Tests of a full-scale ITER toroidal interferometer and polarimeter (TIP) prototype on the DIII-D tokamak (invited)

Autor: Ray O’Neill, P Mauzey, Jie Chen, D. K. Finkenthal, D. Du, Tsuyoshi Akiyama, Christopher Muscatello, Michael T. Watkins, D. L. Brower, Rick Wood, David Johnson, F. Glass, T. N. Carlstrom, Weixing Ding, M. Smiley, A. Gattuso, M. A. Van Zeeland, R. L. Boivin, A. Colio, C. Watts, J. Vasquez, M. Perry
Rok vydání: 2018
Předmět:
Zdroj: Review of Scientific Instruments. 89:10B102
ISSN: 1089-7623
0034-6748
Popis: A full-scale ITER toroidal interferometer and polarimeter (TIP) prototype, including an active feedback alignment system, has been installed and tested on the DIII-D tokamak. In the TIP prototype, a two-color interferometry measurement of line-integrated density is carried out at 10.59 μm and 5.22 μm using a CO2 and quantum cascade laser, respectively, while a separate polarimetry measurement of the plasma-induced Faraday effect is made at 10.59 μm. The TIP prototype is equipped with a piezo tip/tilt stage active feedback alignment system that minimizes noise in the measurement and keeps the diagnostic aligned throughout DIII-D discharges. The measured phase resolution for the polarimeter and interferometer is 0.05° (100 Hz bandwidth) and 1.9° (1 kHz bandwidth), respectively. The corresponding line-integrated density resolution for the vibration-compensated interferometer is δnL = 1.5 × 1018 m-2, and the magnetic field-weighted line-integrated density from the polarimeter is δnBL = 1.5 × 1019 Tm-2. Both interferometer and polarimeter measurements during DIII-D discharges compare well with the expectations based on calculations using Thomson scattering measured density profiles and magnetic equilibrium reconstructions. Additionally, larger bandwidth interferometer measurements show that the diagnostic is a sensitive monitor of core density fluctuations with demonstrated measurements of Alfven eigenmodes and tearing modes.
Databáze: OpenAIRE
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