressure ridges associated with the interactions of solar wind streams with different properties. The interplanetary signatures of these events include high solar wind dynamic pressures and high interplanetary magnetic fields, the same parameters that cause compression and/or magnetization of the ionosphere at weakly magnetized Venus. The nature of Venus' response to these events is also expected to include increased atmosphere erosion by the solar wind interaction, a matter of potential interest for historical extrapolations of atmosphere escape. We consider the possible evidence for enhanced escape during these disturbances in the data from the Pioneer Venus Orbiter (PVO). Available magnetometer and plasma analyzer results are used to identify periods of interest and the interplanetary characteristics of the disturbed periods. It is found that the suprathermal (>36 eV) ion measurements from the Pioneer Venus neutral mass spectrometer (ONMS) provide convincing evidence of the related enhanced escape of mostly O+ suprathermal ions. The results provide the first direct demonstration that space weather has played an important role in Venus (and other weakly magnetized planet) atmosphere loss through time. It is important to pursue study of these effects with the new measurements from Venus Express and, in light of the approaching solar activity cycle rising phase, extremely timely.
Received 28 August 2006; accepted 30 January 2007; published 21 April 2007.
Citation: (2007), Space weather at Venus and its potential consequences for atmosphere evolution, J. Geophys. Res., 112, E04S10, doi:10.1029/2006JE002820.
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