Strategies for reaching high density and opacity conditions leveraging the Shape and Volume Rise divertor on DIII-D
POSTER
Abstract
A new divertor has been installed on the DIII-D tokamak called the "Shape and Volume Rise" divertor, which allows access to larger volume and higher triangularity plasmas. A significant experimental thrust leverages this new divertor geometry to access reactor relevant conditions of simultaneous high pressure, density, and opacity with a pedestal limited by peeling instabilities. Pushing to this new regime is an important step towards closing the Integrated Tokamak Exhaust and Performance (ITEP) gap required to extrapolate present regimes to future devices. Experiments were performed on DIII-D to 1) characterize pumping efficiency in the new divertor, 2) develop a high density, high performance ELMy H-mode regime in the super H-mode channel, 3) develop a non-ELMing quiescent H-mode regime in the super H-mode channel, 4) assess trade-offs in dRsep and triangularity for super H-mode channel access and RMP ELM suppression, and 5) scan shapes to validate EPED and ELITE modeling predicting access to these high density and high pressure pedestal conditions. This poster overviews results of these team experiments with an emphasis on the impact on core-edge integration and pedestal stability.
*Work supported by the U.S. Department of Energy under DE-FC02-04ER54698, DE-SC0014264, DE-SC0019302, DE-AC52-07NA27344, DE-AC02-09CH11466, DE-SC0022270, DE-AC05-00OR22725
Presenters
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Theresa M Wilks
- MIT Plasma Science and Fusion Center
- MIT-PSFC