Stellarator physics : proceedings of the seventh International Workshop on Stellarators

COVER......Page 1
FOREWORD......Page 5
EDITORIAL NOTE......Page 6
CONTENTS......Page 7
2. MAIN STELLARATOR EXPERIMENTS......Page 13
3.1. Magnetic configuration studies......Page 17
3.2. Plasma currents......Page 18
3.3. Particle and impurity control, divertors......Page 19
5. MHD EQUILIBRIUM AND STABILITY......Page 20
7. NEXT-GENERATION EXPERIMENTS......Page 22
ACKNOWLEDGEMENTS......Page 24
OVERVIEW OF EXPERIMENTAL RESULTS......Page 25
STATUS OF THE ADVANCED STELLARATOR WENDELSTEIN W 7AS: FIRST RESULTS AND FURTHER PROGRAMME......Page 26
1. CHARACTERISTICS OF WENDELSTEIN W 7AS......Page 27
2. START OF THE W 7AS EXPERIMENT......Page 28
3. FIRST RESULTS OF WENDELSTEIN W 7AS......Page 29
REFERENCES......Page 31
OVERVIEW OF THE ATF PROGRAM......Page 33
I. INTRODUCTION......Page 34
II. SUMMARY OF INITIAL ATF OPERATION......Page 36
REFERENCES......Page 43
I. Introduction......Page 45
II. Configuration control experiments......Page 46
III. Divertor Plasma Measurements......Page 48
REFERENCES......Page 49
1. Introduction......Page 50
3. ECH Experiment......Page 51
4. ICRF Plasma Production......Page 53
REFERENCES......Page 54
Introduction......Page 55
History and Results......Page 56
TRANSPORT......Page 60
Introduction......Page 61
Results for a model plasma......Page 62
Parameters of a selected discharge......Page 63
Results from experiment and simulations......Page 64
Conclusions......Page 67
REFERENCES......Page 68
1. Introduction......Page 69
3 Toroidal Symmetry in ECH Plasmas......Page 70
4. Poloidal Symmetry in ECH Plasmas......Page 71
5. Impurity Influx in RF Produced Plasmas......Page 73
REFERENCES......Page 74
ECH PLASMA......Page 75
NEUTRAL-BEAM-HEATED PLASMA......Page 76
REFERENCES......Page 78
CONVECTIVE TRANSPORT IN IMS......Page 79
Mode Structure Measurements......Page 83
Dependence on magnetic field strength and collision rate......Page 86
Comparison with linear dispersion theory......Page 87
OPTIMIZATION OF TRANSPORT IN STELLARATORS......Page 89
REFERENCES......Page 92
THE ROLE OF THE RADIAL ELECTRIC FIELD IN ENHANCED CONFINEMENT REGIMES IN STELLARATORS*......Page 93
REFERENCES......Page 96
1. Introduction......Page 97
2. The temperature gradient in the scrape-off layer......Page 98
4. Conclusions......Page 99
IMPURITIES AND DIVERTORS......Page 100
DIVERTOR BIASING EXPERIMENTS IN IMS......Page 101
REFERENCES......Page 104
Measured "Footprint" Data......Page 105
Possible mechanisms for observad flows and present and future Investigations......Page 107
References......Page 110
I. Plasma Model......Page 111
II. Results......Page 112
2. Experimental Arrangement......Page 115
4. Results......Page 117
References......Page 119
1. INTRODUCTION......Page 120
2. VACUUM VESSEL AND PUMPING SYSTEM......Page 121
3. BAKING AND GDC SYSTEMS......Page 123
4. CLEANING AND CONDITIONING OF THE INTERNAL COMPONENTS......Page 124
7. SUMMARY......Page 127
REFERENCES......Page 129
DIAGNOSTICS......Page 130
Physical Basis......Page 131
Conceptual Design for a CO2 Laser Based Diagnostic......Page 132
Discussion......Page 137
I Introduction......Page 138
III Numerical Simulation of |B| Measurement......Page 140
IV Numerical Simulation of the Poloidal Field Measurement......Page 142
Acknowledgments......Page 144
References......Page 145
FIR Interferometer System......Page 146
References......Page 149
