Comparison of collision treatment methods in PIC-MC plasma simulation

There exists a demand of using plasma systems at higher pressures. Unfortunately, till now there does not exist a complete theory of plasma-solid interaction for such conditions. The problem is in the effect of collisions among plasma particles. Therefore the correct treatment of collisions in computer simulations is very important. Commonly used PIC-MC technique usually uses collision treatment method based on random free path. In this contribution it is shown how this method can affect the velocity distributions of particles and in this way the whole studied system. Then another approach is suggested. Differences of results for these two methods are discussed for the case of study of sheath formation.