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Atmospheric erosion of Venus during stormy space weather

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journal contribution
posted on 24.10.2012, 09:08 by N. J. T. Edberg, H. J. Opgenoorth, H. Nilsson, Y. Futaana, G. Stenberg, S. Barabash, M. Lester, S. W. H. Cowley, J. G. Luhmann, T. R. McEnulty, A. Fedorov, T. L. Zhang
[1] We study atmospheric escape from Venus during solar minimum conditions when 147 corotating interaction regions (CIRs) and interplanetary coronal mass ejections (ICMEs) combined impact on the planet. This is the largest study to date of the effects of stormy space weather on Venus and we show for the first time statistically that the atmosphere of Venus is significantly affected by CIRs and ICMEs. When such events impact on Venus, as observed by the ACE and Venus Express satellites, the escape rate of Venus's ionosphere is measured to increase by a factor of 1.9, on average, compared to quiet solar wind times. However, the increase in escape flux during impacts can occasionally be significantly larger by orders of magnitude. Taking into account the occurrence rate of such events we find that roughly half (51%) of the outflow occurs during stormy space weather. Furthermore, we particularly discuss the importance of the increased solar wind dynamic pressure as well as the polarity change of the interplanetary magnetic field (IMF) in terms of causing the increase escape rate. The IMF polarity change across a CIR/ICME could cause dayside magnetic reconnection processes to occur in the induced magnetosphere of Venus, which would add to the erosion through associated particle acceleration.

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Citation

Journal of Geophysical Research A: SPACE PHYSICS, 2011, 116 (9)

Version

VoR (Version of Record)

Published in

Journal of Geophysical Research A: SPACE PHYSICS

Publisher

American Geophysical Union (AGU); Wiley

issn

0148-0227

Copyright date

2011

Available date

24/10/2012

Publisher version

http://onlinelibrary.wiley.com/doi/10.1029/2011JA016749/abstract

Language

en

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