دانلود رایگان مقاله شبیه سازی PIC / MCC تخلیه ظرفیتی همراه

Abstract

A PIC/MCC simulation model for the analysis of low-temperature discharge plasmas is represented which takes the common leapfrog and the velocity Verlet algorithm for the particle integration, adaptive particle management as well as parallel computing using MPI into account. Main features of the model including the impact of super particle numbers, adaptive particle management and the time step size for the different integration methods are represented. The investigations are performed for low-pressure capacitively coupled radio frequency discharges in helium and argon. Besides a code verification by comparison with benchmark simulation results in helium it is shown that an adaptive particle management is particularly suitable for the simulation of discharges at elevated pressures where boundary effects and processes in the sheath regions are important. Furthermore, it is pointed out that the velocity Verlet integration scheme allows to speed up the PIC/MCC simulations compared to the leapfrog method because it makes the use of larger time steps at the same accuracy possible.

5. Summary

A PIC/MCC code for the simulation of low-temperature gas discharge plasmas was introduced. It includes the common leapfrog and the velocity Verlet integration method for integrating Newton’s equations of motion for electrons and ions, an adaptive particle management to adjust the weight of super particles and parallel computing using MPI. Main features of the simulation tool were represented and differences between the particle integration methods were discussed. The present PIC/MCC simulation method was applied to studies of CCRF discharges in helium and argon. The comparison with corresponding benchmark simulation results reported in [18] demonstrated well the accuracy and applicability of the code. It was particularly shown that the results obtained with and without APM converge to the same solution if the number super particles per cell is large enough. It was pointed out that the application of the present APM algorithm can be disadvantageous regarding the accuracy of the model for a given total number of super particles in case that only processes in the plasma bulk determine the plasma properties and the sheath regions are of minor importance. Furthermore, the comparison of the results obtained from the leapfrog and velocity Verlet integration method for different time step sizes suggests the use of the velocity Verlet particle integration method for the simulation of discharge plasmas because it allows for larger time step sizes than the leapfrog algorithm at appropriate accuracy of simulations. The comparative studies also pointed out that the comparison with benchmark results requires special care, if the results are not converged with respect to certain numerical parameters or different methods are employed.