Introduction to the Physics of Gyrotrons

by Nusinovich, Gregory S.; Granatstein, Victor; Temkin, Richard

• ISBN13: 9780801879210
• ISBN10: 0801879213
• eBook ISBN(s): 9781421429410
• Format: Hardcover
• Copyright: 2004-06-30
• Publisher: Johns Hopkins Univ Pr

Summary

As unique sources of coherent high-power, microwave, and millimeter-wave radiation, gyrotrons are an essential part of the hunt for controlled fusion. Presently, gyrotrons are actively used for electron cyclotron resonance plasma heating and current drive in various controlled fusion reactors. These sources have been under development in many countries for more than forty years. In spite of their widespread use, however, there is as yet no single book to introduce non-specialists to this vital field. Now Gregory S. Nusinovich, an early pioneer of the gyrotron and widely regarded today as the world's leading authority on the subject, explains the fundamental physical principles upon which gyrotrons and related devices operate. Nusinovich first sets forth some "rules of thumb" that allow readers to understand gyrotron operation in simple terms. He then explores the fundamentals of the general theory of gyrotrons and offers an overview of the various types of gyro-devices, including gyromonotrons, gyroklystrons, gyro-traveling-wave tubes, and gyrotwystrons. He explains not only the theory, linear and nonlinear, but also the practical challenges that users of such devices face. This book will be of interest to undergraduate and graduate students as well as to those who develop gyrotrons or who use them in various applications. It should also appeal to plasma physicists interested in charged-particle dynamics, as well as to applied physicists needing to know more about micro- and millimeter-wave technologies.

Author Biography

Gregory S. Nusinovich is a senior research scientist at the Institute for Research in Electronics and Applied Physics at the University of Maryland and Fellow of The American Physical Society and The Institute of Electrical and Electronics Engineers.

Table of Contents

Foreword, by Victor Granatstein and Richard Temkin	xi
Preface	xiii
PART I INTRODUCTION TO GYRODEVICES
Chapter 1 Introduction	3	(18)
1.1. Relativistic Dependence of Electron Cyclotron Frequency on Electron Energy	3	(5)
1.2. Quantum Interpretation of Induced Cyclotron Radiation	8	(2)
1.3. Autoresonance	10	(3)
1.4. Normal and Anomalous Doppler Effects	13	(2)
1.5. Electron Deceleration	15	(2)
1.6. Optimum Choice of Parameters	17	(2)
1.7. Problems and Solutions	19	(2)
Chapter 2 Gyrotron Arrangement	21	(26)
2.1. Velocity Spread and Inhomogeneous Doppler Broadening Operation Near Cutoff	21	(4)
2.2. Electron Optics. Magnetron Injection Guns	25	(5)
2.3. Microwave Structures (Cavities and Waveguides)	30	(6)
2.4. Types of Gyrodevices	36	(1)
2.5. Magnets and Solenoids	37	(5)
2.6. Problems and Solutions	42	(5)
PART II THEORY OF GYROTRON OSCILLATORS AND AMPLIFIERS
Chapter 3 Linear Theory of the Gyromonotron	47	(25)
3.1. Transversely Homogeneous Model	47	(4)
3.2. Gyro-Averaged Equations of Electron Motion: General Approach	51	(6)
3.3. Excitation of Resonators: General Form	57	(6)
3.4. Self-Excitation Conditions	63	(3)
3.5. Mode Selection	66	(2)
3.6. Problems and Solutions	68	(4)
Chapter 4 Nonlinear Theory of the Gyromonotron (Single-Mode Treatment)	72	(20)
4.1. Cold-Cavity Approximation	72	(4)
4.2. Self-Consistent Approach	76	(5)
4.3. Effect of Velocity Spread	81	(3)
4.4. Space-Charge Effects	84	(3)
4.5. Trade-Offs in the Gyrotron Design	87	(2)
4.6. Problems and Solutions	89	(3)
Chapter 5 Mode Interaction in the Gyromonotron	92	(27)
5.1. Preliminary Remarks	92	(1)
5.2. Main Effects in the Mode Interaction	92	(11)
5.3. Start-up Scenario	103	(7)
5.4. Phase Locking in Multimode Gyrotrons	110	(6)
5.5. Problems and Solutions	116	(3)
Chapter 6 Linear Theory of the Gyro-TWT	119	(24)
6.1. Introduction: Instability in Magnetoactive Plasma	119	(5)
6.2. Derivation of the Dispersion Equation for the Gyro-TWT	124	(8)
6.3. Small-Signal Gain in Single-Stage and Multistage Devices	132	(3)
6.4. Bandwidth	135	(3)
6.5. Stability	138	(5)
Chapter 7 Nonlinear Theory of the Gyro-TWT	143	(24)
7.1. Self-Consistent Set of Equations. Energy Conservation Law. Low-Current Limit	143	(6)
7.2. Beam-Wave Interaction	149	(7)
7.3. Gain and Bandwidth	156	(4)
7.4. Concluding Remarks	160	(1)
7.5. Problems and Solutions	160	(7)
Chapter 8 Theory of Gyroklystrons	167	(22)
8.1. Introductory Remarks	167	(1)
8.2. General Formalism. Point-Gap Model	168	(4)
8.3. Gain, Bandwidth, and Efficiency	172	(4)
8.4. Two-Cavity Gyroklystron	176	(7)
8.5. Problems and Solutions	183	(6)
Chapter 9 Fluctuations: Intrinsic and Extrinsic Noise	189	(26)
9.1. Radiation Linewidth, Sources of Noise	189	(2)
9.2. General Formalism	191	(8)
9.3. Intrinsic Noise Sources. Shot Noise	199	(5)
9.4. Extrinsic Noise	204	(1)
9.5. Phase Stability of Gyroamplifiers	205	(4)
9.6. Problems and Solutions	209	(6)
PART III THE DEVELOPMENT OF GYRODEVICES
Chapter 10 Gyrotron Oscillators for Controlled Fusion Experiments	215	(24)
10.1. Historical Introduction	215	(5)
10.2. Quasi-Optical Mode Converters	220	(7)
10.3. Output Windows	227	(3)
10.4. Depressed Collectors	230	(2)
10.5. Experimental Results	232	(7)
Chapter 11 Gyroklystrons	239	(10)
11.1. Historical Introduction	239	(2)
11.2. Gyroklystrons for Radar Applications	241	(4)
11.3. Gyroklystrons for Charged Particle Accelerators	245	(4)
Chapter 12 Gyro-Traveling-Wave Tubes	249	(8)
12.1. Historical Introduction	249	(1)
12.2. Large-Bandwidth Gyro-TWTs	250	(5)
12.3. High-Gain Gyro-TWTs	255	(2)
Chapter 13 Other Types of Gyrodevices	257	(29)
13.1. Gyro-Backward-Wave Oscillator	257	(8)
13.2. Gyrotwystron	265	(3)
13.3. Quasi-Optical Gyrotron	268	(2)
13.4. Cyclotron Auto-Resonance Maser (CARM)	270	(3)
13.5. Cyclotron Maser Based on the Anomalous Doppler Effect	273	(1)
13.6. Large-Orbit Gyrotron	274	(3)
13.7. Peniotron, Gyropeniotron, and Autoresonant Peniotron	277	(7)
13.8. Problems and Solutions	284	(2)
Summary	286	(3)
Appendix 1: Derivation of Gyro-Averaged Equations	289	(6)
Appendix 2: Wave Excitation by Electron Beams in Waveguides	295	(5)
Appendix 3: Derivation of the Self-Consistent Set of Equations for the Gyro-TWT	300	(9)
References	309	(20)
Index	329