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Title: Analog integrator for the Korea superconducting tokamak advanced research magnetic diagnostics

Abstract

An analog integrator, which automatically compensates an integrating drift, has been developed for the magnetic diagnostics in the Korea superconducting tokamak advanced research (KSTAR). The compensation of the drift is done by the analog to digital converter-register-digital to analog converter in the integrator. The integrator will be used in the equilibrium magnetic field measurements by using inductive magnetic sensors during a plasma discharge in the KSTAR machine. Two differential amplifiers are added to the signal path between each magnetic sensor and the integrator in order to improve the performance of the integrator because a long signal cable of 100 m will be used for the measurement in the KSTAR machine. In this work, the characteristics of the integrator with two differential amplifiers are experimentally investigated.

Authors:
; ; ;  [1];  [2]
  1. Research and Development Division, National Fusion Research Center, Daejeon (Korea, Republic of)
  2. (Korea, Republic of)
Publication Date:
OSTI Identifier:
20953417
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 78; Journal Issue: 4; Other Information: DOI: 10.1063/1.2721405; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; AMPLIFIERS; ANALOG-TO-DIGITAL CONVERTERS; CABLES; DIGITAL-TO-ANALOG CONVERTERS; EQUILIBRIUM; INTEGRATED CIRCUITS; MAGNETIC FIELDS; PERFORMANCE; PLASMA; PLASMA CONFINEMENT; REPUBLIC OF KOREA; SENSORS; SIGNALS; TOKAMAK DEVICES

Citation Formats

Bak, J. G., Lee, S. G., Son, D., Ga, E. M., and Department of Physics, Hannam University, Daejeon. Analog integrator for the Korea superconducting tokamak advanced research magnetic diagnostics. United States: N. p., 2007. Web. doi:10.1063/1.2721405.
Bak, J. G., Lee, S. G., Son, D., Ga, E. M., & Department of Physics, Hannam University, Daejeon. Analog integrator for the Korea superconducting tokamak advanced research magnetic diagnostics. United States. doi:10.1063/1.2721405.
Bak, J. G., Lee, S. G., Son, D., Ga, E. M., and Department of Physics, Hannam University, Daejeon. Sun . "Analog integrator for the Korea superconducting tokamak advanced research magnetic diagnostics". United States. doi:10.1063/1.2721405.
@article{osti_20953417,
title = {Analog integrator for the Korea superconducting tokamak advanced research magnetic diagnostics},
author = {Bak, J. G. and Lee, S. G. and Son, D. and Ga, E. M. and Department of Physics, Hannam University, Daejeon},
abstractNote = {An analog integrator, which automatically compensates an integrating drift, has been developed for the magnetic diagnostics in the Korea superconducting tokamak advanced research (KSTAR). The compensation of the drift is done by the analog to digital converter-register-digital to analog converter in the integrator. The integrator will be used in the equilibrium magnetic field measurements by using inductive magnetic sensors during a plasma discharge in the KSTAR machine. Two differential amplifiers are added to the signal path between each magnetic sensor and the integrator in order to improve the performance of the integrator because a long signal cable of 100 m will be used for the measurement in the KSTAR machine. In this work, the characteristics of the integrator with two differential amplifiers are experimentally investigated.},
doi = {10.1063/1.2721405},
journal = {Review of Scientific Instruments},
number = 4,
volume = 78,
place = {United States},
year = {Sun Apr 15 00:00:00 EDT 2007},
month = {Sun Apr 15 00:00:00 EDT 2007}
}
  • Many magnetic diagnostics were fabricated and some of them were calibrated and installed in the Korea Superconducting Tokamak Advanced Research device. Fabrication details and results from the calibrations and installation activities are presented.
  • Magnetic diagnostics for the first plasma operation in the Korea Superconducting Tokamak Advanced Research device are described. The main discussion is the feasibility studies from the magnetic flux and field measurements utilizing the superconducting poloidal field coils before the first plasma generation.
  • Plasma characteristics in the far scrape-off layer region of tokamak play a crucial role in the stable plasma operation and its sustainability. Due to the huge facility, electrical diagnostic systems to measure plasma properties have extremely long cable length resulting in large stray current. To overcome this problem, a sideband harmonic method was applied to the Korea Superconducting Tokamak Advanced Research tokamak plasma. The sideband method allows the measurement of the electron temperature and the plasma density without the effect of the stray current. The measured plasma densities are compared with those from the interferometer, and the results show reliabilitymore » of the method.« less
  • The core and edge Thomson systems on Korea Superconducting Tokamak Advanced Research employ two different sets of lens collection optics. Their collection systems are positioned in the front end of a long reentrant cassette for optimum viewing coverage and optical throughput. Both systems collect the scattered light from a single tangential beam of multiple 50-Hz Nd:YAG lasers and image the scattering volume from core to edge with 40 spatial points. In order to obtain a higher resolution of 5 mm, the edge system has more spatial channels than the core system. Pressure-free heat shield windows, which will absorb the radiationmore » heat flux, are mounted in front of large vacuum windows to protect them from the radiation heat load during long-pulse discharges.« less
  • Frequency modulation reflectometer has been developed to measure the plasma density profile of the Korea Superconducting Tokamak Advanced Research tokamak. Three reflectometers are operating in extraordinary polarization mode in the frequency range of Q band (33.6–54 GHz), V band (48–72 GHz), and W band (72–108 GHz) to measure the density up to 7 × 10{sup 19} m{sup −3} when the toroidal magnetic field is 2 T on axis. The antenna is installed inside of the vacuum vessel. A new vacuum window is developed by using 50 μm thick mica film and 0.1 mm thick gold gasket. The filter bank ofmore » low pass filter, notch filter, and Faraday isolator is used to reject the electron cyclotron heating high power at attenuation of 60 dB. The full frequency band is swept in 20 μs. The mixer output is directly digitized with sampling rate of 100 MSamples/s. The phase is obtained by using wavelet transform. The whole hardware and software system is described in detail and the measured density profile is presented as a result.« less