Journal article
Observation of Electric Field Enhancement at Ion Composition Boundary at Mars and Its Relation to Oxygen Acceleration
Geophysical research letters, Vol.52(4), e2024GL113584
02/28/2025
DOI: 10.1029/2024GL113584
Abstract
Direct electric field measurements during certain ionosphere‐magnetosheath transitions on the dayside of Mars reveal a presence of localized (20 km thickness along vertical direction) strong (40 mV/m) electric field located at the solar wind stagnation point. This electric field is nearly collocated with the ion composition boundary where ionospheric oxygen ions are observed to be accelerated up to 1 keV, forming a layer of higher temperature plasma around the stagnation point. Simulations demonstrate that the observed localized electric field enhancement can create this hotter plasma layer population on either side of the boundary. This plasma layer can have an impact on the solar wind coupling with the planet and forms a reservoir for heavy ion escape.
Solar wind, being heated and decelerated at the bow shock of Mars, begins to flow around the planet, and its ions generally reach altitudes as low as 500–700 km on the dayside of the planet. Below this altitude, in the ionosphere, the plasma environment is dominated by heavier ions of planetary origin, and the region in between, where number densities of both population are equal, is often referred to as the ion composition boundary (ICB). Observations show that sometimes particles of the upper part of the ionosphere are accelerated to energies as high as 1 keV and are diverted back to the planet or leak to the shocked solar wind region located above. Interestingly, these instances coincide with the presence of a localized large amplitude electric field enhancement at the ICB. Current study employs particle tracing simulations to determine if the observed feature in the electric field may be responsible for backward acceleration of ionospheric ions and their upstream leakage. The results provide an insight on a new feature of solar wind interaction with planetary plasma envelope which helps to better understand the processes of ion energization and escape on Mars.
A localized electric field enhancement is observed at the solar wind stagnation point Observations of the electric field enhancement coincide with accelerated ionospheric oxygen ions up to 1 keV Simulation suggests that the observed ion acceleration can be explained by the measured electric field enhancement
Details
- Title: Subtitle
- Observation of Electric Field Enhancement at Ion Composition Boundary at Mars and Its Relation to Oxygen Acceleration
- Creators
- Sergey D. Shuvalov - University of Colorado BoulderLaila Andersson - University of Colorado BoulderKathleen Gwen Hanley - University of California, BerkeleyJasper S. Halekas - University of IowaDavid L. Mitchell - University of California, BerkeleyJared R. Espley - Goddard Space Flight Center
- Resource Type
- Journal article
- Publication Details
- Geophysical research letters, Vol.52(4), e2024GL113584
- Publisher
- AMER GEOPHYSICAL UNION
- DOI
- 10.1029/2024GL113584
- ISSN
- 0094-8276
- eISSN
- 1944-8007
- Grant note
- NASA: NNH10CC04C NASA funding for the MAVEN project through the Mars Exploration Program
This work was supported by NASA funding for the MAVEN project through the Mars Exploration Program under Grant NNH10CC04C.
- Language
- English
- Date published
- 02/28/2025
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984792368102771
Metrics
2 Record Views