Solar wind control of the magnetopause location: New insight

0474174 - ÚFA 2018 DE eng A - Abstract
Němeček, Z. - Šimůnek, Jiří - Šafránková, J. - Shue, J.-H. - Samsonov, A. A.
Solar wind control of the magnetopause location: New insight.
Geophysical Research Abstracts. Göttingen: European Geosciences Union, 2017. EGU2017-3722. ISSN 1607-7962.
[EGU General Assembly 2017. 23.04.2017-28.04.2017, Vienna]
Institutional support: RVO:68378289
Keywords : solar wind * magnetopause * interplanetary magnetic field
Subject RIV: BL - Plasma and Gas Discharge Physics
http://meetingorganizer.copernicus.org/EGU2017/EGU2017-3722.pdf

The solar wind dynamic pressure is believed to be the principal factor controlling the magnetopause location. Their
mutual relation is usually considered in a power-law form and suggested indices vary from −1/4.8 to −1/6.6 in
present magnetopause models. In the paper, we analyze THEMIS dayside magnetopause crossings observed in
a broad range of upstream pressures (0.2–20 nPa) and discuss the relationship between the dynamic pressure and
the magnetopause stand-off distance and flaring angle. We found that although the power-law form provides the
best description of variations of the stand-off distance with upstream pressures for a full set of crossings as well
as for subsets constrained by a sign of the interplanetary magnetic field (IMF) vertical component, IMF cone
angle, and solar wind speed, the most appropriate value of the power index resulting from the present study is
−1/3.83 if only a dependence on the upstream solar wind pressure is considered. We discuss power index variation
dependences on the IMF direction and solar wind speed and influence of the orbital-spacecraft limitations.
Permanent Link: http://hdl.handle.net/11104/0271283