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    Jeudi 5 octobre 2017 14:00-15:00 - Ronan Modolo - LATMOS, UVSQ

    R. Modolo : A global model for Solar wind - Mars interaction

    Résumé : Since the sixties several planetary missions have explored the neutral and ionized environment of Mars and have led to a comprehensive picture of Mars’ atmosphere/ionosphere/solar wind coupling. The interaction of the Solar Wind with Mars clearly contributes to the erosion of the gaseous envelop and has potentially an important impact on the atmospheric evolution of the planet. The electromagnetic coupling with the Martian atmosphere takes place through ionization processes : ionization by solar photons, electron impact ionization (incident plasma electrons ionize the upper atmosphere), and charge exchange between ionized and neutral particles producing a cold ion and a fast neutral. Since September 2014, MAVEN spacecraft has been observing the Martian upper atmosphere and its interaction with the solar wind [Jakosky et al., 2015]. One of the main goal of the mission is to determine the role that loss to space of volatiles from the Mars atmosphere has played along Mars’ history. Modelling e-fforts have been conducted to support the analysis of in situ measurements and to understand the impact of specifi-c parameters (solar EUV, dynamic pressure,...) on the Martian environment. Global simulation models of Mars’ interaction with the solar wind have been developped with various formalisms since the 80’s. A three-dimensional multi-species hybrid model dedicated to the description of the plasma dynamic induced by Mars’ interaction with the solar wind was developped few years ago [Modolo et al., 2005, 2006]. This approach, based on a kinetic description of the ions and a fluid description of the electrons, takes into account self-consistently the Hall term which breaks the symmetry of the system. Recently a modelling eff-ort have been undertaken to improve the spatial resolution of the hybrid model as well as the ionospheric description leading to the LatHyS (Latmos  Hybrid Simulation) model [Modolo et al, 2016]. I will present the simulation model and its formalism, as well as a panorama of simulation results and their comparison with in situ measurements.

    Lieu : Salle G210, Bâtiment Germain.45, avenue des Etats-Unis, 78000 Versailles.

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