INTRODUCTION......Page 150
PHASE II RESULTS (MAY-SEPTEMBER 1988)......Page 152
EARLY PHASE III RESULTS (FEBRUARY-MARCH 1989)......Page 155
REFERENCES......Page 156
1. INTRODUCTION......Page 157
2. MICROWAVE INTERFERENCE FROM ECH POWER......Page 158
3. PLASMA RADIATIVE POWER MEASUREMENTS......Page 160
REFERENCES......Page 161
TVCD's......Page 162
TOMOGRAPHIC RECONSTRUCTION......Page 165
REFERENCES......Page 166
2. THE INTERFEROMETER......Page 167
3. TOMOGRAPHIC CAPABILITY......Page 169
REFERENCES......Page 171
2. Experimental Setup......Page 172
3. Intensity of the Doppler-shifted HQ......Page 173
4. Attenuation Profile of the Injected Neutral Beam......Page 174
References......Page 175
INTRODUCTION......Page 176
TWO DIMENSIONAL MODEL......Page 178
SCHEME FOR ECH ON STELLARATORS......Page 179
REFERENCES......Page 180
ECH, CONFINEMENT - EXPERIMENTS......Page 181
1. Introduction......Page 182
3. Experimental results......Page 183
References......Page 187
2. Global Confinement......Page 188
3. Hollow Density Profile......Page 190
4. Magnetic Axis Shift......Page 192
REFERENCES......Page 193
2. THE EXPERIMENT......Page 194
3. RESULTS AND DISCUSSION......Page 195
REFERENCES......Page 198
EXPERIMENTAL STUDIES ON THE TOHOKU UNIVERSITY HELIAC......Page 199
I. Magnetic Configuration......Page 200
II. Measurement of Magnetic Configuration Parameters......Page 201
III. Plasma Production by ECRH......Page 202
REFERENCES......Page 204
STABILITY STUDIES......Page 205
SECOND STABILITY STUDIES IN ATF*......Page 206
CONFIGURATIONS UNDER STUDY......Page 208
NUMERICAL METHODS......Page 209
NUMERICAL RESULTS OF THE STABILITY ANALYSIS......Page 211
REFERENCES......Page 212
2 Effects of Toroidal Plasma current on the MHD stability......Page 213
3 Magnetic Axis Shift Experiment......Page 214
REFERENCES......Page 216
RF HEATING......Page 217
Introduction......Page 218
ECH Current Drive......Page 219
Conclusions......Page 222
REFERENCES......Page 223
Introduction......Page 224
ECH Launcher Design......Page 225
Measured Results......Page 226
REFERENCES......Page 227
3. Microwave source......Page 228
4. Results......Page 229
REFERENCES......Page 231
MICROWAVE ABSORPTION IN STELLARATORS (TJ-II) AND TORSATRONS (STORM)......Page 232
TJ-II......Page 233
STORM......Page 234
REFERENCES......Page 236
I. Introduction......Page 237
II. ECH Plasmas......Page 238
III. ICRF Plasma......Page 242
2. ICRF plasma production......Page 245
3. Experimental results......Page 246
REFERENCES......Page 248
4. Numerical modelling......Page 249
References......Page 254
2. MICROWAVE PLASMA PRODUCTION......Page 255
3. LOW FREQUENCY PLASMA PRODUCTION......Page 256
4. CONCLUSIONS......Page 258
REFERENCES......Page 259
ANALYTIC MODEL FOR ECH PROFILES......Page 260
REFERENCES......Page 264
EQUILIBRIUM AND STABILITY......Page 265
METHOD......Page 266
NUMERICAL RESULTS......Page 268
CONCLUSIONS......Page 270
REFERENCES......Page 271
RELATION BETWEEN MERCIER CRITERION AND LOW-n MODE STABILITY......Page 272
References......Page 275
1. Variational Principle......Page 276
2. Numerical Method [2 , 3].......Page 278
3. Some preliminary results......Page 279
REFERENCES......Page 282
FLUCTUATION STUDIES IN ATF......Page 283
ACKNOWLEDGEMENT......Page 287
MODEL.......Page 288
NUMERICAL RESULTS.......Page 289
REFERENCES......Page 291
INTRODUCTION......Page 292
APPLICATION TO W7AS STELLARATOR......Page 293
SYSTEM IMPROVEMENTS......Page 295
REFERENCES......Page 296
