Ion velocity distribution functions in argon and helium discharges: detailed comparison of numerical simulation results and experimental data

Using Monte Carlo Collisions (MCC) method, we have performed simulations of ion velocity distribution functions (IVDF) taking into account both elastic collisions and charge exchange collisions of ions with atoms in uniform electric fields for argon and helium background gases. The simulation results are verified by comparison with the experiment data of the ion drift velocities and the ion transverse diffusion coefficients in argon and helium. The recently published experimental data for the first seven coefficients of the Legendre polynomial expansion of the ion energy and angular distribution functions are used to validate simulation results for IVDF. Good agreements between measured and simulated IVDFs show that the developed simulation model can be used for accurate calculations of IVDFs.