UC Berkeley

We investigate how the Martian dayside ionospheric structure is modified by crustal magnetic field (CMF) strength and upstream solar wind pressure by analyzing electron density data from the Langmuir Probe and Waves instrument onboard the MAVEN (Mars Atmosphere and Volatile EvolutioN) spacecraft. We find that the electron density above the exobase is anticorrelated with the ratio of solar winds normal dynamic pressure ( P SW ⊥ ) to CMF magnetic pressure ( P CMF ). We also analyze the electron density behavior across different magnetic topologies as a function of P SW ⊥ / P CMF . The extremely low electron density in the draped topology relates to ionopause-like structures. The lower electron density in the closed and open topology under higher P SW ⊥ / P CMF may be attributed to a downward force, potentially the J × B force in the case of closed topology. This study highlights the complex interplay between solar wind and CMF in influencing the Martian dayside upper ionosphere.