Magnetosheath high speed jets observed with Cluster and MMS with near-Earth upstream solar wind monitors
Abstract
Magnetosheath High Speed Jets (HSJs) are regularly observed downstream of the Earth's bow shock. Determining their origin from spacecraft observations is however a challenge since (1) L1 solar wind monitors are usually used with their inherent inaccuracy when plasma and magnetic data are propagated to the bow shock, (2) the number of measurement points around the bow shock are always limited. Various mechanisms have been proposed to explain HSJs such as bow shock ripples, solar wind discontinuities, foreshock transients, pressure pulses or nano dust clouds and it is difficult to relate these to HSJs with the lack of simultaneous measurements near the bow shock and immediately upstream. We will use a special Cluster campaign, where one spacecraft was lagged 8 hours behind the three other spacecraft, to obtain near-Earth solar wind measurements upstream of the bow shock, together with simultaneous measurements in the magnetosheath. The event of interest is first observed at ACE as a short 10 min. period of IMF-Bx dominant (cone angle around 140 deg.). This IMF-Bx dominant period is also observed, one hour later, by THEMIS B and C (ARTEMIS) and Geotail, which were at 60 and 25 RE from Earth on the dawnside. Cluster 1 just upstream of the bow shock, at 17 RE from Earth, observed also such IMF-Bx dominant period together with energetic ions reflected from the bow shock, variable solar wind beam, foreshock bubbles and hot flow anomalies. Finally, Cluster 3 and 4 and MMS1-4, a few RE from each other downstream of the shock, observed a turbulent magnetosheath with HSJs for 15 minutes. The HSJ characteristics will be investigated with the constellation of 6 spacecraft, as well as their relation with foreshock transients.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMSM038..02E
- Keywords:
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- 2724 Magnetopause and boundary layers;
- MAGNETOSPHERIC PHYSICS;
- 2740 Magnetospheric configuration and dynamics;
- MAGNETOSPHERIC PHYSICS;
- 2756 Planetary magnetospheres;
- MAGNETOSPHERIC PHYSICS;
- 2784 Solar wind/magnetosphere interactions;
- MAGNETOSPHERIC PHYSICS