Magnetohydrodynamic Simulations of the Solar Wind Interaction with Mars

Present day Mars is known to be a planet devoid of any intrinsic global dipolar field due to the absence of a "once active" dynamo process that existed billions of years ago. The lack of proper magnetic shielding led to the erosion of the Martian atmosphere mediated by solar wind interactions, thereby impacting the habitability of the planet. Since the dawn of space age, there have been numerous missions devoted to the exploration of the Martian environment to understand its evolution and current conditions. In the present study, we carry out three dimensional compressible magnetohydrodynamic simulations of the interactions between solar wind and a Mars-like planet using the Star Planet Interaction Module (CESSI-SPIM) developed at CESSI, IISER Kolkata. We ignore the presence of remnant crustal fields and take precautions for not allowing any undesirable numerical outflows from the planet by using gravitational stratification. The mechanism of formation of an imposed magnetosphere around the planet is presented in detail with emphasis on magnetic reconnections that lead to the same. The pile up of stellar magnetic field on the day side of the planet, which is responsible for the induction of magnetosphere, may be inhibited if the planet hosts even a weak dipolar field. The structures of the bow shock, magnetotail and magnetic pile up region are found to be in good agreement with observational data from missions such as Phobos, Mars Global Surveyor (MGS) and Mars Atmosphere and Volatile Evolution (MAVEN). The results presented are not only applicable to planets and moons in our solar system but also provide important insight for the exploration of habitable planets in far out exoplanetary systems.