Hillesheim J C, Peebles W A, Rhodes T L, Schmitz L, White A E, Carter T A
Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, California 90095-1547, USA.
Rev Sci Instrum. 2010 Oct;81(10):10D907. doi: 10.1063/1.3466900.
A novel multichannel, tunable Doppler backscattering (DBS)/reflectometry system has recently been developed and applied to a variety of DIII-D plasmas. Either DBS or reflectometry can be easily configured for use in a wide range of plasma conditions using a flexible quasi-optical antenna system. The multiple closely spaced channels, when combined with other fluctuation diagnostic systems, have opened up new measurements of plasma properties. For example, the toroidal and fine-scale radial structure of coherent plasma oscillations, such as geodesic acoustic modes, have been probed simultaneously in the core of high temperature plasmas by applying correlation analysis between two toroidally separated DBS systems, as well as within the multichannel array. When configured as a reflectometer, cross-correlation with electron cyclotron emission radiometry has uncovered detailed information regarding the crossphase relationship between density and temperature fluctuations. The density-temperature crossphase measurement yields insight into the physics of tokamak turbulence at a fundamental level that can be directly compared with predictions from nonlinear gyrokinetic simulations.
最近开发了一种新型多通道、可调谐多普勒背散射（DBS）/反射测量系统，并将其应用于各种DIII-D等离子体。使用灵活的准光学天线系统，DBS或反射测量都可以轻松配置，以用于各种等离子体条件。多个紧密间隔的通道与其他波动诊断系统相结合，开启了对等离子体特性的新测量。例如，通过应用两个沿环向分离的DBS系统之间以及多通道阵列内的相关性分析，在高温等离子体的核心同时探测了相干等离子体振荡的环向和精细尺度径向结构，如测地声模。当配置为反射计使用时，与电子回旋辐射测量的互相关揭示了关于密度和温度波动之间交叉相位关系的详细信息。密度-温度交叉相位测量从根本层面深入了解托卡马克湍流的物理过程，可直接与非线性回旋动理学模拟的预测结果进行比较。
