**Topic/Type**:
2.2 Kinetic methods, Particle-In-Cell and Vlasov, Poster

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Computational study of plasma-solid interaction at increasing pressures

**
S. Roucka, R. Hrach
**

*
Charles University in Prague, Faculty of Mathematics and Physics*

In the last years the challenging problem of plasma science and technology started to be the surface treatment at higher pressures. The theoretical analysis of processes in such plasmas is difficult, because the theories derived for slightly collisional plasma lose their validity at medium pressures; therefore the methods of computational physics are now being widely used. The most accurate models are self-consistent particle codes but these methods are very time-consuming and at higher pressures this disadvantage is more and more pronounced. The main problem of particle simulation at higher dimensions is the increasing amount of collisions among plasma particles, so the correct and effective treatment of collisions in computer simulation is very important. Another problem that arises during the transition to higher pressures is the influence of metastable particles.

This contribution concentrates on verifying the accuracy of Monte Carlo collision simulation and on increasing the speed of the particle-in-cell simulation at higher pressures. We present an analytical treatment of the Monte Carlo collision model and a simple improvement of the particle-in-cell Monte Carlo method that consists in allowing multiple collisions in single time step. Numerical simulations show, that this improvement can speed up the particle-in-cell simulation by an order of magnitude at higher pressures.