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One of the most promising candidates to produce clean nuclear fusion energy is the tokamak, a device magnetically confining an extremely hot plasma (i.e. an ionized gas) where the fusion reactions take place. To produce nuclear fusion energy using tokamak devices, it is crucial that the poloidal magnetic flux (characterized by the so-called q profile) and the plasma internal energy are tightly controlled...
We consider control of the q profile while simultaneously regulating the plasma stored energy for the DIII-D tokamak. The main objective is to improve the shot-to-shot reproducibility and facilitate the accessibility of operating conditions that have steady-state potential, i.e. plasmas with large non-inductive current drive fractions. At DIII-D, non-inductive current sources including electron cyclotron...
This paper briefly outlines the current status of CODAC system of the EAST tokamak. Integrated central system has been working for synchronizing all the subsystems and responsible for the integral safety protection by interlock. Data acquisition system has been established for the discharge with duration up to 100 seconds. Various data visualization tools such as EASTVIEWER to view the flux surfaces,...
Summary form only given. The core ion temperature and bulk ion velocity of ITER plasmas will likely be derived from the thermal Doppler broadening and Doppler shift of X-ray lines emitted by highly charged trace elements and recorded by an array of high-resolution spectrometers. Although several elements could be used to seed the plasma for this purpose, we show that the emission of neonlike tungsten...
A 4.6 GHz 3 MW lower hybrid current drive (LHCD) system has been designed and implemented on Alcator C-Mod. This RF system will allow C-Mod to access advanced tokamak regimes: high confinement, high betan, and high bootstrap fraction and extend them to quasi-steady-state conditions. The LHCD system includes twelve 250 kW klystrons. Power from each klystron is split eight ways using a complex system...
A lower hybrid current drive (LHCD) system has been developed for current profile control of advanced tokamak experiments on Alcator C-Mod. LHCD along with Ion Cyclotron Radio Frequency (ICRF) heating will be used to develop regimes with high confinement, high betan and high bootstrap fraction and extend them to quasi-steady-state conditions. This paper will describe the commissioning and initial...
Edge localized modes (ELMs), edge turbulence and other fluctuations in the edge region of NSTX plasma are observed by fast cameras. ELMs categorized as Type I, III, and V are found in NSTX and other MARFE-like activity is seen near the center stack in double null plasmas. Edge turbulence filaments are almost always found in NSTX. An interpretation of ELM images, which shows a complex ELMs structure,...
A multi-channel Thomson scattering system viewing the edge and core of the KSTAR plasma will be installed at the midplane port Bay-N. An engineering design study was undertaken at PPPL in collaboration with the Korea Basic Science Institute (KB Si to determine the optimal optics and cassette design. Design criteria included environmental, mechanical and optical factors. All of the optical design options...
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