A full-scale 120m path length ITER toroidal interferometer and polarimeter (TIP) prototype, including an active feedback alignment system, has been constructed and undergone initial testing at General Atomics. In the TIP prototype, two-color interferometry is carried out at 10.59 μm and 5.22μm using a CO 2 and quantum cascade laser (QCL) respectively while a separate polarimetry measurement of the plasma induced Faraday effect is made at 10.59μm. The polarimeter system uses co-linear right and left-hand circularly polarized beams upshifted by 40 and 44 MHz acoustooptic cells respectively, to generate the necessary beat signal for heterodyne phase detection, while interferometry measurements are carried out at both 40 MHz and 44 MHz for the CO 2 laser and 40 MHz for the QCL. The high-resolution phase information is obtained using an all-digital FPGA based phase demodulation scheme and precision clock source. The TIP prototype is equipped with a piezo tip/tilt stage active feedback alignment system responsible for minimizing noise in the measurement and keeping the TIP diagnostic aligned indefinitely on its 120 m beam path including as the ITER vessel is brought from ambient to operating temperatures. The prototype beam path incorporates translation stages to simulate ITER motion through a bake cycle as well as other sources of motion or misalignment. Even in the presence of significant motion, the TIP prototype is able to meet ITER's density measurement requirements over 1000s shot durations with demonstrated phase resolution of 0.06°and 1.5°for the polarimeter and vibration compensated interferometer respectively. TIP vibration compensated interferometer measurements of a plasma have also been made in a pulsed radio frequency device and show a line-integrated density resolution of d = ńL 3.5 10 17 m −2 .
This study examined the relationship between coaching efficacy and imagery use. Eighty-nine coaches completed the Coaching Efficacy Scale and a modified version of the Sport Imagery Questionnaire. Results showed significant positive correlations among the coaching efficacy subscales and imagery functions. Regression analyses showed that the significant predictor for game strategy efficacy was CG imagery. Predictors for motivation efficacy included career record and MG-M imagery. MG-M imagery and total years of coaching were the significant predictors for total efficacy scores and character building efficacy. The only significant predictor for teaching technique efficacy was CS. The results replicate and extend the relationships found between efficacy and imagery for athletes and show that imagery also may be an effective strategy to build and maintain coaching efficacy.
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 Alfvén eigenmodes and tearing modes.
This paper provides an overview of high power components for the application of Electron Cyclotron Heating transmission lines, and broadband devices for Electron Cyclotron Emission detection systems. The unique fabrication and assembly challenges are discussed, particularly in the context of ITER. The ITER ECH system will require robust, vacuum-compatible components such as polarizers, dummy loads, and switches that are sufficiently cooled to withstand 1 MW for 3,600 seconds. These elements, along with overmoded corrugated waveguide, are necessary to form transmission lines with efficiencies of 90%, and 90% transmitted HE11 mode purity. Recent high power test results are summarized and scaled from the 63.5 mm internal diameter design to the 50 mm diameter version that will be used for ITER. Elements designed for Electron Cyclotron Emission detection and reflectometry systems are discussed, such as frequency filters and polarization rotators. The large frequency operating range of corrugated waveguide is exploited for such applications. The application of additive manufacturing technology towards both low and high power components is considered as a promising new area of development.
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