Gyrokinetic Full f Modelling of Plasma Turbulence in Tokamaks

Understanding turbulence in fusion plasmas has become a crucial task in order to achieve sufficient confinement level in large-scale devices like ITER. The ELMFIRE full f nonlinear gyrokinetic simulation code has been developed for calculation of plasma evolution and dynamics of turbulence in tokamak geometry. Code ELMFIRE is based on a particle-in-cell algorithm with direct implicit treatment of ion polarization and consideration of either kinetic or adiabatic electrons, and also impurities. The gyrokinetic model performs averages over the gyro-orbits while keeping accuracy over the most interesting time and length-scales regarding turbulence development. Opposite to delta f algorithms, the full f method is suitable for calculating also strongly perturbed plasmas including wide orbit effects, steep gradients and rapid dynamic changes. ELMFIRE is here been tested against the neoclassical theory, and used for computation of the neoclassical radial electric field and the influence of turbulence on that magnitude.