EAST装置边缘局域模细丝宽度的高速CCD可见光相机系统诊断

Diagnosis of the width of ELMs filament by high-speed CCD visible camera-light system on EAST tokamak

利用高速CCD可见光相机系统研究了EAST上的边缘局域模(ELMs)细丝动力学特性。采用Tsai两步标定法对CCD相机进行标定,以实现将CCD图像坐标转换为真实空间坐标。选取CCD图像中与边缘局域模细丝垂直方向上的图像灰度值,绘制了灰度分布图。灰度分布图中的一个凸起的尖峰代表了一条边缘局域模细丝结构,细丝的位置坐标由尖峰顶点确定。运用Sobel边缘检测算子检测细丝边缘轮廓,从而得到细丝的宽度。通过对边缘局域模细丝宽度特性的分析,发现边缘局域模细丝在从最外层封闭磁面向外传播的过程中宽度不断减小。这表明细丝在向外传播的过程中其能量和粒子不断耗散。I-型边缘局域模的细丝宽度比III-型边缘局域模细丝的宽度更大。

The high speed CCD visible-light camera system has been installed to detect the dynamic characteristics of ELMs filaments on EAST tokamak.In order to convert the CCD video imaging coordinates into real space coordinates,the CCD system has calibrated using Tsai's two-stage calibration technique.A raised spike in the grayscale profile,drawn by selecting the grayscale value of the image in the vertical direction of the ELMs filament in the CCD image,represents an ELMs filament structure whose positional coordinates are determined by the apex of the spike.The Sobel edge detection operator was used to examine the edge profile of the filament to obtain the width of the filament.By analyzing the characteristics of the filament width of the ELMs,it is found that the width of ELMs filaments continuously decreases outward from the outermost magnetic surface.This indicates that the filaments continue to dissipate energy and particles as they propagate outward.The width of filaments of Type-I ELMs is greater than that of Type-III ELMs.