Implicit moment particle simulation of plasmas

It is shown that an implicit E field can be obtained from Poisson's equation with the aid of the lower two fluid moment equations, permitting stable particle simulations for ω/sub p/Δt>>1 and Δx/lambda/sub D/>>1, where ω/sub p/ and lambda/sub D/ are the plasma frequency and Debye length, respectively. In the quasi-neutral limit the effect of this E is to provide just the predicted current required to drive all present deviations in the total charge density to zero in the next cycle. In near vacuum, or with ω/sub p/Δt>>1, the field expression reduces to the standard form used with conventional leapfrog schemes. Sample applications are discussed