NEUTRAL TRANSPORT IN HIGH PLASMA-DENSITY REACTORS

The direct simulation Monte Carlo method is used to study neutral spec ies transport in cylindrical, high plasma-density systems. This techni que is well suited for the transition flow regime in which these react ors operate. The ground state neutral density is depleted in the volum e of the chamber due to ionization and is enhanced at bounding walls d ue to ion-electron surface recombination. In addition, electron-neutra l and ion-neutral collisions heat the neutrals resulting in further ne utral density depletion. The influence of chamber geometry and fractio nal degree of ionization on neutral density profiles is explored for a n electron cyclotron resonance system. Results for an extended source/ downstream chamber and for a compact source chamber are compared.