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1. Development of Resonant Diplexers for high-power ECRH – Status, Applications, Plans

Author

Kasparek W., Plaum B., Lechte C., Wu Z., Wang H., Maraschek M., Stober J., Wagner D., Reich M., Schubert M., Grünwald G., Monaco F., Müller S., Schütz H., Erckmann V., Doelman N., van den Braber R., Klop W., van den Brand H., Bongers W., Krijger B., Petelin M., Koposova E., Lubyako L., Bruschi A., and Sakamoto K.

Subjects
Physics, QC1-999
Abstract

The development of diplexers for ECRH has been pursued at a number of institutes because of their attractive variety of applications: Power combination, non-mechanical, electrically controlled switching (of combined beams) between launchers with tens of kHz, and discrimination of low-power ECE signals from high-power ECRH is feasible. In a first part, this paper reports on plasma experiments with a ring resonator (Mk IIa) at ASDEX Upgrade. Commissioning experiments on fast switching between two launchers for synchronous stabilization of neoclassical tearing modes, as well as in-line ECE measurements have been performed, and experimental issues and first results are discussed. A clear influence of the switching phase on the amplitude of the 3/2 NTM mode was measured, complete stabilization could, however, not be demonstrated yet mainly due to imperfect resonator control. Concepts for improved tracking of the diplexers to the gyrotron frequency are presented. In a second part, the design of diplexers with ring resonators matched to HE11 fields is briefly discussed; these devices can be connected to corrugated waveguides without any mode converters. A compact version (MQ IV) is under investigation, which is compatible with the ITER ECRH system (170 GHz, 63.5 mm waveguide, vacuum tight casing), with the final goal of high-power tests at the 170 GHz gyrotron facility at JAEA in Naka, Japan. First low-power test results are presented.

Published
2015
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2. Commissioning of inline ECE system within waveguide based ECRH transmission systems on ASDEX upgrade

Author

Donné A.J.H., Amerongen F.J., de Baar M.R., Meo F., van den Brand H., van den Braber R., Doelman N., Kasparek W., Bongers W.A., Elzendoorn B.S.Q., Erckmann V., Goede A.P.H., Giannone L., Grünwald G., Hollman F., Kaas G., Krijger B., Michel G., Lubyako L., Monaco F., Noke F., Petelin M., Plaum B., Purps F., ten Pierik J.G.W, Schüller C., Slob J.W., Stober J.K., Schütz H., Wagner D., Westerhof E., and Ronden D.M.S.

Subjects
Physics, QC1-999
Abstract

A CW capable inline electron cyclotron emission (ECE) separation system for feedback control, featuring oversized corrugated waveguides, is commissioned on ASDEX upgrade (AUG). The system is based on a combination of a polarization independent, non-resonant, Mach-Zehnder diplexer equipped with dielectric plate beam splitters [2, 3] employed as corrugated oversized waveguide filter, and a resonant Fast Directional Switch, FADIS [4, 5, 6, 7] as ECE/ECCD separation system. This paper presents an overview of the system, the low power characterisation tests and first high power commissioning on AUG.

Published
2012
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3. Status of Resonant Diplexer Development for high-power ECRH Applications

Author

Bongers W., Fritz E., Doelman N., van den Braber R., Wagner D., Stober J., Schütz H., Schubert M, Purps F., Noke F., Müller S., Monaco F., Michel G., Maraschek M., Hollmann F., Grünwald G., Erckmann V., Filipovic E., Lechte C., Plaum B., Kasparek W., Krijger B., Petelin M., Lubyako L., Bruschi A., and Sakamoto K.

Subjects
Physics, QC1-999
Abstract

Characteristics of ring resonator diplexers for high-power ECRH are briefly reviewed. Commissioning experiments performed on ASDEX Upgrade with the diplexer Mk IIa are presented, which demonstrate slow and fast switching of the power between two launchers, and thus the capability for efficient suppression of neoclassical tearing modes and simultaneous central heating of the plasma. The development of the compact diplexer Mk IIIb is discussed, and test results are presented. Finally, an evacuated design for 170 GHz is shown.

