Pedestal Structure in DIII-D Steady-State Discharges
Abstract
A range of DIII-D steady-state discharges have been analyzed to determine the pedestal structure and bootstrap current as a function of several global parameters including qmin) , q95 and βN. The pedestal structures are compared with EPED predictions. Variations in turbulence, E × B shearing rate, jBS and MHD stability are examined. DIII-D is developing candidate high-βN steady-state operational scenarios, including high-qmin) and high-li, through current and pressure profile optimization. Pedestal structure and how it affects the current profile is important for any sustained high performance scenario. High-qmin) scenarios require a relatively large pedestal height with significant bootstrap current, while high-li scenarios require a smaller pedestal and reduced bootstrap current. Understanding how the pedestal structure is affected by the other requirements of operating in these scenarios is needed for this optimization.
Work supported by the US Department of Energy under DE-AC05-00OR22725, DE-FC02-04ER54698, and DE-AC52-07NA27344.- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- October 2013
- Bibcode:
- 2013APS..DPPUP8048S