ELECTROSTATIC PARTICLE-IN-CELL SIMULATION TECHNIQUE FOR QUASI-NEUTRALPLASMA

We have developed a simulation method with both electrons and ions rep resented as particles-in-cell, In which the electrostatic field is det ermined from the requirement of quasineutrality rather than from Poiss on's equation. This approach permits self-consistent calculation of th e potential, in quasineutral situations where statistical fluctuations in the charge density frustrate the use of Poisson's equation. Time s teps may be orders of magnitude longer than the plasma period, and mes h cells orders or magnitude longer than the Debye length, since electr on plasma oscillations do not appear in the model and the Debye length is essentially set to zero. The simulation technique correctly repres ents kinetic features such as electron and ion Landau damping. The met hod is demonstrated by application to several simple test problems, in cluding free expansion of a plasma, and linear and nonlinear ion sound . In the case of a plasma with strongly magnetized electrons, we apply the technique to determine the parallel electric field and parallel t ransport within the plasma. Quasineutral techniques for representing c ross-held transport. and edge effects in bounded plasmas, will be disc ussed in subsequent publications. (C) 1997 Academic Press.