INTRODUCTION......Page 297
W7A STELLARATOR DATA ANALYSIS......Page 298
CONCLUSIONS......Page 301
DISSIPATIVE TRAPPED ELECTRON MODES IN I = 2 TORSATRONS......Page 302
REFERENCES......Page 305
EQUILIBRIUM AND IDEAL STABILITY STUDIES FOR ATF......Page 306
ACKNOWLEDGEMENT......Page 308
REFERENCES......Page 309
STABILITY ANALYSIS OF FREE BOUNDARY MODES FOR ATF*......Page 310
Introduction......Page 314
Conclusions......Page 316
Self-stabilization......Page 317
References......Page 318
I. INTRODUCTION......Page 319
III. CONVERSION OF OUTPUT FROM THE STEP CODE INTO INPUT FOR THE PIES CODE......Page 320
V. COMMENTS......Page 321
REFERENCES......Page 322
CONFIGURATION EFFECTS, CONFINEMENT......Page 323
INTRODUCTION......Page 324
CONFIGURATIONS, EFFECTS ON THE CONFINEMENT EFFECT OF ROTATIONAL TRANSFORM......Page 325
EFFECT OF PLASMA CURRENT......Page 326
SUMMARY AND CONCLUSIONS......Page 327
REFERENCES......Page 328
Introduction......Page 329
Local Electron Heat Conductivity......Page 330
References......Page 332
II. Transport improvement by inward axis shift......Page 333
III. MHD activities and well-stabilization......Page 336
IV. Summary and Discussion......Page 337
References......Page 338
INITIAL FLUX SURFACE MAPPING EXPERIMENT......Page 339
INITIAL PLASMA RESULTS IN THE PRESENCE OF FIELD ERRORS......Page 340
PLASMA RESULTS AFTER BUS WORK MODIFICATIONS......Page 341
REFERENCES......Page 342
1. INTRODUCTION......Page 343
3. MAGNETIC FLUX SURFACE MEASUREMENTS......Page 344
4. CONCLUSION......Page 346
REFERENCES......Page 347
NEW DEVICE DESIGNS......Page 348
I. Electron Cyclotron Resonance Heating......Page 349
II. Transport......Page 350
III. Stability......Page 351
IV. Engineering Studies......Page 353
REFERENCES......Page 354
MAGNETIC SURFACES, ISLANDS......Page 355
ELECTRON BEAM MAPPING OF THE ATF VACUUM MAGNETIC SURFACES......Page 356
ACKNOWLEDGEMENTS......Page 358
THEORETICAL BACKGROUND......Page 359
MODELING STUDIES AND BUSWORK MODIFICATIONS......Page 360
REFERENCES......Page 362
2. MAGNETIC SURFACE MAPPING......Page 363
3. RESULTS AND DISCUSSIONS......Page 364
REFERENCES......Page 366
ELECTRON BEAM MEASUREMENTS IN SHEILA USING A SIMPLE METHOD OF IMAGE INTENSIFICATION......Page 367
REFERENCES......Page 370
Magnetic Design of H-l......Page 371
Analysis of Error Fields......Page 372
CONFIGURATIONAL EFFECTS ON PLASMA CONFINEMENT IN SHEILA......Page 375
I. Introduction......Page 378
II. Return map and fixed points......Page 379
III. Single-resonance model......Page 380
References......Page 381
STUDIES OF NEW EXPERIMENTS......Page 382
ENGINEERING ASPECTS OF H-l......Page 383
1. MACHINE DESCRIPTION......Page 388
2. HELIAC EQUILIBRIUM......Page 389
3. HARDCORE 0-PINCH EXPERIMENT......Page 390
4. SIMULATED TORIODICITY STUDIES......Page 391
REFERENCES......Page 393
DESIGN OF THE COMPACT AUBURN TORSATRON*......Page 394
REFERENCES......Page 398
ANALYTICAL FIELD RESULTS FOR STELLARATOR/ TORSATRON CONFIGURATIONS......Page 399
REFERENCES......Page 407
3. Configuration properties.......Page 408
4.Microwave heating.......Page 410
6. Drift particle trajectories.......Page 411
8.Conclusions.......Page 412
I. Introduction......Page 413
II. R.F. Multipole Confinement......Page 414
III. R.F. Multipoles in d.c. Magnetic Fields......Page 415
REFERENCES......Page 416
ULTRA-SIMPLE STELLARATORS......Page 417
REFERENCES......Page 423
LARGE NEXT-GENERATION EXPERIMENTS......Page 424
