OVERVIEW OF THE DIII–D PROGRAM AND CONSTRUCTION PLANS Presented by Peter I. Petersen for the DIII–D Team 23rd Symposium on Fusion Technology 20 - 24 September 2004 - Fondazione Cini, Venice, Italy 214-04/jy

OUTLINE Advanced Tokamak Internal Coils (I-coils) Electron Cyclotron System Plasma Control System Diagnostics 2005 – 2006 Upgrades Conclusion 214-04/jy

DIII–D CAPABILITIES ALLOW A WIDE RANGE OF RESEARCH AND TECHNOLOGY ISSUES TO BE ADDRESSED 60 different diagnostics 214-04/jy

MAIN RESEARCH GOAL FOR DIII–D IS THE ADVANCED TOKAMAK, WHICH INTEGRATES MANY PHYSICS ELEMENTS 214-04/jy

TOOLS TO MINIMIZE ERROR FIELDS AND RESISTIVE WALL MODES AT HIGH PLASMA PRESSURE 6 section, external C-coil 12 section, internal I-coil 5 C-supplies each @5 kA, 350 V or 7kA at lower voltage tap 4 Switching Power Amplifiers (SPAs) each @5 kA, 300 V, ~ 4 - 5 s System must provide for both correction of error fields and feedback stabilization of the RWM. 214-04/jy

FLEXIBLE I-COIL POWER SUPPLY CONFIGURATIONS POSSIBLE WITH PATCH PANEL

I-COILS PROVIDE A FLEXIBLE SYSTEM FOR ELM CONTROL N=3 mode Small islands might be responsible for the ELM suppression Relative small impact on core confinement Enhance magnetic and density fluctuations with no indication of increased stochasticity 214-04/jy

CURRENT ECH SYSTEM ECH System Layout Gyrotron in stand ECH launcher 3 CPI gyrotrons with diamond window, 1 MW 10 s 3 Gycom gyrotrons with boron nitride window, 0.75 MW 2 s 1 MW ECH waveguide 214-04/jy

ECCD STABILIZATION OF NEO-CLASSICAL TEARING MODES Feedback system adjusts q=3/2 surface location to minimize mode amplitude Active tracking keeps ECCD at the q = 3/2 surface in the absence of the mode compensates for the Shafranov shift as the plasma pressure b increases Mode does not reappear when b is raised above the initial stability limit Stabilization of the 2/1 mode has also been done. 214-04/jy

THE LITHIUM BEAM DIAGNOSTIC USES ZEEMAN POLARIZATION SPECTROSCOPY TO MEASURE THE EDGE CURRENT DENSITY 214-04/jy

THE UPGRADED BEAM EMISSION SPECTROSCOPY (BES) DIAGNOSTIC BRINGS NEW INSIGHT INTO CORE TURBULENCE AND MHD 214-04/jy

MASSIVE GAS PUFF SUCCESFULLY MITIGATES PLASMA DISRUPTIONS Open jet (Aug. 2003) Directed jet (Mar. 2004) Directed jet w/ reduced back volume (Oct. 2004) • Pjet (r=1) ~ 0.04 atm. • Pjet (r=1) ~ 0.02 atm. • Pjet (r=1) ~ 0.04 atm. • Fast (~ 1ms) rise time • Slower (~3ms) rise time. • Medium (~ 2ms) rise. Experiments show significant (2-3x) reduction in halo currents and divertor heat loads (over VDE disruption). Large (4x) variation in thermal quench time with gas jet pressure indicates that jet design plays important role. No observed runaway electron generation (except in low pressure Ar gas puff).

