Modification of solar wind upstream of the Earth’s foreshock: Multi-instrumental observations

0492208 - ÚFA 2019 DE eng A - Abstrakt
Urbář, Jaroslav - Přech, L. - Němeček, Z. - Šafránková, J.
Modification of solar wind upstream of the Earth’s foreshock: Multi-instrumental observations.
Geophysical Research Abstracts. Vol. 20. Göttingen: European Geosciences Union, 2018. EGU2018-4367-1. E-ISSN 1607-7962.
[EGU General Assembly 2018. 08.04.2018-13.04.2018, Vienna]
Institucionální podpora: RVO:68378289
Klíčová slova: ultra low frequency (ULF) waves * solar wind * plasma * bow shock
Obor OECD: Fluids and plasma physics (including surface physics)
https://meetingorganizer.copernicus.org/EGU2018/EGU2018-13000.pdf

ULF waves that are created due to the interaction of the solar wind plasma with ions reflected at the bow shock
are observed in the ion foreshock region and the interaction of these waves with the solar wind flow leads to its
deceleration. However, according to our study, parameters of the solar wind plasma are modified not only few
Earth radii upstream the bow shock. We observe the solar wind deceleration far upstream the bow shock in regions
not magnetically connected to it. In such clear solar wind, without a presence of fast magnetosonic waves, i.e.
under generally very low magnetic field and plasma fluctuations, the solar wind proton bulk speed deceleration is
not dependent on the level of ULF waves. We found that a ratio of the speeds measured at the L1 point and near
the Earth is a decreasing function of the interplanetary magnetic field cone angle. The effect is not strong—only a
few percent, thus we compare different measurement methods (Faraday cups and electrostatic analyzers) and the
spacecraft in various locations with motivation to rule out the instrumental effects.
Trvalý link: http://hdl.handle.net/11104/0285759