Magnetic Reconnection in the Ionosphere of Mars: The Role of Collisions

Abstract:

Ion loss from planets, and thus atmospheric loss overall, depends on the planet’s magnetic field and whether it is induced in the ionosphere (like Venus) or intrinsic (like Earth). Both induced and intrinsic magnetic fields play a role at Mars, due to crustal magnetic fields in the Southern Hemisphere. How the fields induced in the ionosphere by the solar wind interact with the intrinsic field is important for the ionospheric dynamics and ion loss. This presentation will consider the role of magnetic reconnection in the dayside ionosphere of Mars in the collisional regime and present some relevant data from the MAVEN (Mars Atmosphere and Volatile EvolutioN) mission. Reconnection should occur where the induced fields and plasma push against plasma controlled by crustal fields. Magnetic reconnection is associated with topological changes in the magnetic field and is also a source of energy for the plasma, and can thus affect the ionospheric dynamics and ion loss at Mars. Both theoretical concepts and MAVEN particle and field data from several instruments will be considered.