Section: New Results

Aligned interpolation for gyrokinetic Tokamak simulations

Participants : Guillaume Latu, Michel Mehrenberger [correspondent] , Maurizio Ottaviani, Eric Sonnendrücker.

This work is devoted to study the aligned interpolation method in semi-Lagrangian codes. The scheme is presented and algorithms used implementing the scheme are given. A theoretical justification of the method is given with convergence estimates in the simplified context of 2D constant advection, assuming stability of the scheme. The stability is here studied numerically, letting the formal proof as an open problem. The solution is successfully applied in the gyrokinetic context: first in a simplified case in cylindrical geometry and then in toroidal geometry. In the first case, the solutions provided by simulations based on the scheme are in accordance with linear dispersion analysis; in the second case, numerical simulations produced by the Gysela code are presented, simulation based on the standard scheme are compared to those based on the new aligned scheme. This work will lead to a project of paper, which will be submitted in 2016.