Benchmarks of KIPP: Vlasov-Fokker-Planck code for parallel plasma transport in the SOL and divertor

Benchmarks of the new 1D2V kinetic code KIPP (KInetic code for Plasma Periphery) for parallel plasma transport in the scrape-off layer (SOL) and divertor of magnetic confinement fusion devices are presented. The code is based on the continuum discretisation scheme for the Vlasov-Fokker-Planck equation. It assumes plasma quasi-neutrality, maintained by the electron parallel momentum balance, and uses a logical sheath boundary condition for the Debye potential drop at material surfaces. The code is parallelized under the MPI environment, with the most time consuming part, Coulomb collisions, being calculated simultaneously for all spatial locations by separate processors using a sparse matrix solver for the full non-linear collision operator in two velocity variables: parallel and gyro-averaged perpendicular velocities. KIPP is being developed with the aim of integrating it into SOLPS (B2-Eirene), to replace fluid treatment of parallel plasma transport with the kinetic one. Benchmark results for parallel electron heat conduction and electron-ion thermoforce for highly collisional plasmas are presented, as well as some results for less collisional plasmas. This paper focuses on the 1d2v features of the code, with the 0d2v features presented earlier in [1, 2]. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)