Published
2012
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4. Controlled Mirror Motion System for Resonant Diplexers in ECRH Applications

Author

Monaco F., Maraschek M., de Baar M., Purps F., Noke F., Michel G., Hollmann F., Klop W., Dekker B., Fritz E., Stober J., Krijger B., Bongers W., Erckmann V., Kasparek W., van den Braber R., Doelman N., Müller S., Schütz H., and Wagner D.

Subjects
Physics, QC1-999
Abstract

High-power resonant diplexers for millimetre waves have various promising applications in ECRH systems. The round-trip resonator length of a diplexer needs to be accurately tuned to match its prescribed functionality. For this purpose one of the mirrors in the FADIS MkIIa diplexer has been mounted on a motion system, in order to control the mirror to its desired location despite the presence of substantial disturbances. The mechanical properties and control strategy for the mirror motion system have been designed such as to meet the overall system requirements. The performance of the motion system has been experimentally validated in various high power mm-wave tests.

Published
2012
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8. Controlled Mirror Motion System for Resonant Diplexers in ECRH Applications

Author

Doelman, N.J., Van den Braber, R., Kasparek, W., Erckmann, V., Bongers, W.A., Krijger, B., Stober, J., Fritz, E., Dekker, B., Klop, W., Hollmann, F., Michel, G., Noke, F., Purps, F., de Baar, M.R., Maraschek, M., Monaco, F., Müller, S., Schütz, H., Wagner, D., Team, ASDEXUpgrade, and institutes, otherteams at the contributing

Subjects
Engineering, OM - Opto-Mechatronics, TS - Technical Sciences, Industrial Innovation, business.industry, Physics, QC1-999, Mechatronics, Mechanics & Materials, Power (physics), System requirements, Resonator, Electronic engineering, Millimeter, Electronics, business, Diplexer, Motion system
Abstract

High-power resonant diplexers for millimetre waves have various promising applications in ECRH systems. The round-trip resonator length of a diplexer needs to be accurately tuned to match its prescribed functionality. For this purpose one of the mirrors in the FADIS MkIIa diplexer has been mounted on a motion system, in order to control the mirror to its desired location despite the presence of substantial disturbances. The mechanical properties and control strategy for the mirror motion system have been designed such as to meet the overall system requirements. The performance of the motion system has been experimentally validated in various high power mm-wave tests. © Owned by the authors, published by EDP Sciences, 2012.

Published
2012

10. Commissioning of inline ECE system within waveguide based ECRH transmission systems on ASDEX upgrade

Author

Bongers, W. A., Kasparek, W., Doelman, N., van den Braber, R., van den Brand, H., Meo, Fernando, de Baar, M. R., Amerongen, F. J., Donne, A. J. H., Elzendoorn, B. S. Q., Erckmann, V., Goede, A. P. H., Giannone, L., Grünwald, G., Hollman, F., Kaas, G., Krijger, B., Michel, G., Lubyako, L., Monaco, F., Noke, F., Petelin, M., Plaum, B., Purps, F., ten Pierik, J. G. W., Schüller, C., Slob, J. W., Stober, J. K., Schütz, H., Wagner, D., Westerhof, E., and Ronden, D. M. S.

Abstract

A CW capable inline electron cyclotron emission (ECE) separation system for feedback control, featuring oversized corrugated waveguides, is commissioned on ASDEX upgrade (AUG). The system is based on a combination of a polarization independent, non-resonant, Mach-Zehnder diplexer equipped with dielectric plate beam splitters [2, 3] employed as corrugated oversized waveguide filter, and a resonant Fast Directional Switch, FADIS [4, 5, 6, 7] as ECE/ECCD separation system. This paper presents an overview of the system, the low power characterisation tests and first high power commissioning on AUG.

