GA-A21186-V£lA UC-420 Dlll-D RESEARCH OPERATIONS ANNUAL REPORT TO THE U.S. DEPARTMENT OF ENERGY OCTOBER 1, 1991 THROUGH SEPTEMBER 30, 1992 by PROJECT STAFF D. BAKER, Editor Work prepared under Department of Energy Contract DE-AC03-89ER51114 GENERAL ATOMICS PROJECTS 3466/3467/3470/3473 DATE PUBLISHED: MAY 1993 GENERAL ATOMICS * DsnwmoN OF ira DOftJflBft iTUteJMnro j^ DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. This report has been reproduced directly from the best available copy. Available to DOB and DOE contractors from the Office of Scientific and Technical Information P.O. Box 62 Oak Ridge, TN 37831 Prices available from (615) 576-8401, FTS 626-8401. Available to the public from the National Technical Information Service U.S. Department of Commerce 5285 Port Royal Rd. Springfield, VA 22161 TABLE OF CONTENTS 1. DIII-D PROGRAM OVERVIEW 1-1 1.1. Introduction 1-1 1.2. Highlights of the FY92 DIII-D Research Program 1-5 1.2.1. Divertor Radiation 1-5 1.2.2. Improved Understanding of VH-Mode 1-6 1.2.3. Fast Wave Current Drive 1-6 1.2.4. Toroidal Alfven Eigenmodes 1-9 2. DIVERTOR AND BOUNDARY RESEARCH PROGRAM. 2-1 2.1. Overview 2-1 2.2. Divertor Physics 2-2 2.2.1. Divertor and SOL Scaling Studies 2-2 2.2.2. Scrape-off Layer Measurements 2-6 2.2.3. Radiative Divertor 2-7 2.2.4. Heat Flux Profile Structures and Toroidal Asymmetries 2-8 2.2.5. Lithium Beam Edge Diagnostic 2-10 2.3. Modeling and Edge Database 2-10 2.3.1. SOL Modeling 2-10 2.3.2. Edge Database , 2-12 2.4. Impurity Transport and Control 2-14 3. ADVANCED TOKAMAK STUDIES 3-1 3.1. Overview 3-1 3.2. H-Mode Confinement 3-2 3.3. Improved Confinement through Modification of the Current Profile 3-8 3.4. VH-Mode 3-11 3.5. Noninductive Current Drive 3-21 3.5.1. Electron Cyclotron Heating for Fast Wave Current Drive 3-21 3.5.2. Fast Wave Heating and Current Drive 3-21 3.5.3. Fast Wave Current Drive 3-22 4. TOKAMAK PHYSICS 4-1 4.1. Overview 4-1 4.2. Toroidal Alfven Eigenmodes and Other Global Alfven Modes 4-1 4.3. Magnetic Braking for Study of the Sole of Rotation on Turbulence and Confinement 4-13 in 4.4. Dimensionless Variable Scaling Experiments 4-14 4.5. Confinement Scaling with Electron Cyclotron Heating 4-17 4.6. Theory of Plasma Particle and Heat Pinches 4-18 4.7. Experimental Studies of the Heat Pinch 4-21 4.7.1. Introduction 4-21 4.7.2. Off-Axis ECH Experiments 4-21 4.7.3. Off-Axis NBI Heating Experiments 4-23 4.8. Fast Wave Electron Heating Without the Faraday Shield 4-27 5. OPERATIONS 5-1 5.1. Tokamak Operations 5-1 5.1.1. Operations Summary 5-1 5.1.2. In-Vessel Work 5-1 5.1.3. Vessel Conditioning 5-5 5.2. Neutral Beam Operations : 5-6 5.2.1. Operations Summary 5-6 5.2.2. System Improvement and Maintenance 5-6 5.2.3. System Availability 5-8 5.3. Electron Cyclotron and Ion Cyclotron Heating Operations 5-10 5.3.1. Electron Cyclotron Heating Operations 5-10 5.3.2. Fast Wave Heating and Current Drive Operations 5-10 5.4. Disruption Studies and Plasma Control 5-11 5.4.1. Introduction 5-11 5.4.2. Plasma Control 5-16 5.5. Diagnostics 5-20 5.5.1. Overview 5-20 5.5.2. New or Upgraded Diagnostics 5-20 5.5.3. Diagnostics Under Development 5-27 5.6. Reliability and Availability 5-28 5.6.1. Integrated Preventive Maintenance Program 5-28 5.6.2. Significant Event Review 5-29 5.7. Radiation Management 5-30 5.8. Electrical Engineering 5-32 5.8.1. Overview 5-32 5.8.2. Operation Support 5-32 5.8.3. Coil Power Systems 5-33 5.8.4. High Voltage Systems 5-33 5.8.5. AC Systems 5-33 5.8.6. Instrumentation and Control Systems 5-34 5.8.7. Preventive Maintenance 5-34 5.9. Mechanical Engineering 5-34 5.9.1. Tokamak Systems 5-34 5.9.2. Fluid Systems 5-38 