The Split-weight Particle Simulation Scheme for Plasmas

An efficient numerical method for treating electrons in magnetized plasmas has been developed. The scheme, which is based on the perturbative (delta f) gyrokinetic particle simulation, splits the particle electron responses into adiabatic and non-adiabatic parts. The former is incorporated into the gyrokinetic Poisson's equation, while the latter is calculated dynamically with the aid of the charge conservation equation. The new scheme affords us the possibility of suppressing unwanted high frequency oscillations and, in the meantime, relaxing the Courant condition for the thermal particles moving in the parallel direction. It is most useful for studying low-frequency phenomena in plasmas. As an example, one-dimensional drift wave simulation has been carried out using the scheme and the results are presented in the paper. This methodology can easily be generalized to problems in three-dimensional toroidal geometry as well as those in unmagnetized plasmas