Published
2012

11. Commissioning of inline ECE system within waveguide based ECRH transmission systems on ASDEX upgrade

Author

Bongers, W.A., Kasparek, W., Doelman, N.J., Van den Braber, R., van den Brand, H., Meo, F., de Baar, M.R., Amerongen, F.J., Donne, A.J. H., Elzendoorn, B.S. Q., Erckmann, V., Goede, A.P. H., Giannone, L., Grünwald, G., Hollmann, F., Kaas, G., Krijger, B., Michel, G., Lubyako, L., Monaco, F., Noke, F., Petelin, M., Plaum, B., Purps, F., Pierik, J.G. W. ten, Schuller, C., Slob, J.W., Stober, J.K., Schütz, H., Wagner, D., Westerhof, E., Ronden, D.M. S., institutes, teamsat the contributing, and Team, ASDEXUpgrade

Subjects
Engineering, Waveguide filter, OM - Opto-Mechatronics, TS - Technical Sciences, Industrial Innovation, business.industry, Physics, QC1-999, Cyclotron, Electrical engineering, Transmission system, Mechatronics, Mechanics & Materials, law.invention, Optics, ASDEX Upgrade, law, Electronics, business, Diplexer, Waveguide, Beam splitter
Abstract

A CW capable inline electron cyclotron emission (ECE) separation system for feedback control, featuring oversized corrugated waveguides, is commissioned on ASDEX upgrade (AUG). The system is based on a combination of a polarization independent, non-resonant, Mach-Zehnder diplexer equipped with dielectric plate beam splitters [2, 3] employed as corrugated oversized waveguide filter, and a resonant Fast Directional Switch, FADIS [4, 5, 6, 7] as ECE/ECCD separation system. This paper presents an overview of the system, the low power characterisation tests and first high power commissioning on AUG. © Owned by the authors, published by EDP Sciences, 2012.

Published
2012

12. Status of Resonant Diplexer Development for high-power ECRH Applications

Author

Kasparek, W., Plaum, B., Lechte, C., Filipovic, E., Erckmann, V., Grünwald, G., Hollmann, F., Maraschek, M., Michel, G., Monaco, F., Müller, S., Noke, F., Purps, F., Schubert, M., Schütz, H., Stober, J., Wagner, D., Van den Braber, R., Doelman, N.J., Fritz, E., Bongers, W.A., Krijger, B., Petelin, M., Lubyako, L., Bruschi, A., Sakamoto, K., Team, ASDEXUpgrade, and institutes, otherteams at the contributing

Subjects
Engineering, TS - Technical Sciences, Industrial Innovation, business.industry, Physics, QC1-999, NI - Nano Instrumentation, Electrical engineering, Plasma, Fast switching, Power (physics), Resonator, ASDEX Upgrade, Physics & Electronics, Sustainable Chemical Industry, ____, Optoelectronics, Nanotechnology, Diplexer, business
Abstract

Characteristics of ring resonator diplexers for high-power ECRH are briefly reviewed. Commissioning experiments performed on ASDEX Upgrade with the diplexer Mk IIa are presented, which demonstrate slow and fast switching of the power between two launchers, and thus the capability for efficient suppression of neoclassical tearing modes and simultaneous central heating of the plasma. The development of the compact diplexer Mk IIIb is discussed, and test results are presented. Finally, an evacuated design for 170 GHz is shown. © Owned by the authors, published by EDP Sciences, 2012.

Published
2012

13. Controlled High-Power Microwave Diplexers

Author

Kasparek W., van den Braber R., Doelman N., Fritz E., Erckmann V., Hollmann F., Michel G., Noke F., Purps F., Bongers W., Krijger B., Eminoglou E., Petelin M., Lubyako L., Bruschi A., Stober J., Wagner D., Plaum B., Filipovic E., Saliba M., and teams at the contributing institutes

Subjects
____
Abstract

___

Published
2011

14. High-Power Performance of a Resonant Diplexer for Advanced ECRH

Author

Kasparek, W [ 1 ], Van den Braber, R [ 2 ], Doelman, N [ 2 ], Fritz, E [ 2 ], Erckmann, V [ 3 ], Hollmann, F [ 3 ], Michel, G [ 3 ], Noke, F [ 3 ], Purps, F [ 3 ], Bongers, W [ 4 ], Krijger, B [ 4 ], Petelin, M [ 5 ], Lubyako, L [ 5 ], Bruschi, A [ 6 ], ECRH Groups at IPP Greifswald, and IPF Stuttgart

