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Integration of DEMO-relevant PFCs and High Performance Core Plasmas. G.R. Tynan UCSD. CORE Plasma Requirements High beta ( b N >4) High confinement High bootstrap current fraction (f BS ~80-90%) with good profile alignment Steady-state operation Density and temperature profile control
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Integration of DEMO-relevant PFCs and High Performance Core Plasmas G.R. Tynan UCSD
CORE Plasma Requirements High beta (bN>4) High confinement High bootstrap current fraction (fBS~80-90%) with good profile alignment Steady-state operation Density and temperature profile control Disruption avoidance and mitigation Maximum neutron wall loading ~3MW/m2 and maximum chamber wall surface heat flux 0.5-0.6 MW/m2, PFC Requirements Actively cooled steady state with high heat flux removal (>10 MW/m2 in the divertor) Low impurity accumulation in the core plasma Acceptable accumulation of T inventory Ability to withstand and recover from extreme transient thermal loads Adequate core radiation to distribute the transport power I. The Issue: How to Produce High Performance DEMO-relevant Core Plasmas with DEMO Relevant PFCs? DEMO Requires Integration
Transient High Performance Achieved With Wall Conditioning ALCATOR C-MOD Lipschultz et al PoP 2006
Why Is This Issue Important Now? • It Can Determine Mission Success & Catastrophic Device Failure • DEMO Requires Steady-state PFC Technologies Which Do Not Exist • We Cannot Predict Behavior of a New PFC/Plasma Combination • Therefore Existing Experiments Cannot Be Extrapolated IMPLICATION: WE DO NOT KNOW HOW TO BUILD DEMO’s PFCs NOR CAN WE PREDICT DEMO PLASMA PERFORMANCE WITH EXISTING OR PLANNED EXPERIMENTS
How Should This Issue Be Resolved? • Re-create Serious Fusion Technology Program Focused on Materials, Integration • Focus Existing & Near-term New Experimental Effort on Understanding PFC/Plasma Integration Physics • Plan for a New Confinement Experiment Focused on Integration (Can It Be Done in Non-nuclear Environment?) • Execute This Experiment Once Promising Technologies Emerge