INTEGRATED PLASMA CONTROL IS KEY TO THE DIII–D AT PROGRAM Real Time Feedback Controlled (Actuator, Sensor) Long experience: Global parameters and equilibrium Recent progress: Two-point Te control Under development: Real-time, multi-point profile control Te(r,t): ECH, ECE, Thomson scattering j(r,t): ECCD, MSE … Te: ECH,ECE NTM: ECCD, magnetics Disruption: Gas jet, magnetics, bolometers NBI Plasma b: Paux, RTEFIT RWM: C-Coil, I-Coil, RTEFIT Equilibrium: PF-Coils, RTEFIT Density: Pellet/Cryopumps/Gas valves, CO2 Interferometers

FLEXIBLE DIII–D PLASMA CONTROL SYSTEM SUPPORTS INTEGRATED PLASMA CONTROL 214-04/jy

PLANNED ECH UPGRADE DURING 2005 - 2006 3 CPI gyrotrons have been purchased — Delivery scheduled Jul 05 – Jan 06 — Ready for operation in May 06 1 CPI development gyrotron will be available for DIII–D FY05 1 Russian short pulse gyrotron will be available 8 operating gyrotrons might be available in May 06 but only power supplies and transmission lines for 6 214-04/jy

LOWER DIVERTOR WILL BE MODIFIED FOR DENSITY CONTROL OF HIGH TRIANGULARITY DOUBLE NULL DIVERTORS Current configuration New configuration double null shape New configuration ITER shape 214-04/jy

A BEAMLINE REVERSAL IS NECESSARY FOR NEW PHYSICS STUDIES AND IMPROVED PLASMA MEASUREMENTS QDB regime with central co-rotation Understanding physics of rotation Transport barrier control (separate ExB and Shafranov shift effects) RWM stability with low rotation NTM stabilization with modulated rf Separate Er and J(r) in MSE measurement 214-04/jy

OTHER DIII–D UPGRADES Two Cooling Tower (replace old ones) Beltbus (upgrade to 10 s) 12 audio amplifiers to stabilize RWMs 2 shown on this picture Upgrade 2 Toroidal Field Circuit Diodes (1 shown) (upgrade to 10 s) 214-04/jy

DIII–D LONG TORUS OPENING ACTIVITIES SCHEDULE 214-04/jy

OTHER DIII–D/GA PAPERS P3C-A-72 OVERVIEW OF THE DIII–D PROGRAM AND CONSTRUCTION PLANS* PETERSEN, P.I. Selected also for oral presentation O3B-A-72 P3T-B-78 THE UPGRADE OF THE DIII-D EC SYSTEM USING 120 GHZ ITER GYROTRONS CALLIS, R.W. P3T-B-246 ECH MW-LEVEL CW TRANSMISSION LINE COMPONENTS SUITABLE FOR ITER OLSTAD, R.A P3C-C-77 HIGH PERFORMANCE INTEGRATED PLASMA CONTROL IN DIII–D* HUMPHREYS, D.A. P3C-C-79 PROGRESS TOWARDS ACHIEVING PROFILE CONTROL IN THERECENTLY UPGRADED DIII-D PLASMA CONTROL SYSTEM* PENAFLOR, B.G P3C-C-149 DIII-D INTEGRATED PLASMA CONTROL TOOLS APPLIED TO NEXT GENERATION TOKAMAKS* LEUER, J.A P2C-D-80 REAL-TIME MULTIPLE NETWORKED VIEWER CAPABILITY OFTHE DIII-D EC DATA ACQUISITION SYSTEM* PONCE, D. P2T-E-81 OVERVIEW OF THE DIII–D INTERNAL RESISTIVE WALL MODE STABILIZATION POWER SUPPLY SYSTEM* SZYMANSKI, D.D P4T-G-71 STRUCTURAL UPGRADE OF IN-VESSEL CONTROL COIL ON DIII D* ANDERSON, P.M. P2C-D-251 ADVANCES IN REMOTE PARTICIPATION FOR FUSION EXPERIMENTS* SCHISSEL, D.P Selected also for oral presentation O2B-D-251 P1C-H-467 EVALUATION OF SUPER CRITICAL HELIUM AS A COOLANT FOR DIII-D TYPE CRYOCONDENSATION BAXI, C.B., 214-04/jy