Oberseminar 10/31/2011

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Marek Simon,
Max Planck Institute for Plasma Physics

Benchmark and Validation of non-linear EIRENE Monte Carlo neutral transport solver

Determination of neutral particle distributions is of great interest for the design of a fusion reactor. Unfortunately in a fusion reactor the neutral particle densities present, give rise to a collisionionalty where collisions can not be neglected but fluid descriptions fail as well. Therefore massive computational effort is required for solving the Boltzmann equation with a nonlinear collision integral. The Monte Carlo linear transport solver EIRENE represents a possibility to solve the Boltzmann equation in the BGK approximation, while being inherently parallelizable. In this thesis, the calculation of particle distributions has been validated and benchmarked by comparing conductances calculated by EIRENE with well documented cases in the literature. Conductances were calculated for rectangular orfices, tubes of different length, as well as at different pressure ratios. The agreement was found to be very good for Kn>0.1 and for some cases even Kn>0.01. In addition the existing code was extended to include a more realistic approximation of the collision integral and a first qualitative validation was performed.