5.10. FY92 Computer Data Systems 5-40 5.10.1. DIII-D 5-40 5.10.2. Computer Hardware Upgrades 5-40 5.10.3. Software Improvements 5-41 IV 5.10.4. Remote Access for Off-Site Collaboration 5-42 5.10.5. Computer Replacement Plan 5-42 5.10.6. Preventive Maintenance Tracking Program Improved 5-43 5.10.7. New CAD System Better Supports DIII-D 5-44 5.10.8. Plan for Computer Connection to Russia 5-44 6. PROGRAM DEVELOPMENT 6-1 6.1. Overview 6-1 6.2. Advanced Divertor Program 6-2 6.2.1. Overview 6-2 6.2.2. Thermal Analysis of the Divertor Cryopump 6-4 6.3. 110 GHz ECH System 6-6 7. SUPPORT SERVICES 7-1 7.1. Quality Assurance 7-1 7.1.1. Design Support 7-1 7.1.2. Inspection Support 7-1 7.1.3. As-Built Measurement Support 7-2 7.1.4. Optical Tooling/Layout/Alignment Support 7-3 7.1.5. QA System Improvements 7-3 7.1.6. Other Support 7-4 7.2. Planning and Control 7-4 7.3. Environment Safety and Health 7-4 7.3.1. Overview 7-4 7.3.2. FY92 Safety 7-6 7.3.3. Radiation Safety 7-10 7.3.4. FY92 Radiation Safety 7-11 7.4. Visitor and Public Information Program 7-14 8. CONTRIBUTION TO ITER PHYSICS R&D 8-1 9. TPX SUPPORT 9-1 9.1. Programmatic Activities 9-1 9.2. Physics and Machine Operations 9-1 9.3. Divertor Studies 9-2 9.4. Component Engineering 9-3 10. COLLABORATIVE EFFORTS 10-1 10.1. DIII-D Collaboration Programs Overview 10-1 10.1.1. Japan Atomic Energy Research Institute 10-1 10.1.2. National Laboratories 10-2 10.1.3. University Programs 10-9 10.2. International Cooperation 10-10 10.2.1. JET 10-11 V 10.2.2. ASDEX-U 10-11 10.2.3. Tore Supra 10-11 10.2.4. JT-60U 10-13 10.2.5. TEXTOR 10-14 10.2.6. COMPASS-D 10-15 10.2.7. TSP 10-15 10.2.8. T-10 ECH Collaboration 10-15 11. FY92 PUBLICATIONS 11-1 LIST OF FIGURES 1.1-1. Cross section of DIII-D with flux surfaces of a double-null divertor discharge superimposed 1-2 1.2-1. Peaked heat flux is fairly independent of both D2 injection rate and injection location, when plotted versus neutral pressure in the midplane and divertor 1-6 1.2-2. Variation of energy confinement time enhancement factor with average triangularity of the separatrix flux surface for single- and double-null discharges 1-7 1.2-3. Current drive efficiency y for the same discharges as in Fig. 3.5-3 as a function of central electron temperature 1-8 1.2-4. TAE frequency dependence on vA, observed and calculated frequencies at increasing toroidal magnetic field 1-9 2.2-1. Scaling of the peak heat flux to the divertor for ELMing H-mode plasmas ... 2-4 2.2-2. Electron temperature and electron density of the outer strike point versus input power 2-5 2.2-3. Density profiles in the SOL for L-, H-, and VH-modes, measured by the SNLA/UCLA probe 2-6 2.2-4. Particle transport in the SOL as measured by the SNLA/UCLA probe 2-8 2.2-5. Peak heat flux to the divertor is reduced as the midplane pressure increases.. 2-9 2.2-6. Evolution of the DIII-D divertor target plate heat flux profile during a double-null VH-mode 2-11 2.3-1. Radial profile for (a) electron density, and (b) electron and ion temperature 2-13 VI 2.3-2. Scaling relationships are extracted from the boundary database BNDY 2-14 2.4-1. Parameters during a shot which attains VH-mode; interferometric measured ne, Da, spectroscopic signals, Tg, and the injected and radiated power 2-16 2.4-2. Contour plot of scrape-off Te and ne as a function of effective radial localities r/a = p and time, along with the results of the 2D penetration model for carbon, oxygen and nickel, showing the fraction of launched neutral C, O, Ni particles that make it past the separatrix 2-17 2.4-3. The energy confinement time, normalized to JET/DIII-D scaling versus input power 2-18 2.4-4.