A VLASOV PARTICLE ION ZERO MASS ELECTRON MODEL FOR PLASMA SIMULATIONS

We have extended a particle-MHD model of discrete fluid ions and massless fluid electrons to the fully kinetic ions and massless fluid electrons so that such important kinetic effects, e.g., the finite Larmor radius effects, are incorporated; 2D as well as 3D versions exist. As a result the model now exhibits ion Bernstein waves. We have also developed a linear theory of the model and obtained the linear dispersion relation. The dispersion relation is in excellent agreement with results from the model. Two important improvements in numerical procedures have been implemented; the first is the elimination of unphysical short wavelength disturbances by a smoothing technique; the second is the implementation of the Richardson extrapolation (extrapolation to Δt = 0) technique in the velocity difference equations. These improvements increased the range of stability of the code greatly and enabled us to use time steps which are 10 times larger. As one application, we use the model to simulate the interaction of a neutral gas and an ambient plasma and observe the generation of waves with frequencies at integral as well as half-integral ion cyclotron harmonics for all k in accordance with some recent experimental observations in the JET tokamak. © 1992.