Bremen 2017 – scientific programme
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P: Fachverband Plasmaphysik
P 15: Helmholtz Graduate School II
P 15.5: Poster
Tuesday, March 14, 2017, 16:30–18:30, HS Foyer
Comprehensive benchmark of the ONIX code for simulating negative ion extraction from an ITER relevant ion source. — •Ivar Mauricio Montellano1, Serhiy Mochalskyy1, Adrien Revel2, Dirk Wünderlich1, and Ursel Fantz1 — 1Max- Planck-Institut für Plasmaphysik, 85748 Garching, Germany — 2LPGP, Univ. Paris-Sud, 91400 Orsay, France
The ITER NBI system is based on powerful large-scale RF sources for negative hydrogen or deuterium ions. In order to improve the insight into the complex physics of the low pressure, low temperature plasma close to the extraction system of the ion source the application of self-consistent models is mandatory. The 3D PIC code ONIX is capable to simulate the volume close to one extraction aperture of the ITER prototype source. So far, ONIX has been applied in order to reproduce the generation and extraction of negative hydrogen and of co-extracted electrons. Of particular importance is the ratio of extracted ion current to co-extracted electron current which has to be kept below one in the experiment. However, some experimental results as the presence of a significant amount of surface produced negative ions in the plasma volume cannot be reproduced by the code. This discrepancy initiated a thorough benchmarking process. Addressed during the benchmarking are the boundary conditions in the beam direction and numerical aspects, such as the ratio of the Debye length to the grid cell size used by the code. Presented are benchmark results as well as a comparison between plasma properties calculated for the prototype source using the former and the improved version based on the benchmarking results.