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Recent few years a multi-frequency gyrotron for modernization of ASDEX Upgrade ECRH system is under development in GYCOM/IAP by contract with IPP. Following contract specifications the gyrotron must produce 10-s pulses with 1MW output... more
Recent few years a multi-frequency gyrotron for modernization of ASDEX Upgrade ECRH system is under development in GYCOM/IAP by contract with IPP. Following contract specifications the gyrotron must produce 10-s pulses with 1MW output power at 140GHz and over 800-kW power at 3 additional frequencies within 105-140GHz frequency range. The gyrotron output window is to be transparent for radiation in
Gyrotron is used as a source of microwaves in electron-cyclotron-wave systems of fusion installations. Application of EC waves for plasma heating (ECH) and current drive (ECCD) in magnetic fusion devices. The demand of a new generation of... more
Gyrotron is used as a source of microwaves in electron-cyclotron-wave systems of fusion installations. Application of EC waves for plasma heating (ECH) and current drive (ECCD) in magnetic fusion devices. The demand of a new generation of fusion devices is the development of one megawatt gyrotrons for CW operation in the frequency band (80÷170) GHz. This paper considers the state of the art of such gyrotrons with enhanced performance for fusion concentrating on critical issues of their elaboration. The prospects for future steps in development of multi-megawatt gyrotron with frequency tunability are also studied.
Page 1. Objectives, physics requirements and conceptual design of an ECRH system for JET This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2011 Nucl. Fusion 51 063033... more
Page 1. Objectives, physics requirements and conceptual design of an ECRH system for JET This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2011 Nucl. Fusion 51 063033 (http://iopscience.iop.org/0029-5515/51/6/063033) ...
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ABSTRACT Recent test results of newly designed 1.5-1.7 MW/170 GHz gyrotron which is considered as a possible RF source for the ITER program are presented.
... Trans. Plasma Science, Vol. 32, pp. 67-72, 2004. [2] Bykov Yu., Denisov G., Eremeev A. et al., 28 GHz 10 kW gyrotron system for electron cyclotron resonance ion source, Rev. Sci. Instruments, Vol.75, pp. 1437-1439, 2004. ...
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ABSTRACT High power microwave radiation is applied for an ever increasing range of programs aimed to create materials with new qualities. The gyrotron complexes for microwave material processing created at IAP RAS jointly with GYCOM Ltd.... more
ABSTRACT High power microwave radiation is applied for an ever increasing range of programs aimed to create materials with new qualities. The gyrotron complexes for microwave material processing created at IAP RAS jointly with GYCOM Ltd. do not have any analogues with similar functional capabilities but they are less effective than decimeter wavelength systems. The complexes use gyrotrons at the second cyclotron harmonic with the efficiency output of 30-40% as a source of microwave radiation. The expansion of gyrodevice based systems to novel technology and industrial applications requires further efficiency increase. The electron beam energy recovery is one of the most effective methods to achieve this. The presented results have been used for development of high efficiency harmonic gyrotron with depressed collector.
ABSTRACT Design and results of experimental tests of a high-power sub-terahertz gyrotron with a pulse solenoid for remote detection of radioactive materials are presented. Operating frequency corresponds to the atmospheric transparency... more
ABSTRACT Design and results of experimental tests of a high-power sub-terahertz gyrotron with a pulse solenoid for remote detection of radioactive materials are presented. Operating frequency corresponds to the atmospheric transparency window (0.66-0.67 THz). The 200 kW output power in pulses up to 30 microsecond duration were obtained.
The ITER EC system is in the process of being revised as a result of the ITER design review that occurred during 2007. This revision is introducing several modifications to the gyrotron and transmission line layout as well as identify... more
The ITER EC system is in the process of being revised as a result of the ITER design review that occurred during 2007. This revision is introducing several modifications to the gyrotron and transmission line layout as well as identify several interface issues between the subsystems comprising the EC system. Each modification aims at improving the EC systems performance while
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... Bykov, G. Denisov, A. Eremeev, G. Kalynova, V. Kholoptsev, E. Kopelovich, A. Kufiin, V. Lygin, A. Pavelyev, I. Plotnikov, V. Zapwalov, N ... ripple; a cathode filament power supply with the feedback loop applied to it to stabilize the... more
... Bykov, G. Denisov, A. Eremeev, G. Kalynova, V. Kholoptsev, E. Kopelovich, A. Kufiin, V. Lygin, A. Pavelyev, I. Plotnikov, V. Zapwalov, N ... ripple; a cathode filament power supply with the feedback loop applied to it to stabilize the gyrotron electron beam current; an ion pump power ...
