Studies on Nonlocal Bursty Transport of Plasma Heat and Particles in Toroidal Divertor Configuration

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1. Construction of Toroidal Device NAGDIS-T for SOL and Divertor Simulation StudiesMachine parameters are as follows: Major radius RO = 34 cm, width 2a =18 cm, Height 2b = 28 cm, Toroidal and vertical fields: Bt = 0.1 T, Bv = 10 G. The plasma density of ne~1018 m-3 and the electron temperature of Te~10 eV with the pulse length of 50 ms under the deuterium gas pressure of P~1 mTorr have been obtained by the injection of RF power of 20 kW for AC Joule heating. A simple numerical model for the plasma generation is employed and found to reproduce the gas pressure dependence of plasma density. A steady spiral toroidal plasma production using DC discharge of ne・1019 m-3 and Te~5 eV has been obtained for the prospect of ELM simulation by a pulsed operation.2. Research on bursty nonlocal transport of plasma heat and particlesStatistical analysis of time-series data with the help of probability density function, wavelet transform associated by complex Morlet mother function, and fractal analysi … More s becomes a very important tool for the present project owing to the contributions of Dr. Budaev.Radial velocity distribution function of intermittent bursty fluctuations observed in NAGDIS-II has been obtained. The velocity distribution with large amplitude at a specific range of of wavelet scale was also demonstrated, and the mean velocity is found as fast as 800 m/s.In. the properties of intermittent bursty fluctuations in JT-60U SOL, the skewness of Isat peaks around dsep = 60-80 mm where the direction of the mean parallel SOL flow changes upward to downward in both L-mode and between ELMs of ELMy H-mode. The radial decay length of Isat increases there. The decay length of Isat during ELM is about three times as large as one of Isat between ELMs. The ELMs seem like blobsThe fluctuations in HYBTOK-II tokamak plasma with dynamic ergodic divertor configuration (DED) tend to propagate poloidally and predominantly in accordance with the DED rotation direction, something like chaos control. Less