Séminaire Lagrange - Antoine Riols

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Turbulence and gravitational instability in accretion discs / mardi 7 février 2017, 10h30, NEF - Mont Gros - CION - talk in english - retransmis à Valrose

26-01-2017

Accretion discs are among the most intriguing and fascinating structures in the Universe. The physical processes governing their short and long-term evolution are still not well understood, as well as their sability to form and host planets. The turbulence in such objects is thought to play a major role and could be induced by a large spectrum of instabilities. I will review here one of this instability, the gravitational instability (GI), which might be also active in galaxies and star formation regions. I will show that it features in many fundamental processes like angular momentum transport, fragmentation, and outbursts exemplified by FU Ori and EX Lupi systems. Via a suite of MHD numerical simulations in the shearing box, I will investigate in particular the impact of a magnetic field in the saturation of the gravitational instability and show how the fragmentation criterion for giant gaseous planets formation might be affected by such magnetic field

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