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Chiffres janvier 2022

 

2018-GdT ITER - S. Colombi

Mardi 16 Janvier 2018 à 11h : Stéphane Colombi (Institut d’Astrophysique de Paris)

Solving Vlasov-Poisson equations with a “metric” approach

In this talk, after a short general introduction on Vlasov solvers, I will present a new semi-Lagrangian Vlasov-Poisson scheme, suited for describing the dynamics of warm systems such as stars in galaxies or dark matter in relaxed halos, and easily extendable to plasmas. It employs metric elements to follow locally the geometry of the flow at second order. Using a percolation algorithm in Lagrangian space to compute the region of influence of each metric element, the algorithm allows one to find quickly and accurately the initial phase-space position of any test particle. Hence, the phase-space distribution function can be reconstructed at any time from initial state by direct application of Liouville theorem. When deformation of the metric is too important, the procedure is repeated again by taking the phase-space distribution function at present time as a new initial condition.

This work is presented in details in Colombi S., Alard C., 2017, Journal of Plasma Physics 83, 705830302.