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arXiv 1507.06555physics.plasm-ph
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MAST的二维多普勒后向散射观测

Observations of 2D Doppler backscattering on MAST

D. A. Thomas, K. J. Brunner, S. J. Freethy, B. K. Huang, V. F. Shevchenko, R. G. L. Vann

摘要:

合成孔径微波成像(SAMI)诊断已经在MAST上进行了原理验证2D多普勒反向散射(DBS)实验。SAMI使用宽(垂直和水平± 40度)和可调(10-35.5 GHz)光束主动探测等离子体边缘。多普勒后向散射信号是数字化的矢量形式使用一个阵列的八个Vivaldi PCB天线。这允许接收阵列在视场内的任何方向上同时聚焦到10- 34.5GHz处的6-24度FWHM的角度范围。这种能力是SAMI独有的,是进行DBS实验的一种全新方式。本文探讨了开展二维DBS实验的可行性。在常规DBS实验上观察到的现象的初步测量,如从中性光束的动量注入和功率和湍流速度的突然变化与H-模式的发病相一致。此外,能够进行2D DBS成像允许磁俯仰角的测量,提出了初步结果。能力通过转向波束使用相控阵列和这种技术的局限性进行了讨论。

英文摘要:

The Synthetic Aperture Microwave Imaging (SAMI) diagnostic has conducted proof-of-principle 2D Doppler backscattering (DBS) experiments on MAST. SAMI actively probes the plasma edge using a wide (+-40 degrees vertical and horizontal) and tuneable (10-35.5 GHz) beam. The Doppler backscattered signal is digitised in vector form using an array of eight Vivaldi PCB antennas. This allows the receiving array to be focused in any direction within the field of view simultaneously to an angular range of 6-24 degrees FWHM at 10-34.5 GHz. This capability is unique to SAMI and is an entirely novel way of conducting DBS experiments. In this paper the feasibility of conducting 2D DBS experiments is explored. Initial measurements of phenomena observed on conventional DBS experiments are presented; such as momentum injection from neutral beams and an abrupt change in power and turbulence velocity coinciding with the onset of H-mode. In addition, being able to carry out 2D DBS imaging allows a measurement of magnetic pitch angle to be made; preliminary results are presented. Capabilities gained through steering a beam using a phased array and the limitations of this technique are discussed.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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