Millimeter-wave imaging diagnostics systems on the EAST tokamak (invited)

Journal Article · Tue Nov 15 00:00:00 EST 2016 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.4959162· OSTI ID:22596495

Zhu, Y. L.; Yu, C. X.; Zhao, Z. L.; Gao, B. X.; Chen, D. X.; Liu, W. D.; Liao, W.; Qu, C. M.; Luo, C. ^[1]; Hu, X.; Spear, A. G.; Luhmann, N. C.; Domier, C. W.; Chen, M.; Ren, X. ^[2]; Tobias, B. J. ^[3]

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1. School of Physics, University of Science and Technology of China, Anhui 230026 (China)
2. University of California, Davis, California 95616 (United States)
3. Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

Millimeter-wave imaging diagnostics, with large poloidal span and wide radial range, have been developed on the EAST tokamak for visualization of 2D electron temperature and density fluctuations. A 384 channel (24 poloidal × 16 radial) Electron Cyclotron Emission Imaging (ECEI) system in F-band (90-140 GHz) was installed on the EAST tokamak in 2012 to provide 2D electron temperature fluctuation images with high spatial and temporal resolution. A co-located Microwave Imaging Reflectometry (MIR) will be installed for imaging of density fluctuations by December 2016. This “4th generation” MIR system has eight independent frequency illumination beams in W-band (75-110 GHz) driven by fast tuning synthesizers and active multipliers. Both of these advanced millimeter-wave imaging diagnostic systems have applied the latest techniques. A novel design philosophy “general optics structure” has been employed for the design of the ECEI and MIR receiver optics with large aperture. The extended radial and poloidal coverage of ECEI on EAST is made possible by innovations in the design of front-end optics. The front-end optical structures of the two imaging diagnostics, ECEI and MIR, have been integrated into a compact system, including the ECEI receiver and MIR transmitter and receiver. Two imaging systems share the same mid-plane port for simultaneous, co-located 2D fluctuation measurements of electron density and temperature. An intelligent remote-control is utilized in the MIR electronics systems to maintain focusing at the desired radial region even with density variations by remotely tuning the probe frequencies in about 200 μs. A similar intelligent technique has also been applied on the ECEI IF system, with remote configuration of the attenuations for each channel.

• OSTI ID: 22596495
• Journal Information: Review of Scientific Instruments, Vol. 87, Issue 11; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
APERTURES
ATTENUATION
CONFIGURATION
CYCLOTRONS
DENSITY
DESIGN
DIAGNOSTIC TECHNIQUES
ELECTRON DENSITY
ELECTRON TEMPERATURE
FLUCTUATIONS
GHZ RANGE 01-100
HT-7U TOKAMAK
ILLUMINANCE
IMAGES
MICROWAVE RADIATION
OPTICS
REMOTE CONTROL
TUNING
TWO-DIMENSIONAL CALCULATIONS