A δf particle method for gyrokinetic simulations with kinetic electrons and electromagnetic perturbations

A deltaf particle simulation method is developed for solving the gyrokinetic-Maxwell system of equations that describes turbulence and anomalous transport in toroidally confined plasmas. A generalized split-weight scheme is used to overcome the constraint on the time step due to fast parallel motion of the electrons. The inaccuracy problem at high plasma beta is solved by using the same marker particle distribution as is used for deltaf to evaluate the betam(i)/m(e)Aparallel to term in Ampere's equation, which is solved iteratively. The algorithm is implemented in three-dimensional toroidal geometry using field-line-following coordinates. Also discussed is the implementation of electron-ion collisional effects which are important when kinetic electron physics is included. Linear benchmarks in toroidal geometry are presented for moderate beta, that is, beta much less than 1, but betam(i)/m(c) much greater than 1. Nonlinear simulation results with moderate beta are also presented. (C) 2003 Elsevier Science B.V. All rights reserved.