Solar Wind CME Impacts on the Martian Ionosphere: Insights from MAVEN Observations and ENLIL Simulations

The 77th International Astronautical Congress (IAC ), Antalya, Türkiye, 5 - 09 Ekim 2026, ss.1-15, (Tam Metin Bildiri)

This study examines how the Martian ionosphere is affected by. Three CME events that occurred on April 21–22,

2021, August 30, 2022, and May 17–18, 2024, were selected for the analysis and compared. These occurrences were

chosen because the MAVEN (Mars Atmosphere and Volatile Evolution) spacecraft was in an appropriate

observational position at the time, and they reflect large CME passages that caused notable solar wind disturbances

and dynamic pressure increases at Mars.

This study examined how the solar wind flows from the Sun to Mars' orbit using simulations of the WSA–ENLIL

heliospheric model. Data from the MAG (Magnetometer) sensor on board the MAVEN spacecraft was used to

examine fluctuations in the magnetic field surrounding Mars. Additionally, observations from the LPW (Langmuir

Probe and Waves) instrument were used to investigate changes in electron temperature and density in the Martian

ionosphere. The ionospheric plasma structure was examined in relation to the temporal fluctuations of important

solar wind parameters, including solar wind velocity, plasma density, and dynamic pressure. Additionally, SPICE

geometry data sets were used to account for geometric aspects such as the spacecraft's distance from Mars' center and

the solar zenith angle.

The obtained data were analyzed using time-series analysis and statistical methods. Time-series analysis and

statistical techniques were used to examine the collected data. Pearson correlation coefficients and correlation

matrices were computed to investigate the correlations between the parameters. Additionally, histogram analyses

were used to examine changes in parameter distributions prior to, during, and following the CME passes.

Additionally, data from the Solar Energetic Particle (SEP) detector on board MAVEN were used for analyzing

changes in energetic particle fluxes.

The findings show that the electron density and plasma properties in the Martian ionosphere have been significantly

affected by powerful CME intersections. Specifically, it was discovered that the distribution of plasma in the Martian

ionosphere was significantly impacted by increases in solar wind dynamic pressure. This study adds to an improved

comprehension of the relationship between solar wind characteristics and ionospheric changes and provides

perspectives on space weather effects at Mars through comparisons of the plasma responses generated by several

CME events in the Martian ionosphere.