On solar wind - magnetosphere interactions: a statistical survey of lion roars observed at the terrestrial bow shock

0493010 - ÚFA 2019 RU eng A - Abstrakt
Krupař, Vratislav
On solar wind - magnetosphere interactions: a statistical survey of lion roars observed at the terrestrial bow shock.
The 8th biennial VERSIM Workshop: Abstracts. Apatity: Polar Geophysical Institute, 2018.
[VERSIM Workshop /8./. 19.03.2018-23.03.2018, Apatity]
Institucionální podpora: RVO:68378289
Klíčová slova: terrestrial bow shock * whistler-mode emission * solar wind * magnetosphere * Cluster spacecraft
Obor OECD: Fluids and plasma physics (including surface physics)
http://aurora.appl.sci-nnov.ru/pub/VERSIM2018_abstracts.pdf

We investigate the influence of interplanetary (IP) shocks on the intensity of extremely
and very low frequency (ELF/VLF) waves measured by the French DEMETER spacecraft
between 2004 and 2010. DEMETER is particularly useful for this kind of analysis, because
it had a Sun-synchronous orbit (local time 10:30 and 22:30), operated at a low altitude
(700 km) with 14 orbits per day, which allows a fast sampling of a given portion of the
magnetosphere. Altogether, 225 IP shocks were detected in the Wind spacecraft data
(close to L1 point) during the duration of the DEMETER mission (more than 6 years).
Among these, there were 87 fast forward (FF), 31 fast reverse (FR), 59 slow forward (SF),
and 48 slow reverse (SR) shocks. The analysis was performed using one component of
power spectral density of electric field fluctuations measured in the frequency range up
to 20 kHz. The overall geomagnetic activity around the times of the shocks increases after
the time of the shock arrival. However, the variation of the measured wave intensity
(along with the observed time delay) depends on the type of the shock. The most
significant effect was observed for FF shocks. These results were also verified by the
principal component analysis, which allows us to conveniently characterize the measured
wave intensity and its variations.
Trvalý link: http://hdl.handle.net/11104/0286479