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[en] The quasiperiodic chaos in an undriven discharge plasma has been investigated experimentally. Results from the power spectrum and Lyapunov exponents quantitatively confirm the transition to chaos through the quasi periodicity. A low dimension strange attractor has been found for this kind of plasma chaos
[en] A swept-frequency X-mode reflectometer is being built for Alcator C-Mod to measure the scrape-off layer density profiles at the top, middle, and bottom locations in front of both the new lower hybrid launcher and the new ion cyclotron range of frequencies antenna. The system is planned to operate between 100 and 146 GHz at sweep rates from 10 μs to 1 ms, and will cover a density range of approximately 1016-1020 m-3 at B0=5-5.4 T. To minimize the effects of density fluctuations, both differential phase and full phase reflectometry will be employed. Design, test data, and calibration results of this electronics system will be discussed. To reduce attenuation losses, tallguide (TE01) will be used for most of the transmission line system. Simulations of high mode conversion in tallguide components, such as e-plane hyperbolic secant radius of curvature bends, tapers, and horn antennas will be shown. Experimental measurements of the total attenuation losses of these components in the lower hybrid waveguide run will also be presented.
[en] Radio frequency (RF) heating in the ion cyclotron range of frequencies (ICRF) is one of the primary auxiliary heating methods for EAST. The ICRF system provides 6 MW power in primary phase and will be capable of 10 MW later. Three 1.5 MW ICRF systems in a frequency range of 25 MHz to 70 MHz have already been in operation. The ICRF heating launchers are designed to have two current straps with each driven by a RF power source of 1.5 MW. In this paper a brief introduction of the ICRF heating system capability in EAST and the preliminary results in EAST are presented. (magnetically confined plasma)
[en] A two-frequency x-mode reflectometer operating from 100 146 GHz is being deployed on Alcator C-Mod to measure the density profile and fluctuations in the scrape-off layer (SOL) immediately in-front of the new J-port ICRF antenna and the new B-port Lower Hybrid launcher. The reflectometer will cover densities from 1016 to 1020 m-3 at 5 5.4 T. To provide the greatest flexibility and capability to deal with density fluctuations approaching 100% peak to peak in the SOL, both full-phase and differential-phase measurement capabilities with sweep speeds of ∼10 s to >1 ms are being implemented. The differential-phase measurement will use a difference-frequency of 500 MHz, corresponding to cutoff layer separations ranging from about 0.1 mm to 1 mm. The reflectometer will have 6 sets of launchers: 3 on the J-port ICRF antenna and 3 on the B-port LHRF launcher. The ICRF and LHRF antennas will incorporate reflectometer antennas at their top, bottom and mid-plane locations.
[en] Highlights: • A novel structure was designed to contain quantum dot solution. • The color rendering index was improved by adding the red-emitting AgInS2/ZnS QDs. • The liquid-type WLED has better performances in luminous efficiency and stability. We here report a warm white light-emitting diode (WLED) by employing the red-emitting liquid layer of AgInS2/ZnS quantum dots (QDs) over the yellow-emitting YAG:Ce phosphor-based WLEDs. Compared to the commercial WLEDs, our liquid-type QD-WLEDs exhibit a color temperature of 3500 K and an improved color rendering index of 85. In addition, the experimental results indicate that the liquid structure warm white light device has a higher luminous efficiency of 72.1 lm/W and a better color stability against the extended working time in comparison to the solid-type QD-WLEDs.