Abstract Details
Abstracts
Author: Atul Kumar
Requested Type: Poster
Submitted: 2024-04-11 12:28:06
Co-authors: S. Islam, W. Tierens, G. Dhamale, C. Lau, J. Lore, J. Rapp
Contact Info:
Oak Ridge National Laboratory
Bldg. 7601, M50, Oak Ridge Nat
Oak Ridge, TN 37831
USA
Abstract Text:
Proto-MPEX is an existing linear device, the prototype of the Material Plasma Exposure eXperiment (MPEX). The latter is currently under construction at ORNL to address the challenges of plasma-material interactions (PMI) in a high duty-cycle and safe operating fusion reactor. In this work, a coupled SOLPS-COMSO-GITR workflow, which we call “Simulated Transport of RF Impurity Production and Emission (STRIPE)”, has been employed to study the erosion and redeposition of Al impurities in Proto-MPEX. Recent experimental studies on the Proto-MPEX, have found significant amount of impurities, generated from the helicon window, deposit at the target for helicon-only conditions [Beers et. al, Phys. Plasmas, 2021]. This study investigates impurity release and its transport in Proto-MPEX with its two - electron cyclotron and ion cyclotron radiofrequency (ICRF) based auxiliary heating scenarios. Increased edge temperature due to the EC heating leads to an increased ionization in the periphery of the device. This along with the strong parallel transport and temperature screening effect due to the overall increase in plasma temperature, has found to significantly reduce the radial movement of Al-impurity and thereby, its transport towards Proto-MPX target (located in the small central region with radius of 0.06m whereas the Proto-MPEX geometry radius is 0.1m). Furthermore, a shorter connection length between the target and the ICRF-antenna also reduces the radial impurity transport and leads to the avoidance of impurity deposition at the target. Overall, these findings provide possible means to mitigate impurity transport towards the target in the MPEX device during EC and ICRF heating operation which is also a desirable goal of MPEX for PMI studies with reactor relevant plasma fluences.
Acknowledgement: Research supported by supported by the Office of Science of the U.S. DoE under Contract No. DE-AC05-00OR22725.
Comments:
Physics of the plasma edge and divertor region, including plasma surface interactions