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Main components of the prototype 10 kW CW 30 GHz gyrotron system for millimeter-wave processing of materials have been considerably improved. Modifications have been introduced into the design of the gyrotron, transmission line, microwave... more
Main components of the prototype 10 kW CW 30 GHz gyrotron system for millimeter-wave processing of materials have been considerably improved. Modifications have been introduced into the design of the gyrotron, transmission line, microwave furnace, and temperature diagnostics and control subsystems. This has made it possible to increase the millimeter-wave power feeding the furnace by more than 1.5 times, significantly
ABSTRACT The ITER ECH&CD system will have an installed power of 24 MW at 170 GHz delivered to the launchers at the plasma side through a transmission line sub-system constituted by evacuated HE11 waveguides, DC breaks, power... more
ABSTRACT The ITER ECH&CD system will have an installed power of 24 MW at 170 GHz delivered to the launchers at the plasma side through a transmission line sub-system constituted by evacuated HE11 waveguides, DC breaks, power monitors, mitre bends, polarizers, switches, loads and pumping sections. Each line will be typically about 160 m in length and will connect the RF power sources alternatively to the equatorial launcher or to one of the upper launchers in order to accomplish the various physics requirements: heating, current drive and instability control. Two different source configurations are at the moment under study, pending the final decision about the European 2 MW coaxial gyrotron development. Each configuration will imply a dedicated transmission line layout. An overview of the actual design is presented and the technical requirements are discussed.
A 26 MW Electron Cyclotron Heating and Current Drive (EC H&CD) system is to be installed for ITER. The main objectives are to provide, start-up assist, central H&CD and control of MHD activity. These are achieved by a combination... more
A 26 MW Electron Cyclotron Heating and Current Drive (EC H&CD) system is to be installed for ITER. The main objectives are to provide, start-up assist, central H&CD and control of MHD activity. These are achieved by a combination of two types of launchers, one located in an equatorial port and the second type in four upper ports. The physics applications are partitioned between the two launchers, based on the deposition location and driven current profiles. The equatorial launcher (EL) will access from the plasma axis to mid radius with a relatively broad profile useful for central heating and current drive applications, while the upper launchers (ULs) will access roughly the outer half of the plasma radius with a very narrow peaked profile for the control of the Neoclassical Tearing Modes (NTM) and sawtooth oscillations. The EC power can be switched between launchers on a time scale as needed by the immediate physics requirements. A revision of all injection angles of all launchers is under consideration for increased EC physics capabilities while relaxing the engineering constraints of both the EL and ULs. A series of design reviews are being planned with the five parties (EU, IN, JA, RF, US) procuring the EC system, the EC community and ITER Organization (IO). The review meetings qualify the design and provide an environment for enhancing performances while reducing costs, simplifying interfaces, predicting technology upgrades and commercial availability. In parallel, the test programs for critical components are being supported by IO and performed by the Domestic Agencies (DAs) for minimizing risks. The wide participation of the DAs provides a broad representation from the EC community, with the aim of collecting all expertise in guiding the EC system optimization. Still a strong relationship between IO and the DA is essential for optimizing the design of the EC system and for the installation and commissioning of all ex-vessel components when several teams from several DAs will be involved together in the tests on the ITER site.
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This paper reviews the design and functionality of the 24 MW 170 GHz electron cyclotron heating and current drive system being planned for the ITER Tokamak. The sub-systems (power supplies, gyrotrons, transmission lines and launcher... more
This paper reviews the design and functionality of the 24 MW 170 GHz electron cyclotron heating and current drive system being planned for the ITER Tokamak. The sub-systems (power supplies, gyrotrons, transmission lines and launcher antennas) are described based on present day technologies, while on-going R&D provides component and sub-system testing with the possibility of increasing the reliability of the
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The 28 GHz gyrotron system (GS) has been purposely designed to meet present-day demand for a microwave source for powering an electron cyclotron resonance ion source capable of producing both high total current and high average ion... more
The 28 GHz gyrotron system (GS) has been purposely designed to meet present-day demand for a microwave source for powering an electron cyclotron resonance ion source capable of producing both high total current and high average ion charge. A gyrotron oscillator of GS operates ...
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First bandwidth measurements of a novel gyrotron amplifier are presented. The coupling between the second harmonic cyclotron mode of a gyrating electron beam and the radiation field occurred in the region of near infinite phase velocity... more
First bandwidth measurements of a novel gyrotron amplifier are presented. The coupling between the second harmonic cyclotron mode of a gyrating electron beam and the radiation field occurred in the region of near infinite phase velocity over a broad bandwidth by using a cylindrical waveguide with a helical corrugation on its internal surface. With a beam energy of 185 keV, the amplifier achieved a maximum output power of 1.1 MW, saturated gain of 37 dB, linear gain of 47 dB, saturated bandwidth of 8.4 to 10.4 GHz ( 21% relative bandwidth), and an efficiency of 29%, in good agreement with theory.
