Energy conversion mechanisms in space plasmas

Student : DAHANI Souhail

Advisor : GÉNOT Vincent and LAVRAUD Benoit

Start : October 2021

Group : PEPS

The conversion of energy in space plasmas has major consequences visible in the first place at large spatial scales, with for example energy transfers through planetary shocks (conversion of kinetic energy into thermal and magnetic energies) or else at various boundaries through magnetic reconnection (conversion of magnetic energy into kinetic and thermal energies). Yet it is increasingly clear that this conversion operates on small spatial scales through processes often involving both shocks, magnetic reconnection and turbulence. Recent satellite observations have indeed shown that the crucial elements of these processes are the current layers or sheets, which are a privileged location for energy dissipation. The proposed thesis will be based on data from several space missions, mainly in the solar wind and the terrestrial magnetosheath, to quantify the energy conversion at the levels of these current layers. On the one hand, the MMS mission offers an unequaled multipoint data set in terms of spatial and temporal resolutions, which makes it possible to solve the electronic physics in the magnetosheath and at the magnetopause. On the other hand, the Solar Orbiter mission has been obtaining data for 1 year which opens a new window on the kinetic physics of the solar wind. These detailed data make it possible to analyze the microphysics of energy exchanges by solving the different terms of the energy equations in fluid or kinetic formalisms. This observational work will be compared with the results of numerical simulations in similar contexts.

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