Journal article
Micro‐Scale Plasma Instabilities in the Interaction Region of the Solar Wind and the Martian Upper Atmosphere
Journal of geophysical research. Space physics, Vol.127(5), e2022JA030591
05/2022
DOI: 10.1029/2022JA030591
Abstract
We present results, obtained by several instruments onboard NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft, that show that the interaction region of the solar wind and the Martian upper atmosphere coincides with intense plasma wave activity. The turbulence region features nonlinear structures, identified as ion phase‐space holes and double layers, that emerge in the saturation phase of instabilities in the ion‐acoustic frequency range. One‐dimensional particle‐in‐cell simulations suggest that the waves and the nonlinear structures are very effective in coupling the flowing solar wind and the Martian plasma. Specifically, the simulations show that the magnetic field‐aligned component of the solar wind protons decelerates by about 20% in temporal and spatial scales of the orders of ∼100 ms and several kilometers, respectively. The results thus suggest that the waves may play an important role in the interaction region.
Plain Language Summary
Unlike Earth, Mars does not have a global dipole magnetic field to protect its upper atmosphere against the solar wind. In the absence of this magnetic shield, charged particles originating from the Sun stream through the Martian upper atmosphere and strip away a small fraction of ions from its ionosphere. The relative importance of various mechanisms that lead to the transfer of energy and momentum from the flowing solar wind to the Martian ions is not fully understood. Here, we present data obtained by NASA’s MAVEN spacecraft that shows that the interaction region of the solar wind and the Martian plasma environment features intense plasma waves. Simulations suggest that the electric fields of these waves can efficiently couple the charged particles from the solar wind with those from the Martian ionosphere and facilitate the exchange of energy and momentum.
Key Points
Plasma waves in the frequency range of ion acoustic and lower‐hybrid frequencies are often observed along with accelerated planetary ions
The turbulence region features ion phase‐space holes and double layers that likely evolve from waves in the ion acoustic frequency range
Wave structures are very effective in coupling the flowing solar wind and the Martian plasma
Details
- Title: Subtitle
- Micro‐Scale Plasma Instabilities in the Interaction Region of the Solar Wind and the Martian Upper Atmosphere
- Creators
- Hassanali Akbari - Goddard Space Flight CenterDavid Newman - University of Colorado BoulderChristopher Fowler - West Virginia UniversityRobert Pfaff - Goddard Space Flight CenterLaila Andersson - Laboratory for Atmospheric and Space PhysicsDavid Malaspina - Laboratory for Atmospheric and Space PhysicsSteven Schwartz - Laboratory for Atmospheric and Space PhysicsRobert Ergun - Laboratory for Atmospheric and Space PhysicsJames McFadden - University of California, BerkeleyDavid Mitchell - University of California at BerkeleyJasper Halekas - University of IowaDouglas Rowland - Goddard Space Flight Center
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.127(5), e2022JA030591
- DOI
- 10.1029/2022JA030591
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Number of pages
- 9
- Grant note
- Villum Fonden (Villum Foundation)
- Language
- English
- Date published
- 05/2022
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984428801002771
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