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Electron cyclotron current drive will become the main scheme on ITER for the stabilization of neoclassical tearing modes (NTMs) and the control of sawtooth oscillations. The effectiveness of this scheme forms the basis for the... more
Electron cyclotron current drive will become the main scheme on ITER for the stabilization of neoclassical tearing modes (NTMs) and the control of sawtooth oscillations. The effectiveness of this scheme forms the basis for the requirements of the ITER Upper Port Launcher. These requirements include the need for steering the mm-wave beam to the pertinent magnetic flux surfaces where the
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A new ECRH system is being constructed for ASDEX Upgrade with a total power of 4 MW, generated by four gyrotrons, and a pulse duration of 10 s. Particular features are the use of gyrotrons which can work at various frequencies in the... more
A new ECRH system is being constructed for ASDEX Upgrade with a total power of 4 MW, generated by four gyrotrons, and a pulse duration of 10 s. Particular features are the use of gyrotrons which can work at various frequencies in the range 104–140 GHz and correspondingly broad band transmission components. The transmission will be at normal air pressure,
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ABSTRACT ITER will use Electron Cyclotron Current Drive (ECCD) for stabilization of neoclassical tearing modes (NTM) and sawteeth control. This determines the steering range required for the ITER Upper Port Launcher (UPL). Two concepts... more
ABSTRACT ITER will use Electron Cyclotron Current Drive (ECCD) for stabilization of neoclassical tearing modes (NTM) and sawteeth control. This determines the steering range required for the ITER Upper Port Launcher (UPL). Two concepts for the UPL have been put forward: Front Steering (FS, reference design) and Remote Steering (RS, fall-back option). The main drawback of the RS concept is that the output steering range is inversely coupled to the focusing of the front mirror system. This puts a constraint on the NTM stabilisation efficiency that can be achieved for a given steering range. By using wider and longer Square Corrugated Waveguides (SCWs), this effect can be ameliorated. In this paper, the status of two variants of the RS concept with different SCW size is discussed. Although the NTM stabilisation performance of long (SCW of 8 m) RS Launcher is improved over the short (SCW of 4 m), a comparison of the two variants on all critical design issues motivated to progress the short design. Potential improvements to the short design such as the application of non spherical mirror curvatures, tapered SCWs, curved SCWs and the use of general astigmatic beams are investigated. By applying a bent SCW, the front mirrors can be omitted completely in the current port plug design, enhancing plasma accessibility. This approach has been modelled and is shown not to satisfy the ITER requirements due to its lower transmission efficiency. The RS option with non spherical front mirrors gives an improvement of about 5%, additional application of a tapered SCW adds 3%. A "tightened limited range" short SCW RS launcher gives an improvement of 25 % with a reduced heat load of 4.7 MW/m 2 , within the ITER requirements. An alternative RS launcher concept is introduced, in which the SCWs have been omitted.
The Free-Electron Maser (FEM) is a high power, wideband, tunable mm-wave source in the range of 130-260 GHz for fusion applications. Without electron beam recovery, the fusion-FEM has generated over 700 kW at 200 GHz in the microsecond... more
The Free-Electron Maser (FEM) is a high power, wideband, tunable mm-wave source in the range of 130-260 GHz for fusion applications. Without electron beam recovery, the fusion-FEM has generated over 700 kW at 200 GHz in the microsecond scale. Single-mode operation has been demonstrated at various frequencies. A fusion FEM has been completed for long-pulse operation; the energy recovery system, a decelerator and a depressed collector have been installed. in this paper we present results on measurements of the complete mm-wave beam line for long-pulse operation
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ABSTRACT Since the end of EDA, the design of the Electron Cyclotron Heating and Current Drive (ECH&CD) system has been modified to respond to progress in physics understanding and change of interface conditions. Nominal RF power... more
ABSTRACT Since the end of EDA, the design of the Electron Cyclotron Heating and Current Drive (ECH&CD) system has been modified to respond to progress in physics understanding and change of interface conditions. Nominal RF power of 20 MW is shared by four upper launchers or one equatorial launcher RF beams are steered by front steering mirrors providing wide sweeping angle for the RF beam. DC high voltage power supply may be composed of IGBT pulse step modulators because of high frequency modulation and design flexibility to three different types of 170 GHz gyrotrons provided by three parties. The RF power from the 170 GHz gyrotron is transmitted to the launcher by 63.5 mmϕ corrugated waveguide line and remotely switched by a waveguide switch between the upper launcher and the equatorial launcher. The ECH&CD system has also a start‐up sub‐system for assist of initial discharge composed of three 127.5 GHz gyrotrons and a dedicated DC high voltage power supply. Three of transmission lines are shared between 170 GHz gyrotron and 127.5 GHz gyrotron so as to inject RF beam for the start‐up through the equatorial launcher. R&Ds of components for high power long pulse and mirror steering mechanism have been on‐going in the parties to establish a reliable ITER ECH&CD system.