Design of JT-60SA core Thomson scattering diagnostic system

Tojo, H.; Pasqualotto, R.; Fassina, A.; Giudicotti, L.; Sasao, H.; Homma, H.; Oyama, N.

doi:10.1063/5.0043669

Cited by 9 publications

(4 citation statements)

References 9 publications

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“…Two Thomson scattering diagnostics systems are being procured [19,20], one for core plasma measurement (46 points, R = 2.6-3.73 m) and one for the low field side (50 points, R = 3.70-4.17 m), also including the last closed flux surface. They will have high radial resolution, 25 mm in the core and from 25 down to 5.5 mm for the edge system for pedestal measurements.…”

Section: Plasma Diagnosticsmentioning

confidence: 99%

Completion of JT-60SA construction and contribution to ITER

et al. 2022

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Construction of the JT-60SA tokamak was completed on schedule in March 2020. Manufacture and assembly of all the main tokamak components satisfied technical requirements, including dimensional accuracy and functional performances. Development of the plasma heating systems and diagnostics have also progressed, including the demonstration of the favourable electron cyclotron range of frequency (ECRF) transmission at multiple frequencies and the achievement of long sustainment of a high-energy intense negative ion beam. Development of all the tokamak operation control systems has been completed, together with an improved plasma equilibrium control scheme suitable for superconducting tokamaks including ITER. For preparation of the tokamak operation, plasma discharge scenarios have been established using this advanced equilibrium controller. Individual commissioning of the cryogenic system and the power supply system confirmed that these systems satisfy design requirements including operational schemes contributing directly to ITER, such as active control of heat load fluctuation of the cryoplant, which is essential for dynamic operation in superconducting tokamaks. The integrated commissioning (IC) is started by vacuum pumping of the vacuum vessel and cryostat, and then moved to cool-down of the tokamak and coil excitation tests. Transition to the super-conducting state was confirmed for all the TF, EF and CS coils. The TF coil current successfully reached 25.7 kA, which is the nominal operating current of the TF coil. For this nominal toroidal field of 2.25 T, ECRF was applied and an ECRF plasma was created. The IC was, however, suspended by an incident of over current of one of the superconducting equilibrium field coil and He leakage caused by insufficient voltage holding capability at a terminal joint of the coil. The unique importance of JT-60SA for H-mode and high-β steady-state plasma research has been confirmed using advanced integrated modellings. These experiences of assembly, IC and plasma operation of JT-60SA contribute to ITER risk mitigation and efficient implementation of ITER operation.

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Section: Plasma Diagnosticsmentioning

confidence: 99%

Completion of JT-60SA construction and contribution to ITER

et al. 2022

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“…This T e value, around 13.5 keV, was obtained from simulation results by some transport codes for JT-60SA [14]. The wavelength ranges of the polychromator channels and the scattering angle for the core system of JT-60SA were assumed [3]. The channels are numbered from the closest wavelength to that of the Nd:YAG laser, 1064.2 nm.…”

Section: Simulation Of Thomson Scattered Signals For Jt-60samentioning

confidence: 99%

“…The Thomson scattering system requires a large number of measuring channels, which corresponds to a product of the number of the spectral channels and that of the spatial positions, in order to measure the electron temperature (T e ) and density (n e ) profiles. For example, the number of channels is 884 in the case of the Thomson scattering system for the Large Helical Device (LHD) [1,2] and it is more than 600 in the JT-60SA case [3]. A laser pulse which has the energy of a few joules is injected into the plasma and the scattered light is detected and dispersed by spectrometers.…”

Section: Introductionmentioning

confidence: 99%

Fast Signal Modeling for Thomson Scattering Diagnostics and Effects on Electron Temperature Evaluation

Funaba

Yamada

Yasuhara

et al. 2022

Plasma and Fusion Research

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As a signal processing method for fast digitizers of the switched-capacitor-type in Thomson scattering diagnostics, a "model fitting" method is proposed. An ideal shape of the signal is estimated by this method by averaging many Thomson scattering signals. After applying this method to a relatively low density LHD plasma, the scattering of electron temperature profiles becomes small. The magnitude of error is also reduced by about 60% at some spatial channels in the core plasma. Simulations of signals with some noises based on the JT-60SA Thomson scattering system enables a showing of the expected error in electron temperature. The error can be suppressed by the "model fitting" method.

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“…Thomson Scattering (TS) measurement is a crucial measurement for fusion plasma experiments to determine electron density and temperature with high spatial resolution by measuring the spectral distribution of TS light by injected laser. In JT-60SA, two systems, one for the core [1] and the other for the edge [2], are currently under development to evaluate plasma performance and understand physical phenomena.…”

Section: Introductionmentioning

confidence: 99%

Performance of JT-60SA Thomson Scattering data analysis system

Akimitsu,

Ohtani,

Funaba

et al. 2024

J. Inst.

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We have developed signal processing routines for the Thomson Scattering measurement, which is planned for use in the next campaign of the JT-60SA large-scale tokamak experiment. This paper provides the data analysis system and its performance evaluated in terms of computation time and error. The sequential routine of determining the scattered light intensity from a simulated signal, including noise data from a 1 Gs/s high-speed sampling digitizer, and determining the electron temperature and density was tested for the first time on an actual machine. The data analysis system ensures that electron temperature and density can be calculated with reasonable relative errors and within a realistic time frame for operations on JT-60SA.

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Design of JT-60SA core Thomson scattering diagnostic system

Cited by 9 publications

References 9 publications

Completion of JT-60SA construction and contribution to ITER

Completion of JT-60SA construction and contribution to ITER

Fast Signal Modeling for Thomson Scattering Diagnostics and Effects on Electron Temperature Evaluation

Performance of JT-60SA Thomson Scattering data analysis system

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