Journal article
The Ionopause at Mars and Its Correlation With Magnetic Topology and Plasma Pressure
Journal of geophysical research. Space physics, Vol.130(7), e2024JA032922
07/2025
DOI: 10.1029/2024JA032922
Abstract
We utilize Mars Atmosphere and Volatile Evolution (MAVEN) observations to investigate the ionopause boundary at Mars, the formation process of which is not yet well described. We focus on the eighth deep dip campaign (DD8), which consists of 50 consecutive orbits, and we develop an automated routine to identify ionopause boundaries in electron density and temperature data. We find ionopause boundaries in 54 out of 100 ionospheric crossings and an average ionopause altitude of 368 km. Having detected the ionopause boundaries, we then examine in detail all the DD8 orbits using complementary observations from several MAVEN instruments. We show examples of two orbits, illustrating how the shapes of the topside ionosphere and ionopause can differ among ionospheric crossings and how the ionopause formation is correlated with changes in magnetic topology and the plasma pressure balance between the ionosphere and the magnetic pile‐up region (MPR). We find that 70% of the detected ionopauses are formed where there are changes in magnetic topology, particularly from closed to either open or draped magnetic field lines, and 80% of the boundaries are also formed where the ionospheric plasma pressure becomes equal to the plasma pressure of the MPR. Finally, we confirm that the ionopause boundary is more likely to be formed under high solar wind dynamic pressure conditions.
At unmagnetized or weakly magnetized planets, such as Venus and Mars, there is often a boundary formed, called the ionopause, which so far has been identified as sharp gradients in electron or ion densities. This boundary separates plasma of planetary origin from the solar wind. We utilize Mars Atmosphere and Volatile Evolution (MAVEN) data from 50 consecutive orbits and develop an automated routine to identify ionopause‐like boundaries based on sharp gradients in electron density and temperature. We then examine the regions near the identified boundaries by utilizing additional measurements from several instruments on board MAVEN. We show that there is a correlation between the location where the ionopause is formed and changes in the morphology of the magnetic field lines, as well as a correlation with pressure balance points between the plasma pressure of the ionosphere and the plasma pressure of the magnetic pile‐up region.
We identify ionopause‐like boundaries in the Martian dayside ionosphere via an automated routine, utilizing Mars Atmosphere and Volatile Evolution Langmuir Probe and Waves data We find a correlation between the ionopause and changes in the magnetic topology The ionopause is correlated with the location where there is plasma pressure balance between the ionosphere and the magnetic pile‐up region
Details
- Title: Subtitle
- The Ionopause at Mars and Its Correlation With Magnetic Topology and Plasma Pressure
- Creators
- Katerina Stergiopoulou - University of LeicesterBeatriz Sánchez-Cano - University of LeicesterMark Lester - University of LeicesterChristopher M. Fowler - West Virginia UniversityDavid J. Andrews - Swedish Institute of Space PhysicsShaosui Xu - University of California, BerkeleyNiklas J. T. Edberg - Swedish Institute of Space PhysicsSimon Joyce - University of LeicesterMats Holmström - Swedish Institute of Space PhysicsJasper S. Halekas - University of IowaDikshita Meggi - University of LeicesterAnna K. Turner - West Virginia UniversityJacob R. Gruesbeck - Goddard Space Flight Center
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.130(7), e2024JA032922
- DOI
- 10.1029/2024JA032922
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Publisher
- AMER GEOPHYSICAL UNION
- Grant note
- UK-STFC grant: ST/W00089X/1, ST/V004115/1 Royal Society International Exchanges Scheme 2022MAVEN projectNASA through the Mars Exploration Program
K.S and M.L. acknowledge support through UK-STFC grant ST/W00089X/1. B.S.-C. acknowledge support through UK-STFC Ernest Rutherford Fellowship ST/V004115/1. This project has been done thanks to the Royal Society International Exchanges Scheme 2022 that has allowed a fruitful collaboration between the University of Leicester and West Virginia University (IES\ ${\backslash}$R3\ ${\backslash}$223148). SX acknowledges support from the MAVEN project. The MAVEN project is supported by NASA through the Mars Exploration Program.
- Language
- English
- Date published
- 07/2025
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984843242202771
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