On the alignment of velocity and magnetic fields within magnetosheath jets
File(s)angeo-38-287-2020.pdf (3.17 MB)
Published version
Author(s)
Plaschke, Ferdinand
Jernej, Maria
Hietala, Heli
Vuorinen, Laura
Type
Journal Article
Abstract
Jets in the subsolar magnetosheath are localized enhancements in dynamic pressure that are able to propagate all the way from the bow shock to the magnetopause. Due to their excess velocity with respect to their environment, they push slower ambient plasma out of their way, creating a vortical plasma motion in and around them. Simulations and case study results suggest that jets also modify the magnetic field in the magnetosheath on their passage, aligning it more with their velocity. Based on Magnetospheric Multiscale (MMS) jet observations and corresponding superposed epoch analyses of the angles ϕ between the velocity and magnetic fields, we can confirm that this suggestion is correct. However, while the alignment is more significant for faster than for slower jets, and for jets observed close to the bow shock, the overall effect is small: typically, reductions in ϕ of around 10∘ are observed at jet core regions, where the jets' velocities are largest. Furthermore, time series of ϕ pertaining to individual jets significantly deviate from the superposed epoch analysis results. They usually exhibit large variations over the entire range of ϕ: 0 to 90∘. This variability is commonly somewhat larger within jets than outside them, masking the systematic decrease in ϕ at core regions of individual jets.
Date Issued
2020-03-02
Date Acceptance
2020-01-26
Citation
Annales Geophysicae: atmospheres, hydrospheres and space sciences, 2020, 38 (2), pp.287-296
ISSN
0992-7689
Publisher
Copernicus Publications
Start Page
287
End Page
296
Journal / Book Title
Annales Geophysicae: atmospheres, hydrospheres and space sciences
Volume
38
Issue
2
Copyright Statement
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License (https://creativecommons.org/licenses/by/4.0/).
the Creative Commons Attribution 4.0 License (https://creativecommons.org/licenses/by/4.0/).
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000518780100002&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Physical Sciences
Astronomy & Astrophysics
Geosciences, Multidisciplinary
Meteorology & Atmospheric Sciences
Geology
HIGH-SPEED JETS
SOLAR-WIND
EARTHS MAGNETOSHEATH
BOW SHOCK
MAGNETOPAUSE
PLASMA
Publication Status
Published
Date Publish Online
2020-03-02