Abstract Details
| status: | file name: | submitted: | by: |
|---|---|---|---|
| approved | sherwood2025_abstract_kumar_atul.pdf | 2025-03-13 17:08:05 | Atul Kumar |
Abstracts
Author: Atul Kumar
Requested Type: Poster
Submitted: 2025-03-13 17:06:22
Co-authors: W. Tierens, J. Lore, M. Shafer, B. Van Compernolle, R. I. Pinsker, D. Nath, M. Shephard and, O. Sahni
Contact Info:
Oak Ridge National laboratory
1 Bethel Valley Rd
Oak Ridge, TN 37830
USA
Abstract Text:
The DIII-D tokamak recently achieved high-power helicon wave operation for the first time in any tokamak, coupling approximately 360 kW RF power at 476 MHz into L-mode plasmas using a traveling-wave antenna. While RF power is essential for plasma heating and current drive, enhanced plasma-material interactions (PMI) due to sheath rectification can induce large RF-driven voltages on antenna structures, leading to significant material erosion. To investigate PMI at the helicon antenna, we employ the Simulated Transport of RF Impurity Production and Emission (STRIPE) framework, which integrates multiple computational tools, including SOLPS, COMSOL, RustBCA, and GITR(m), to model impurity transport, erosion, and deposition. Using DIII-D discharge #195196, STRIPE simulations assess RF sheath-driven impurity generation and predict net erosion and redeposition profiles while accounting for self-sputtering effects that influence material lifetime. A parametric scan of plasma density and helicon power reveals that erosion fluxes are strongly dependent on plasma density but weakly influenced by helicon power under DIII-D conditions. The simulations indicate that the helicon discharge was operated in a density regime with low rectified sheath voltages and minimal impurity sputtering, consistent with low impurity radiation measurements. These findings provide insights into the effects of helicon waves on PMI, helping to identify favorable and limiting operational regimes for DIII-D and other tokamaks, offering guidance for optimizing RF heating and current drive while minimizing material erosion and impurity transport. Work supported by the US Department of Energy under Contract No. DE-AC05-00OR22725 and DE-FC02-04ER54698. References: Pinsker, R.I., et al., First high-power helicon results from DIII-D, Nuclear Fusion, 2024. Kumar, A., et al., Integrated modeling of RF-Induced Tungsten Erosion at ICRH Antenna Structures in the WEST Tokamak, arXiv:2412.08748v1, 2025.
Characterization: 3.0
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