RECENT STATUS OF THE LARGE HELICAL DEVICE PROJECT......Page 425
RECENT DESIGN CONSIDERATIONS FOR THE LARGE HELICAL DEVICE......Page 428
THEORETICAL STUDY OF THE LARGE HELICAL DEVICE......Page 432
Transport Prediction......Page 434
REFERENCES......Page 435
I. Introduction......Page 436
II. Basic Data of Wendelstein VII-X......Page 437
III. Physics Studies......Page 439
REFERENCES......Page 441
2. Results for a Particular Example......Page 442
3. Conclusion......Page 448
LOW-ASPECT-RATIO OPTIMIZATION STUDIES FOR ATF-II*......Page 449
REFERENCES......Page 455
NEXT-GENERATION DEVICES AND REACTORS......Page 456
DIVERTOR DESIGN STUDY OF THE LARGE HELICAL DEVICE......Page 457
COIL SYSTEM AND VACUUM FIELD, 'STANDARD CASE'......Page 461
ADJUSTMENT OF ROTATIONAL TRANSFORM AND AXIS POSITION......Page 468
SUMMARY AND CONCLUSIONS......Page 471
REFERENCES......Page 474
I. METHOD......Page 475
III. SUMMARY......Page 477
REFERENCES......Page 478
EDGE STRUCTURE OF VACUUM FIELDS......Page 479
INTERSECTION WITH FIRST WALL AND/OR LIMITER......Page 482
SUMMARY AND CONCLUSIONS......Page 484
REFERENCES......Page 487
INTRODUCTION......Page 488
HELICAL -RIPPLE TRANSPORT......Page 489
MODULAR-RIPPLE TRANSPORT......Page 490
REFERENCES......Page 491
NUMERICAL METHODS FOR STELLARATOR OPTIMIZATION*......Page 492
REFERENCES......Page 497
INTRODUCTION:......Page 498
RESULTS:......Page 499
REFERENCES......Page 502
INTRODUCTION......Page 503
CABLE-IN-CONDUIT CONDUCTOR CONFIGURATION......Page 504
CONCLUSION......Page 507
REFERENCES......Page 508
ALPHA-PARTICLE LOSSES IN COMPACT TORSATRON REACTORS*......Page 509
ALPHA-PARTICLE LOSSES FOR REFERENCE REACTORS......Page 510
DEPENDENCE ON THE MAGNETIC FIELD STRUCTURE......Page 512
REDUCTION OF DIRECT LOSS FRACTION......Page 513
EFFECTS OF FINITE BETA......Page 515
REFERENCES......Page 517
TRANSPORT SURVEY CALCULATIONS USING THE SPECTRAL COLLOCATION METHOD*......Page 519
THE TRANSPORT EQUATIONS......Page 520
THE CHEBYSHEV COLLOCATION METHOD......Page 521
CONVERGENCE STUDIES......Page 522
NUMERICAL EXAMPLES......Page 523
REFERENCES......Page 526
IMPURITIES, DIVERTORS......Page 528
OPTICAL MEASUREMENTS OF ECRH HELIUM PLASMA IN THE L-2 STELLARATOR......Page 529
REFERENCES......Page 532
2. DIAGNOSTICS......Page 533
4. RESULTS......Page 534
SUMMARY......Page 537
REFERENCES......Page 538
2. PLASMA AND IMPURITY MODELING......Page 539
3. ASYMMETRIES IN PLASMA EMISSIONS AND RADIATED POWER......Page 541
REFERENCES......Page 542
Edge plasma behavior......Page 543
Divertor plasma simulation......Page 545
References......Page 547
2. The role of light and heavy impurities in radiative losses.......Page 548
3. Metal impurity release from surfaces.......Page 550
4. Injected carbon behaviour in a plasma core.......Page 552
REFERENCES......Page 553
BOOTSTRAP CURRENTS......Page 554
Fundamental Equations......Page 555
Qualitative Solution......Page 557
1. INTRODUCTION......Page 559
2. ANALYTIC EXPRESSION FOR BOOTSTRAP CURRENTS......Page 560
3. BOOTSTRAP CURRENT CONTROL IN STELLARATORS......Page 561
4. NUMERICAL COMPARISON WITH DKES RESULTS......Page 565
5. DISCUSSION AND CONCLUSION......Page 566
REFERENCES......Page 568
A Analytic theory......Page 569
C Non-symmetric stellarators......Page 570
E Summary and conclusions.......Page 571
REFERENCES......Page 573
2. THEORY......Page 574
3. EXPERIMENT......Page 576
4. CONCLUSION......Page 578
REFERENCES......Page 579
LIST OF PARTICIPANTS......Page 580