April 4-6

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Author: Atul Kumar
Requested Type: Poster
Submitted: 2022-03-02 15:42:12

Co-authors: J. F. Caneses Marin, C. Lau, R. Goulding

Contact Info:
Oak Ridge National Laboratory
1 Bethel Valley Road
Oak Ridge, Tennessee   37831-8
United States of Ame

Abstract Text:
The auxiliary heating schemes in the Material Plasma Exposure eXperiment (MPEX) are based on cyclotron resonance heating with radio frequency (RF) waves. Ion cyclotron heating (ICH) and electron cyclotron heating (ECH) in MPEX are used to independently heat the ions and electrons and provide fusion divertor conditions ranging from sheath-limited to fully detached divertor regimes. A Hybrid Particle-In-Cell code- PICOS++1 is developed and applied to understand the plasma parallel transport during ICRF heating in MPEX/Proto-MPEX. With this tool, evolution of the distribution function of MPEX/Proto-MPEX plasma is modelled in the presence of (1) Fokker-Planck Coulomb collisions, (2) volumetric particle sources and (3) quasi-linear RF-based ICH. In this work, the code is benchmarked against the experimental data from Proto-MPEX and simulation data from SOLPS. The experimental observation of density drop near the target in Proto-MPEX and also for MPEX during ICRF heating is demonstrated and explained quantitatively using PICOS++ modelling. Finally, a complete parametric scan of various parameters- ICH power, source rate, electron temperature and location of ICRF heating- is performed on MPEX and Proto-MPEX plasma to investigate its effects on plasma densities and flows (1) near the source (2) near ICRF antenna/central chamber, and (3) near the target location and is matched with the existing experimental data.

Acknowledgement: This research used resources of the Fusion Energy Division, FFESD at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725. This research also used resources of the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility located at Lawrence Berkeley National Laboratory

1. A. Kumar and J. F. Caneses Marin, Plasma Phys. Control. Fusion, 64 (2022), 035012