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22-27 October 2018
Mahatma Mandir Conference Centre
Asia/Kolkata timezone

High Fusion Performance in Super H-Mode Experiments on Alcator C-Mod and DIII-D

24 Oct 2018, 11:45
Mahatma Mandir Conference Centre

Mahatma Mandir Conference Centre

Gandhinagar (nearest Airport: Ahmedabad), India
Oral EXS - Magnetic Confinement Experiments: Stability EX/2 Pedestal & ELM Optimization


Dr Philip Snyder (General Atomics)


The “Super H-mode” regime is predicted to enable pedestal height and fusion performance substantially higher than for standard H-mode operation. This regime exists due to a bifurcation of the pedestal pressure, as a function of density, that occurs in strongly shaped plasmas above a critical density. Experiments on Alcator C-Mod and DIII-D have achieved access to the Super H-Mode regime, and obtained very high pedestal pressure, including the highest pedestal pressure ever achieved on a tokamak ($p_{ped}$~80kPa) in C-Mod experiments operating near the ITER magnetic field. DIII-D Super H experiments have demonstrated high performance, including the highest stored energy in the present configuration of DIII-D (W~2.2-3.1MJ), while utilizing only about half of the available heating power ($P_{heat}$~6-12 MW). These DIII-D experiments have achieved the highest value of peak fusion gain, $Q_{DT,equiv}$~0.5, ever achieved on a medium scale (R<2m) tokamak. Sustained, stationary high performance operation has been achieved utilizing n=3 magnetic perturbations for density and impurity control. Super H-Mode access is predicted for ITER and expected, based on both theoretical prediction and observed normalized performance, to enable ITER to achieve its performance goals (Q=10) at Ip < 15MA, and to enable more compact, cost effective DEMO designs. We present extensive comparisons of Super H theory to experiments on C-Mod and DIII-D, predictions for Super H access on JET, JT-60SA & ITER, and coupled core-pedestal predictions of fusion performance on existing and future devices. This work was supported in part by the US Department of Energy under DE-FG03-95ER54309, DE-FC02-99ER54512, DE-FC02-04ER54698, and DE-FC02-06ER54873.
Country or International Organization United States of America
Paper Number EX/2-4

Primary author

Dr Philip Snyder (General Atomics)


Dr Amanda Hubbard (MIT PSFC) Dr Brian LaBombard (MIT PSFC) Dr Carlos Paz-Soldan (General Atomics) Dr David Eldon (General Atomics) Dr Florian Laggner (Princeton University) Prof. Howard Wilson (University of York) Dr Jerry Hughes (MIT PSFC) Mr Matthias Knolker (Princeton University) Dr Orso Meneghini (General Atomics) Dr Richard Groebner (General Atomics) Prof. Saskia Mordijck (College of William and Mary) Dr Steve Scott (PPPL) Dr Ted Golfinopoulos (MIT PSFC) Dr Todd Evans (General Atomics) Dr Tom Osborne (General Atomics) Dr Wayne Solomon (General Atomics) Dr Yubao Zhu (University of California, Irvine)

Presentation Materials