Speaker
Dr
Thomas Jenkins
(Tech-X Corporation)
Description
The heating of confined tokamak plasma to fusion-relevant temperatures can cause sputtering of high-Z impurities from plasma-facing components, and such impurities radiatively cool the plasma, especially as transport effects carry them to the reactor core. The sputtering process is believed to be exacerbated by the large electromagnetic fields generated by RF antennas, since these fields alter the dynamics of sheaths that form on antenna components in contact with plasma. Recent advances in finite-difference time-domain (FDTD) modeling techniques [T. G. Jenkins and D. N. Smithe, Plasma Sources Sci. Technol. 24, 015020 (2015)] enable the physics of localized sheath potentials to be modeled concurrently with the physics of antenna near- and far-field behavior and RF power flow. When implemented on high-performance computing platforms, such techniques enable the study of plasma-surface interactions in realistic experimental ion-cyclotron resonance heating scenarios at previously inaccessible levels of resolution. We will present results and 3D animations of high-performance (10k – 100k core) FDTD simulations of Alcator C-Mod's field-aligned ICRF antenna on the Titan supercomputer, considering (a) sputtering and impurity production, as driven by self-consistent sheath potentials at antenna surfaces; (b) the use of localized dielectric coating material on antenna components, as a design-based impurity mitigation strategy, and (c) the physics of slow wave excitation in the immediate vicinity of the antenna hardware and in the scrape-off layer for various edge densities.
This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences, under Award Numbers DE-FC02-08ER54953 and DE-SC0009501. This research used resources of the Oak Ridge Leadership Computing Facility 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.
| Country or International Organization | USA |
|---|---|
| Paper Number | TH/P4-34 |
Primary author
Dr
Thomas Jenkins
(Tech-X Corporation)
Co-author
Dr
David Smithe
(Tech-X Corporation)
