Fast imaging of transients and coherent magnetohydrodynamic modes in DIII-D
Fast imaging of transients and coherent magnetohydrodynamic modes in DIII-D
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DIII-D 中瞬态和相干磁流体动力学模式的快速成像
DOI：
10.1063/1.3118626
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
R. L. Haye
中科院分区：
文献类型：
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作者：
J. Yu;M. Zeeland;M. Chu;V. A. Izzo;R. L. Haye
快速分幅相机用于等离子体波成像及其在DIII-D托卡马克中的不稳定性[J]。卢克森，纽克。融合42,614(2002)]前所未有的细节，包括撕裂模式（TMs）和锯齿状碰撞。为了成像磁流体动力学（MHD）活动，快速相机在中至高密度等离子体中检测可见的轫致辐射eB。对于相干MHD活动，如TMs，通过傅里叶滤波在模态频率下每个像素的时间序列获得模态振幅和相位的高分辨率二维图像。m/n=2/1 TMs的图像表明，在q=2表面内，相机测量结果与平衡eB剖面上叠加的2/1岛的解析模型非常吻合。直接将测量结果与NIMROD模拟结果进行比较，可以发现显著的差异，这很可能是由于数值稳定性代码中使用的人为高密度扩散造成的。第一张瞬态锯齿状碰撞的可见光图像显示了它的结构和位置。
A fast framing camera is used to image plasma waves and instabilities in the DIII-D tokamak [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] in unprecedented detail including tearing modes (TMs) and sawtooth crashes. To image core magnetohydrodynamic (MHD) activity, the fast camera detects visible bremsstrahlung emission eB in moderate to high density plasmas. For coherent MHD activity such as TMs, high-resolution two-dimensional images of mode amplitude and phase are obtained by Fourier filtering each pixel’s time series at the mode frequency. Images of m/n=2/1 TMs show that inside the q=2 surface, the camera measurements are in excellent agreement with an analytic model of a 2/1 island superimposed on the equilibrium eB profile. Direct comparison of the measurements to a NIMROD simulation shows significant discrepancies, most likely due to artificially high-density diffusion used in the code for numerical stability. The first visible-light images of transient sawtooth crashes show the structure and location o...