Giant sawtooth oscillations in the Doublet III tokamak
Large-amplitude sawtooth oscillations have been observed in the soft-X-ray emission, central electron temperature, neutron production rate, radiated power, Dα emission, fast-neutral flux and one-turn voltage during beam-heating experiments in the Doublet III tokamak. The necessary conditions for the appearance of giant sawteeth seem to be operation at low qa and high βT. Many features of the giant sawteeth have been simulated with a transport code to which a sawtooth mixing model and several diagnostic models were added. Substantial redistribution of particles and energy evidently occurs over the plasma interior. Global energy confinement, however, is only moderately degraded by the sawteeth.
This study investigates the effects of Pierson-Moskowitz, Jonswap spectrum that are typical irregular wave spectrums for wind turbine system with jacket support structure. Also various offshore environmental parameters based on korean local condition were used in our study. The loads acting on the system was considered by referring to the Design Load Case from IEC guide line. And improved von Karman model was used as a turbulence model. As a result, various significant wave height and peak spectral period cause noticeable difference of extreme and fatigue loads prediction.