Subjects
high-power diplexers, electron cyclotron heating, Physics::Plasma Physics, power combination
Abstract

Electron cyclotron resonance heating (ECRH) systems for next-step large fusion devices operate in continuous wave power in the multimegawatt range. The unique feature of narrow and well-localized power deposition assigns a key role to ECRH for different tasks, such as plasma start-up, electron heating, current drive, magnetohydrodynamic (MHD) control and profile shaping. The integration of high-power microwave diplexers in the transmission lines will improve the flexibility and efficiency while simultaneously reducing the complexity of large ECRH systems. They can serve as power or beam combiners, as slow and fast directional switches to toggle the power from continuously operating gyrotrons between two launchers, and as discriminators of low-power electron cyclotron emission (ECE) signals from high-power ECRH using a common transmission line and antenna. Among various design options a resonant diplexer with a narrow resonance was selected for application at ASDEX Upgrade. The design is driven by the specific physics requirements for MHD control experiments and possible use for line-of-sight ECE. The compact, waveguide-compatible design features a feedback-controlled mirror drive for tracking of the resonator to the gyrotron frequency. High-power, long-pulse tests were performed with the 140-GHz ECRH system for the stellarator W7-X. Results on the transmission characteristics, power combination, and stationary and controlled distribution of the input power to two outputs are presented. The qualification for in-line ECE was investigated.

Published
2011

16. Intermediate frequency band digitized high dynamic range radiometer system for plasma diagnostics and real-time Tokamak control

Author

Bongers, W.A., Beveren, van, V., Thoen, D.J., Nuij, P.W.J.M., Baar, de, M.R., Donné, A.J.H., Westerhof, E., Goede, A.P.H., Krijger, B., Berg, van den, M.A., Kantor, M., Graswinckel, M.F., Hennen, B.A., Schüller, F.C., Bongers, W.A., Beveren, van, V., Thoen, D.J., Nuij, P.W.J.M., Baar, de, M.R., Donné, A.J.H., Westerhof, E., Goede, A.P.H., Krijger, B., Berg, van den, M.A., Kantor, M., Graswinckel, M.F., Hennen, B.A., and Schüller, F.C.

Abstract

An intermediate frequency (IF) band digitizing radiometer system in the 100–200 GHz frequency range has been developed for Tokamak diagnostics and control, and other fields of research which require a high flexibility in frequency resolution combined with a large bandwidth and the retrieval of the full wave information of the mm-wave signals under investigation. The system is based on directly digitizing the IF band after down conversion. The enabling technology consists of a fast multi-giga sample analog to digital converter that has recently become available. Field programmable gate arrays (FPGA) are implemented to accomplish versatile real-time data analysis. A prototype system has been developed and tested and its performance has been compared with conventional electron cyclotron emission (ECE) spectrometer systems. On the TEXTOR Tokamak a proof of principle shows that ECE, together with high power injected and scattered radiation, becomes amenable to measurement by this device. In particular, its capability to measure the phase of coherent signals in the spectrum offers important advantages in diagnostics and control. One case developed in detail employs the FPGA in real-time fast Fourier transform (FFT) and additional signal processing. The major benefit of such a FFT-based system is the real-time trade-off that can be made between frequency and time resolution. For ECE diagnostics this corresponds to a flexible spatial resolution in the plasma, with potential application in smart sensing of plasma instabilities such as the neoclassical tearing mode (NTM) and sawtooth instabilities. The flexible resolution would allow for the measurement of the full mode content of plasma instabilities contained within the system bandwidth.

