Mirror mode waves in Venus's magnetosheath: solar minimum vs. solar maximum
The observational rate of mirror mode waves in Venus's magnetosheath for solar maximum conditions is studied and compared with previous results for solar minimum conditions. It is found that the number of mirror mode events is approximately 14 % higher for solar maximum than for solar minim...
Main Authors: | , , , , , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2016-11-01
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Series: | Annales Geophysicae |
Online Access: | https://www.ann-geophys.net/34/1099/2016/angeo-34-1099-2016.pdf |
Summary: | The observational rate of mirror mode waves in Venus's magnetosheath for
solar maximum conditions is studied and compared with previous results for
solar minimum conditions. It is found that the number of mirror mode events
is approximately 14 % higher for solar maximum than for solar
minimum. A possible cause is the increase in solar UV radiation, ionizing
more neutrals from Venus's exosphere and the outward displacement of the bow
shock during solar maximum. Also, the solar wind properties (speed, density)
differ for solar minimum and maximum. The maximum observational rate,
however, over Venus's magnetosheath remains almost the same, with only
differences in the distribution along the flow line. This may be caused by
the interplay of a decreasing solar wind density and a slightly higher solar
wind velocity for this solar maximum. The distribution of strengths of the
mirror mode waves is shown to be exponentially falling off, with (almost) the
same coefficient for solar maximum and minimum. The plasma conditions in
Venus's magnetosheath are different for solar minimum as compared to solar
maximum. For solar minimum, mirror mode waves are created directly behind where the
bow shock will decay, whereas for solar maximum all created mirror modes can
grow. |
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ISSN: | 0992-7689 1432-0576 |