Measurement System


Gold Neutral Beam Probe

 (1)   Gold Neutral Beam Probe at Central Cell

  The gold neutral particle is injected into the plasma, and the energy and intensity of ionized beam are analyzed. The diagnostics system is unique development and applies the broad range of GAMMA 10 plasma with unsteady leakage magnetic field. The information of radial potential profile, the phase difference between the potential and density fluctuations and magnetic field fluctuation are obtained by GNBP. The three types of GNBPs are established at central, barrier and inner mirror throat cells, respectively.


(2)   Gold Neutral Beam Probe at Thermal Barrier Cell

  The GNBP system applies to measurement of potential and its fluctuation at thermal barrier cell.


(3)   End Loss Energy Component Analyzer

  It is possible to measure the ion confinement potential and end loss ion velocity distribution.



Microwave Diagnostics

  The movable horn type interferometer which measure the radial density profile and the multichannel microwave interferometer which can measure the radial density profile at one plasma shot are established for density measurement. The density fluctuations are measured by using the multichannel microwave interferometer, ultra short pulse reflectometer, two-dimensional phase imaging method, and Fraunhofer diffraction method.


   70 GHz Microwave interferometer

 The density is measured by using 70 GHz microwave interferometer established at eight sections. In particular, it is possible to measure the plasma density profile at central cell by using the movable horn type interferometer and multipoint microwave interferometer.



Ultra short pulse reflectometer

  The plasma reflects the electromagnetic wave in which the frequency is lower than the frequency determined by electron density. The electron density and its fluctuation are obtained by observing the reflective wave with changing the incident wave frequency. The density and its fluctuation can be measured in one plasma shot by using the ultra short-pulse reflectometer which has wideband electromagnetic wave.




 Fraunhofer diffraction method (FD method)

It is possible to obtain the wave number and frequency of density fluctuation by measuring the  Fraunhofer diffraction.









Two-dimensional phase imaging method

  It is possible to measure the two-dimensional electron density profile with arranging the detectors in a matrix array.




Spectral diagnostics

  The spectral diagnostics are carried out by using Ha line emission detector array system, ultraviolet-visible spectroscopic measurement systems, vacuum ultraviolet and soft x-ray spectrograph systems. Ha line emission detector array systems can measure the neutral particle (hydrogen) density radial profiles. The plasma parameters and radiation loss are studied from the space distribution of impurity radiation spectra by using the ultraviolet-visible spectroscopic measurement systems and vacuum ultraviolet and soft x-ray spectrograph systems.



Two-dimensional Ha line emission detector array system

  The hydrogen atomic density and particle confinement time are studied by measuring the radiation due to the hydrogen atom.




Ultraviolet-visible spectroscopic measurement system, Vacuum ultraviolet spectrograph, Soft x-ray spectrograph

 The time- and space-distributions of radiation spectra are measured by using the two-dimensional spectral diagnostic systems correspond to each wavelength band which consists of ultraviolet-visible, vacuum ultraviolet and soft x-ray.



Thomson scattering diagnostics system

  The Thomson scattering diagnostic system is installed for measuring the electron temperature. The Nd:YAG laser (wavelength: 1064 nm, 2J/pulse, 10Hz, f 1mm) is injected into the plasma. The 90°Thomson scattering light is focused to optical fiber by using concave mirror (curvature radius: 1200 mm, f 600 mm), and lead to the five channel polychromator with avalanche photo diodes.