Fusion Plasma Diagnostics with mm-Waves: An Introduction

Filling a gap in the literature, this introduction to the topic covers the physics of the standard microwave diagnostics established on modern fusion experiments, and the necessary technological background from the field of microwave engineering. Written by well–known mm–wave diagnosticians in the field of fusion physics, the textbook includes such major diagnostic techniques as electron cyclotron emission, interferometry, reflectometry, polarimetry, and scattering. INDICE: Preface XIII 1 Fusion Research 1 1.1 Reaction Scheme 1 1.2 Magnetic Plasma Confinement 4 1.2.1 Tokamak 5 1.2.2 Stellarator 6 1.2.3 Physics Issues of Magnetic Confinement 7 1.2.4 Plasma Heating 10 1.3 Plasma Diagnostic 11 1.3.1 Generic Arrangements 12 1.3.2 Microwave Diagnostics 15 References 17 2 Millimeter–Waves in Plasmas 19 2.1 Basic Equations 20 2.2 Plasma Dielectric Tensor, General Properties 23 2.3 Dielectric Tensor from Kinetic Theory 25 2.4 Cold–Plasma Limit 29 2.5 Derivation within Fluid Description 32 2.6 Discussion of Cold–Plasma Dispersion Relations 34 2.6.1 Nonmagnetized Plasma, B0 = 0 34 2.6.2 Magnetized Plasma, Parallel Propagation, kB0 37 2.6.3 Magnetized Plasma, Perpendicular Propagation, k ⊥ B0 39 2.6.4 Slightly Oblique Propagation 41 2.7 Finite–Temperature Correction to Cold–Plasma Dielectric Tensor 42 2.7.1 Finite Larmor Radius Expansion 42 2.7.2 Warm–Plasma Approximation 44 2.7.3 Relativistic Corrections 46 2.8 Inhomogeneous Plasma 48 2.8.1 WKB Approximation 49 2.8.2 Refraction 51 2.8.3 Ray Tracing 53 2.9 Finite–Size Probing Beam 54 2.9.1 Gaussian Beam Description 54 2.10 Radiation Transfer 58 2.10.1 Transparent Plasma 58 2.10.2 Plasma Emitting and Absorbing 60 2.10.3 Multiple Chords, Imaging 61 References 62 3 Active Diagnostics 65 3.1 Interferometry 65 3.1.1 Single–Chord Interferometry 68 3.1.2 Multiple Chords 69 3.2 Polarimetry 70 3.2.1 Faraday Effect 71 3.2.2 Cotton–Mouton Effect 75 3.2.3 Common Generalized Description 77 3.3 Reflectometry 83 3.3.1 Time Delay Measurement 86 3.3.2 Phase Change at Cutoff 89 3.3.3 Profile Reconstruction 92 3.3.4 Localization of Reflecting Layer 93 3.3.5 Relativistic Corrections 95 3.3.6 Influence of Density Fluctuations 95 3.4 Scattering 100 3.4.1 Single–Particle Thomson Scattering 101 3.4.2 Doppler Shift 102 3.4.3 Incoherent Scattering 104 3.4.4 Relativistic Incoherent Scattering Spectrum 106 3.4.5 Role of Density Fluctuations 108 3.4.6 Coherent Scattering 108 3.4.7 Electron and Ion Feature 110 3.4.8 Summarizing Comments 113 References 115 4 Passive Diagnostics 117 4.1 Bremsstrahlung 118 4.2 Electron Cyclotron Emission 122 4.2.1 Electron Motion in a Static B–Field 122 4.2.2 Electric Field and Spectrum, Single Electron 123 4.2.3 Perpendicular Observation, Characteristic Modes 126 4.2.4 Spectrum, Electron Ensemble 128 4.2.5 Absorption Coefficient 130 4.2.6 Emission Profile 132 4.2.7 B0–Field Varying along Sightline 135 4.2.8 Optical Depth of Most Relevant Modes 137 4.2.9 Visibility Depth and Localization 139 4.2.10 Electron Cyclotron Absorption Measurement 142 4.3 