Global particle-in-cell simulations of microturbulence with kinetic electrons

A systematic approach (called the splitting scheme [1]) to accurately model electron kinetic effects in gyrokinetic PIC simulation is presented. The 1D application of the scheme shows that the linear properties of the simulated plasma are more accurate [1]than the conventional perturbative delta-f scheme and that the nonlinear properties are considerably improved [2] It will be shown that an accurate loading of the initial distribution function based on a neural network algorithm [3] and a noise-free collisional operator [4]for PIC codes allow for even longer simulations with good momentum and energy conservation properties. The toroidal version of the scheme, which relies on a global finite-element elliptic solver [5] is used in the GTC code [6]; preliminary results on trapped- electron mode modified ITG turbulence will be reported.\newline \newline [1]J.L.V. Lewandowski, Phys. Plasmas 8, 3204 (2003)\newline [2]J.L.V. Lewandowski, PPCF, 45, L49 (2003)\newline [3]J.L.V. Lewandowski, Phys. Lett. A, 291 (2003)\newline [4] J.L.V. Lewandowski, Phys. Plasmas 12, 2322 (2005)\newline [5] Y. Nishimura et al, submitted to JCP (2004) \newline [6] Z. Lin et al, Phys. Plasmas 6, 1857 (2000) [supported by Scidac Center for GPS project]