Recent advances in nonlinear gyrokinetic PIC simulations in tokamak geometry

Bottino, A.*; Angelino, P.*; Allfrey, S. J.*; Brunner, S.*; Hatzky, R.*; Idomura, Yasuhiro   ; Jolliet, S.*; Sauter, O.*; Tran, T. M.*; Villard, L.*

The global nonlinear electrostatic PIC code ORB5 solves the gyrokinetic Vlasov-Poisson system assuming adiabatic electrons in realistic tokamak magnetohydrodynamic (MHD) equilibria. The present version of ORB5 shows remarkable particle and energy conservation properties and can be used for physics studies in toroidal geometry. In particular, the optimized tracer loading method has been adapted to tokamak geometry and implemented in ORB5 together with a new adaptive gyro-average algorithm. Basic physical conservation properties (energy and particle number) are used as indicators of the quality of the numerical simulations. In this paper we present the first nonlinear results of electrostatic collisionless microinstabilities of realistic MHD shaped equilibria, provided by the MHD equilibrium code CHEASE, including the toroidicity induced geometrical coupling of the zonal ExB flow and the parallel velocity nonlinearlity.