Published
2011

17. Intermediate frequency band digitized high dynamic range radiometer system for plasma diagnostics and real-time Tokamak control

Author

Bongers, WA. (author), Van Beveren, V. (author), Thoen, D.J. (author), Nuij, P.J.W.M. (author), De Baar, M.R. (author), Donné, A.J.H. (author), Westerhof, E. (author), Goede, A.P.H. (author), Krijger, B. (author), Van den Berg, M.A. (author), Kantor, M. (author), Graswinckel, M.F. (author), Hennen, B.A. (author), Schüller, F.C. (author), Bongers, WA. (author), Van Beveren, V. (author), Thoen, D.J. (author), Nuij, P.J.W.M. (author), De Baar, M.R. (author), Donné, A.J.H. (author), Westerhof, E. (author), Goede, A.P.H. (author), Krijger, B. (author), Van den Berg, M.A. (author), Kantor, M. (author), Graswinckel, M.F. (author), Hennen, B.A. (author), and Schüller, F.C. (author)

Abstract

An intermediate frequency (IF) band digitizing radiometer system in the 100–200 GHz frequency range has been developed for Tokamak diagnostics and control, and other fields of research which require a high flexibility in frequency resolution combined with a large bandwidth and the retrieval of the full wave information of the mm-wave signals under investigation. The system is based on directly digitizing the IF band after down conversion. The enabling technology consists of a fast multi-giga sample analog to digital converter that has recently become available. Field programmable gate arrays (FPGA) are implemented to accomplish versatile real-time data analysis. A prototype system has been developed and tested and its performance has been compared with conventional electron cyclotron emission (ECE) spectrometer systems. On the TEXTOR Tokamak a proof of principle shows that ECE, together with high power injected and scattered radiation, becomes amenable to measurement by this device. In particular, its capability to measure the phase of coherent signals in the spectrum offers important advantages in diagnostics and control. One case developed in detail employs the FPGA in real-time fast Fourier transform (FFT) and additional signal processing. The major benefit of such a FFT-based system is the real-time trade-off that can be made between frequency and time resolution. For ECE diagnostics this corresponds to a flexible spatial resolution in the plasma, with potential application in smart sensing of plasma instabilities such as the neoclassical tearing mode (NTM) and sawtooth instabilities. The flexible resolution would allow for the measurement of the full mode content of plasma instabilities contained within the system bandwidth., QN/Quantum Nanoscience, Applied Sciences

Published
2011
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18. Intermediate frequency band digitized high dynamic range radiometer system for plasma diagnostics and real-time Tokamak control

Author

Bongers, W. A., primary, van Beveren, V., additional, Thoen, D. J., additional, Nuij, P. J. W. M., additional, de Baar, M. R., additional, Donné, A. J. H., additional, Westerhof, E., additional, Goede, A. P. H., additional, Krijger, B., additional, van den Berg, M. A., additional, Kantor, M., additional, Graswinckel, M. F., additional, Hennen, B. A., additional, and Schüller, F. C., additional

Published
2011
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19. High-Power Performance of a Resonant Diplexer for Advanced ECRH

Author

Kasparek, W., Van Den Braber, R., Doelman, N., Fritz, E., Erckmann, V., Hollmann, F., Michel, G., Noke, F., Purps, F., Bongers, W., Krijger, B., Petelin, M., Lubyako, L., and Bruschi, A.

Abstract

AbstractElectron cyclotron resonance heating (ECRH) systems for next-step large fusion devices operate in continuous wave power in the multimegawatt range. The unique feature of narrow and well-localized power deposition assigns a key role to ECRH for different tasks, such as plasma start-up, electron heating, current drive, magnetohydrodynamic (MHD) control and profile shaping. The integration of high-power microwave diplexers in the transmission lines will improve the flexibility and efficiency while simultaneously reducing the complexity of large ECRH systems. They can serve as power or beam combiners, as slow and fast directional switches to toggle the power from continuously operating gyrotrons between two launchers, and as discriminators of low-power electron cyclotron emission (ECE) signals from high-power ECRH using a common transmission line and antenna. Among various design options a resonant diplexer with a narrow resonance was selected for application at ASDEX Upgrade. The design is driven by the specific physics requirements for MHD control experiments and possible use for line-of-sight ECE. The compact, waveguide-compatible design features a feedback-controlled mirror drive for tracking of the resonator to the gyrotron frequency. High-power, long-pulse tests were performed with the 140-GHz ECRH system for the stellarator W7-X. Results on the transmission characteristics, power combination, and stationary and controlled distribution of the input power to two outputs are presented. The qualification for in-line ECE was investigated.

Published
2011
Full Text
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