Electron Bernstein Wave Emission 143 4.3.1 Electron Bernstein Waves 144 4.3.2 Mode Conversion 146 References 149 5 Guided Waves 151 5.1 Transmission Line Properties 151 5.1.1 Waves on a Lossy Transmission Line 151 5.1.2 Terminated Transmission Line 153 5.1.3 Classification of Transmission Lines 157 5.1.4 Surface Currents 160 5.2 Coaxial Transmission Line 161 5.2.1 Characteristic Properties 162 5.2.2 Losses and Limits of Coaxial Lines 162 5.3 Rectangular Waveguides 163 5.3.1 TE Waves 164 5.3.2 TM Waves 166 5.3.3 Attenuation in Rectangular Waveguides 166 5.3.4 Fundamental TE10 Wave 167 5.4 Circular Waveguides 170 5.4.1 Fields in Circular Waveguides 171 5.4.2 TM Waves 172 5.4.3 TE Waves 173 5.4.4 Loss in Circular Waveguides 175 5.5 Multimode Waveguides 176 5.5.1 Number of Modes Propagating 176 5.5.2 Multimode Propagation 178 5.5.3 TE11 Mode in Overmoded Circular Waveguides 179 5.6 Corrugated Circular Waveguides 182 5.6.1 Fields of Corrugated Circular Waveguides 183 5.6.2 Characteristics of HE11 Hybrid Mode 185 5.7 Gaussian Beams 185 5.7.1 Solution of Approximate Wave Equation 185 5.7.2 Transformation of Gaussian Beams 186 5.7.3 Lenses and Curved Mirrors 191 5.7.4 Truncation of Gaussian Beams 193 5.7.5 Coupling Coefficient for Fundamental Gaussian Beams 194 5.8 Vacuum Windows 196 5.8.1 Single–Disk Window 196 5.8.2 Half–Wave Window 197 5.8.3 Thin Window 198 5.8.4 Antireflection Coating 198 References 199 6 Radiation Generation and Detection 201 6.1 Signal Sources 201 6.1.1 Backward–Wave Oscillator 201 6.1.2 Solid–State Oscillators 203 6.1.2.1 Gunn Oscillator 203 6.1.2.2 IMPATT Oscillator 205 6.1.3 Multiplier Chain 206 6.2 Antennas 208 6.2.1 Basic Definitions 208 6.2.2 Antenna Temperature 211 6.2.3 Pyramidal Horn 212 6.2.4 Conical Horn 214 6.2.5 Excitation of Gaussian Beams 215 6.2.6 Antenna Arrays 217 6.3 Detection 221 6.3.1 Overview and Classification 221 6.3.2 Bolometer 223 6.3.3 Hot Electron Bolometer 225 6.3.4 Noise Equivalent Power, NEP 226 6.3.5 Schottky Diode 227 6.3.6 Schottky Diode Frequency Multiplier 229 6.3.7 Diode Direct Detector 231 6.3.8 Schottky Detector Noise 233 6.4 Heterodyne Detection 236 6.4.1 Square–Law Mixer 237 6.4.2 Diode Mixer 239 6.4.3 Two–Port Mixer 241 6.4.4 Mixer Construction 245 6.5 Thermal Noise 246 6.5.1 Noise Temperature 247 6.5.2 Noise Figure 249 6.5.3 Noise Temperature of Cascaded Systems 250 6.5.4 Mixer Noise Temperature 251 6.5.5 Noise Temperature of Heterodyne Receiver 253 6.5.6 Measurement of Noise Temperature 255 6.6 Sensitivity Limits 256 6.6.1 Shot Noise Term 256 6.6.2 Thermal Radiation Term 258 6.6.3 Influence of Bandwidth 259 6.6.4 Noise–Equivalent Power, Incoherent Detection 260 6.6.5 Noise–Equivalent Power, Coherent Detection 261 6.6.6 Minimum Detectable Temperature 263 6.7 Correlation Radiometry 264 6.7.1 Intensity Fluctuations 264 6.7.2 Cross–Correlation Function 265 6.7.3 Intensity Fluctuations and Coherence 266 6.7.4 van Cittert–Zernike Theorem 268 6.7.5 Intensity Interferometer 269 6.7.6 Accuracy of Cross–Correlation Measurements 270 6.7.7 Alternative Decorrelation 271 References 273 7 Components and