Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
Department of Physics, Wheaton College, Wheaton, Illinois 60187, USA.
Phys Rev Lett. 2018 Oct 19;121(16):165002. doi: 10.1103/PhysRevLett.121.165002.
The first direct measurements of an impurity particle flux driven by drift-wave turbulence in a toroidal magnetized plasma are reported. The correlation between the impurity density and radial velocity fluctuations is measured using ion Doppler spectroscopy. The small, very fast radial velocity fluctuation is resolved with the aid of a new linearized spectrum correlation analysis method that rejects uncorrelated noise as the sample size increases. The measured C^{2+} turbulent impurity flux in the edge of the plasma is directed inward and is consistent with impurity density measurements. This is also the first direct evidence for fluctuation-induced transport due to trapped-electron-mode turbulence in reversed field pinch plasmas.
首次直接测量到了由环形磁化等离子体中的漂移波湍流驱动的杂质粒子通量。使用离子多普勒光谱法测量了杂质密度与径向速度波动之间的相关性。借助一种新的线性谱相关分析方法，在样本量增加时排除不相关噪声，从而解析出非常小的快速径向速度波动。在等离子体边缘测量到的向内指向的 C^{2+}湍流杂质通量与杂质密度测量结果一致。这也是在反场点等离子体中因俘获电子模湍流导致的波动诱导输运的首个直接证据。
