Gyrotron Oscillators for High Output Power
Author | : Christopher J. Edgcombe |
Publisher | : |
Total Pages | : 22 |
Release | : 1978 |
Genre | : Gyrotrons |
ISBN | : |
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Author | : Christopher J. Edgcombe |
Publisher | : |
Total Pages | : 22 |
Release | : 1978 |
Genre | : Gyrotrons |
ISBN | : |
Author | : C Edgecombe |
Publisher | : CRC Press |
Total Pages | : 447 |
Release | : 1993-11-15 |
Genre | : Technology & Engineering |
ISBN | : 1482272369 |
The performance of gyrotrons has developed rapidly during recent years and they now form very powerful sources of microwave energy at millimetric wavelengths. Much development, both of the detailed theory including multi-mode interaction and of practical devices, has taken place in the major European laboratories. This book is a collection of surve
Author | : Machavaram V. Kartikeyan |
Publisher | : Springer Science & Business Media |
Total Pages | : 234 |
Release | : 2013-03-14 |
Genre | : Technology & Engineering |
ISBN | : 3662076373 |
Drawing on the author's wide experience, this book gives a comprehensive review of the state of the art in gyrotron technology, covering the theory, design and applications. The book includes an extensive references list which provides an excellent guide to the related literature.
Author | : Thumm, Manfred |
Publisher | : KIT Scientific Publishing |
Total Pages | : 158 |
Release | : 2021-10-28 |
Genre | : Technology & Engineering |
ISBN | : |
This report presents an update of the experimental achievements published in the review “State- of-the-Art of High-Power Gyro-Devices and Free Electron Masers”, Journal of Infrared, Millime-ter, and Terahertz Waves, 41, No. 1, pp 1-140 (2020) related to the development of gyro-devices (Tables 2-34). Emphasis is on high-power gyrotron oscillators for long-pulse or continuous wave (CW) operation and pulsed gyrotrons for any applications.
Author | : David Samuel Tax |
Publisher | : |
Total Pages | : 205 |
Release | : 2013 |
Genre | : |
ISBN | : |
The gyrotron is a source capable of producing megawatt power levels at millimeter-wave frequencies for many important applications, including electron cyclotron heating and current drive in magnetic fusion devices. It is important that the gyrotron operates with high efficiency and provides a high quality output beam to minimize system size, maximize reliability and avoid additional losses in external systems. This thesis presents the experimental study of such a gyrotron designed to operate at MW power levels and whose initial 110 GHz operation was expanded to include operation at 124.5 GHz. To this end, a new set of components, including a cavity, mode converter, and output window were designed for operation at both frequencies. The cavity was designed using the code MAGY and the Q factors of 830 for the TE22,6,1mode at 110 GHz and 1060 for the TE24,7,1 mode at 124.5 GHz would be suitable for CW operation in an industrial gyrotron. The mode converter consisting of a dimpled-wall launcher and 4 phasecorrecting mirrors could theoretically produce an output beam with 99 % Gaussian beam content at each frequency while a single-disc window was implemented with over 99.5 % power transmission at both frequencies. The achieved output power in experiment was 1.1 MW at 110 GHz and 850 kW at 124.5 GHz for the design parameters of 96 kV and 40 A. At 98 kV and 42 A, the gyrotron achieved 1.25 MW and 1 MW at 110 and 124.5 GHz, respectively. Mode competition is typically a major limitation in such gyrotrons, and stable single-mode operation was demonstrated at both frequencies. At 110 GHz, the output beam had 98.8 % Gaussian beam content, while at 124.5 GHz, the output beam quality was 94.4 %. Another experiment within this thesis demonstrated the implementation of a mode converter with smooth mirrors that would be less susceptible to machining and misalignment errors. A Gaussian beam content of 96 % was measured in that experiment. In addition, a thorough study of the gyrotron start-up scenario was performed, for which experimental work had been lacking in the literature. The start-up scenario is the sequence of modes that are excited during the rise of the voltage pulse and is essential for the gyrotron to operate in its most efficient regime known as the hard self-excitation regime. This gyrotron operates nominally in the TE22,6,1 mode near the 110 GHz cutoff frequency with an axial field profile that is approximately Gaussian at the steady-state peak voltage. In experiments performed in the smooth mirror mode converter configuration, lower frequency modes were observed at lower voltages as opposed to higher frequency modes as predicted by theory. Analysis of these modes showed that they are backward-wave modes far from their cutoff frequency which have higher order axial field profiles, i.e. TE21,6,3 and TE21,6,4 modes at frequencies of 108-109 GHz. The excitation of these modes was investigated and shown to be possible by using theory and single-mode simulations with the code MAGY. This discovery was important as these modes were not included in past code runs, and thus future improvements can be made to incorporate this effect.