Subsystems 275 7.1 Two–Port Characterization 275 7.1.1 Scattering Parameters 275 7.1.2 Transmission and Reflection 278 7.1.3 Directional Coupler 281 7.1.4 Nonreciprocal Devices 283 7.2 Network–Analysis Measuring Techniques 286 7.2.1 Transmission Measurement 286 7.2.2 Reflection Measurement 287 7.2.3 Substitution Measurement 288 7.2.4 Measurements Using Noise Sources 289 7.3 Frequency– and Polarization–Selective Filters 290 7.3.1 General Definitions 291 7.3.2 Waveguide Band–Stop Filter 292 7.3.3 Band–Pass Filter in Overmoded Waveguide 293 7.3.4 Metallic Meshes 296 7.3.5 Polarization Filters 298 7.4 Phase Measurement 299 7.4.1 Phase Measurements with Analog Output 299 7.4.2 All–Digital Phase Measurement 301 7.4.3 Phase Determination by Software 303 7.5 Signal Linearity 304 7.5.1 Gain Compression 304 7.5.2 Intermodulation 305 7.6 Frequency Stability 308 7.6.1 Control Loop Components 308 7.6.2 PLL Circuits in the Millimeter–Wave Range 309 7.6.3 Comments on the Theoretical Concept 310 References 313 8 Architecture of Realized Millimeter–Wave Diagnostic Systems 315 8.1 Interferometer 315 8.1.1 Comments on Wavelength 316 8.1.2 Mach–Zehnder Interferometer 318 8.1.3 Mach–Zehnder Heterodyne Interferometer 319 8.1.4 Frequency Stability 320 8.1.5 Path Length Variations 322 8.1.6 Swept Frequency Interferometer 324 8.1.7 Multichannel Interferometer 324 8.2 Polarimeter 326 8.2.1 Evolution of the Polarization State 326 8.2.2 Modulation Techniques 327 8.2.2.1 Modulation Scheme 1 327 8.2.2.2 Modulation Scheme 2 328 8.2.2.3 Modulation Scheme 3 329 8.2.3 Faraday Polarimeter 329 8.2.4 Cotton–Mouton Polarimeter 330 8.3 Reflectometer 332 8.3.1 Swept Single–Frequency System 333 8.3.2 Multifrequency Systems 337 8.3.3 Pulse Radar Technique 339 8.3.4 Ultrashort Pulse Radar 342 8.3.5 Distance Calibration and Spurious Reflections 344 8.3.6 Comments on Fluctuation Measurements 345 8.3.7 Doppler Reflectometry 346 8.3.8 Imaging Reflectometry 348 8.4 Radiometry of Electron Cyclotron Emission 349 8.4.1 General Requirements 350 8.4.2 Michelson Interferometer 352 8.4.3 Martin–Puplett Polarizing Interferometer 354 8.4.4 Grating Spectrometer 356 8.4.5 Heterodyne Radiometers 357 8.4.6 ECE Imaging 362 8.4.7 System Parameters 363 8.4.8 Calibration 366 8.5 Detection of Electron Bernstein Wave Emission 370 8.6 Coherent Scattering 373 8.7 Summarizing Comments 375 References 378 Appendix A: Symbols and Constants 381 Appendix B: Formulas and Calculations 387 B.1 Functions Qij 387 B.2 Cold–Plasma Limit 388 B.3 FLR Approximation 388 B.4 Warm–Plasma Approximation 390 B.5 Waveguide Attenuation 391 B.6 Metallic Mesh Transmission 393 References 393 Appendix C: Tables and Material Constants 395 C.1 Waveguides, Technical Data 395 C.2 Waveguides, Theoretical Relations 396 C.3 Dielectric Materials, Electrical Data 396 C.4 Dielectric Materials, Mechanical Data 397 C.5 Dielectric Materials, Names 397 C.6 Gunn Oscillators 398 References 398 Index 401

• ISBN: 978-3-527-41105-4
• Editorial: Wiley VCH
• Encuadernacion: Rústica
• Páginas: 424
• Fecha Publicación: 25/09/2013
• Nº Volúmenes: 1
• Idioma: Inglés