The Application Of High-speed CCD On MHD Instabilities Diagnosis

Controlled nuclear fusion is the most promising efficient and clean energy resource of next generation. Realization of peaceful use of the controlled nuclear fusion energy will benefit to mankind and become an important subject in energy research around the world. In magnetic confinement fusion research, tokamak is considered to be one of the most likely to achieve controlled nuclear fusion. In tokamak research, a variety of plasma diagnostic techniques and methods are used to measure and analyze the physical processes and mechanism in plasmas. Exploration and development of advanced diagnostic techniques and measurement methods has been an important research subject of the fusion plasma research.According to the experimental research necessary in T-7and EAST superconducting tokamaks, a high-speed CCD(charge-coupled device) plasma imaging diagnosis system is setup in the tokamaks. Two high-speed cameras are used in the system, one is a color camera, MS75K from Mega Speed Corp, with maximum6K fps shooting speed in its full504x504pixels,,the other is a monochrome camera Phanton v710from Vision Reserch Corp and maximum7.5K fps shooting speed in1280x800pixels, and can achieve up to700k fps by reducing resolution. The details of the system construction and control software are present. By using the fast CCD imagine system,the following studies are carred out:The study of the plasma discharge image edge detection method. Plasma boundary detection is an important part in the feedback control of tokamak plasma start-up period.,According to characteristics of plasma start-up positon image, the improved Snake boundary detection and tracking algorithm are introduced. The plasma boundary position and the plasma central position are obtained by least-squares method to fit the boundaries. The results provide the condition for realization the start-up plasma positon feedback control in future. Study of diagnosis on MHD instabilities by high-speed CCD. Owing to its easy to use and good data visualization, CCD as a highly sensitive two-dimensional emission measuring detectors, is very suitable to measure and study of the physical phenomena with spatial and temporal distribution in tokamak plasmas..Using high-speed CCD to diagnostic MHD instabilities is reported. Sawtooth and Mirnov oscillations in HT-7tokamak and ELM process in EAST H-mode discharges are measured by CCD. The primary experimental results provide the base for further space and time evolution study of MHD instabilities by using high-speed CCD diagnosis.