We are often asked by potential customers, where the electron Monte Carlo approach implemented in HPEM and accessible via QVT gives an advantage in modelling plasma? Why not just use a fluid model alone?
|Fluid Model||Monte Carlo|
|Electron Temperature||Calculated by the electron energy balance equation implying Maxwellian EEDFs||Obtained from the spatially resolved EEDFs. Accounts for non-Maxwellian EEDFs|
|Electron Impact Rates||Rates are calculated from EEDFs obtained from a global Boltzmann - Solver. Local rates are assigned according to the local electron temperature. This does somewhat account for non-Maxwellian EEDFs, however, the influence of, for example, high energy electrons in the bulk created by sheath interactions are not covered.||Rates are calculated from the spatially resolved EEDFs. This does take non-local effects such as high energy electrons created in the sheath region penetrating into the plasma bulk into account.
|Transport Parameters||The diffusion coefficient and mobility are calculated using the local electron temperature and corresponding collision frequency from global EEDF||The diffusion coefficient and mobility are calculated using the electron temperature and collision frequency obtained from the spatially resolved EEDFs
|Conclusion||The fluid model has only limited abilities to take non-local effects and non-Maxwellian effects into account. An example is high energy electrons created in the sheath region travelling into the bulk as they are observed in low pressure CCPs.||All parameters used in the fluid model are directly derived from the actual, spatially derived EEDFs taking non-local effects and non-Maxwellian EEDFs fully into account.|