Global electromagnetic gyrokinetic simulation in 3D equilibria

Abstract

Simulations of plasma microinstabilities and related turbulence are a necessary complement to stellarator experiments as e.g. Wendelstein 7-X. Especially important are full torus simulations for three-dimensional stellarator configurations. Gyrokinetics as a first principle based theory is well suited to describe the relevant physics. An established and flexible method for solving the gyrokinetic system of equations is the simulation via the particle-in-cell (PIC) Monte-Carlo method. For this purpose the EUTERPE code has been established which originally solved the gyrokinetic equation globally in arbitrary stellarator geometry including kinetic electrons, electromagnetic perturbations (also the code includes all the nonlinear terms). With the availability of up-to-date high performance computing hardware it is thus possible to further enhance the physical content of the simulations. The full kinetic treatment of the electrons will include trapped particle effects and the inclusion of electromagnetic effects will extend the scope of applicability to the magnetohydrodynamic (MHD) regime. These developments will make EUTERPE the first code worldwide that is able to simulate global gyrokinetic electromagnetic instabilities in three dimensions. Further physics can be included by using collisions for each species. To address the important problem of the interaction of fast ions with MHD modes in a simplified way, a version of the code is under development in which the non-linear particle response is coupled to the linear MHD equations.