Friday, September 30, 2022
Abstract: DIII-D experiments assess compatibility of Super H-mode (SH) pedestals with high divertor radiation using advanced feedback algorithms for density and radiated power control with impurity seeding. The SH regime, with a current-limited pedestal, allows co-optimization of important parameters for future devices such as pedestal pressure, collisionality and separatrix density. Four optimization avenues for core edge integration have been developed: 1) divertor-focused solution with nitrogen seeded partially detached plasmas in an open divertor with ~25% degradation to core performance; 2) high recycling open divertor at the onset of detachment with modest penalties (<5%) to core performance, 80% radiated power fraction, 3) closed divertor SH plasmas at detachment onset, and 4) core-focused solution with a modestly cooled, attached open divertor. The high recycling divertor at detachment onset maximizes confinement on closed flux surfaces while providing a target plasma for testing high heat flux scenarios on various divertor configurations. The SH pedestal in the closed divertor is more resilient to deuterium puffing than the open divertor, showing less degradation with increased gas. EPED pedestal predictions are consistent with experimental pedestal stability, but work is needed to extend stationarity.
BIO: Dr. Theresa Wilks is a research scientist in the field of fusion science and technology using magnetic confinement of plasmas with a focus towards energy production. As a researcher for the Massachusetts Institute of Technology, Theresa's research concerns understanding and mitigating tokamak edge transient events, developing integrated tokamak scenarios viable to be projected to future power producing devices, and diagnostic development for vacuum ultraviolet spectroscopy. She collaborates with the experimental group working on the DIII-D fusion experiment, where she is a physics operator supporting a broad range of physics objectives. She is a member of the executive committees for the US Transport Taskforce and the University Fusion Association, as well as actively participates in the APS Division of Plasma Physics in both scientific research and mentorship programs.