Author | : Thumm, Manfred |
Publisher | : KIT Scientific Publishing |
Total Pages | : 164 |
Release | : 2024-02-06 |
Genre | : |
ISBN | : |
This report presents an update of the experimental achievements published in the review “State- of-the-Art of High-Power Gyro-Devices and Free Electron Masers”, Journal of Infrared, Millimeter, and Terahertz Waves, 41, No. 1, pp 1-140 (2020) and in the KIT Scientific Report 7761 (2021), related to the development of gyro-devices (Tables 2-34). Emphasis is on high-power gyrotron oscillators for long-pulse or continuous wave (CW) operation and pulsed gyrotrons for any applications.
Author | : |
Publisher | : |
Total Pages | : |
Release | : 1986 |
Genre | : |
ISBN | : |
Varian has designed and tested 140 GHz gyrotron oscillators that have generated output powers of 100 kW CW and 200 kW for 1 ms pulses. Upcoming tubes will be designed to operate at power levels of 200 kW CW and ultimately up to 1 MW CW. The important design considerations which are addressed in the higher power tubes include the design of the electron gun, interaction circuit, and output window. These issues will be discussed and the results of the earlier 140 GHz gyrotron work at Varian will be summarized.
Author | : Udaybir Singh |
Publisher | : Springer Nature |
Total Pages | : 146 |
Release | : 2022-08-22 |
Genre | : Science |
ISBN | : 9811946108 |
This book highlights the emission, transmission, and launching of an electron beam. It presents an overview and recent advances in order to enhance knowledge in the field of gyrotron in general and electron gun in particular. The book is presented in seven chapters starting with the introduction and ending with future possible directions in the field of electron beams and gyrotrons.
Author | : Antonio Carlos Torrezan de Sousa |
Publisher | : |
Total Pages | : 185 |
Release | : 2010 |
Genre | : |
ISBN | : |
This thesis reports the design and experimental demonstration of frequency-tunable submillimeter-wave gyrotrons operating in continuous wave (CW) at the second harmonic of the electron cyclotron frequency. An unprecedented continuous frequency tuning range of more than 1 GHz has been achieved in both a 330- and a 460-GHz gyrotron via magnetic field tuning or voltage tuning. The 330-GHz gyrotron has generated 19 W of power in a cylindrical TE4,3,q mode from a 13-kV 190-mA electron beam. The minimum start current was measured to be 21 mA, where good agreement was verified between the measured start current values and the calculation from linear theory for the first six axial modes, q = 1 through 6. A continuous tuning range of 1.2 GHz with a minimum output power of 1 W has been achieved experimentally via magnetic or beam voltage tuning. The output stability of the gyrotron running under a computerized control system was assessed to be ±0.4% in power and ±3 ppm in frequency during a 110-hour uninterrupted CW test. Evaluation of the gyrotron microwave output beam using a pyroelectric camera indicated a Gaussian-like mode content of 91%. Measurements were also carried out in microsecond pulse operation at a higher beam current (610 mA), yielding a minimum output power of 20 W over a tuning range of 1.2 GHz obtained by means of cyclotron frequency tuning and thermal tuning. The 330-GHz gyrotron will be used as a source for 500 MHz nuclear magnetic resonance (NMR) experiments with sensitivity enhanced by dynamic nuclear polarization (DNP). In addition to the 330-GHz gyrotron, the design and CW operation of a tunable second-harmonic 460-GHz gyrotron are described. The 460-GHz gyrotron operates in the whispering gallery mode TE1 1,2 and has generated 16 W of output power with a 13-kV 100-mA electron beam. The start oscillation current measured over a range of magnetic field values is in good agreement with theoretical start currents obtained from linear theory for successive high order axial modes TE1,2,q. The minimum start current is 27 mA. Power and frequency tuning measurements as a function of the electron cyclotron frequency have also been carried out. A smooth frequency tuning range of 1 GHz with a minimum output power of 2 W has been obtained for the operating second-harmonic mode either by magnetic field tuning or beam voltage tuning. Long-term CW operation was evaluated during an uninterrupted period of 48 hours, where the gyrotron output power and frequency were kept stable to within ±0.7% and ±6 ppm, respectively, by a computerized control system. Proper operation of an internal quasi-optical mode converter implemented to transform the operating whispering gallery mode to a Gaussian-like beam was also verified. Based on images of the gyrotron output beam taken with a pyroelectric camera, the Gaussian-like mode content of the output beam was computed to be 92% with an ellipticity of 12%. The 460-GHz gyrotron is intended to be used as a submillimeter-wave source in a 700-MHz DNP/NMR spectrometer.
Author | : Chao-Hai Du |
Publisher | : Springer |
Total Pages | : 200 |
Release | : 2014-05-29 |
Genre | : Technology & Engineering |
ISBN | : 3642547281 |
A gyrotron traveling-wave amplifier (gyro-TWT) with the high-power and broad-band capabilities is considered as a turn-on key for next generation high-resolution radar. The book presents the most advanced theory, methods and physics in a gyro-TWT. The most challenging problem of instability competition has been for the first time addressed in a focused and systematic way and reported via concise states and vivid pictures. The book is likely to meet the interest of researchers and engineers in radar and microwave technology, who would like to study the gyro-TWTs and to promote its application in millimeter-wave radars. Chao-Hai Du and Pu-Kun Liu are both professors at Peking University.