Ray Tracing for Doppler Backscattering System in the Experimental Advanced Superconducting Tokamak*supported by National Natural Science Foundation of China (Nos. 10990211 and 11105146) and the ITER-CN Project, 973 Program of China (No. 2013GB106002). (September 2015)

• Record Type: Journal Article
• Authors: Zhou, Chu; Liu, Adi; Hu, Jianqiang; Wang, Mingyuan; Zhang, Xiaohui; Li, Hong; Yu, Changxuan; Liu, Wandong; Lan, Tao; Xie, Jinlin
• Is Part Of: Plasma science and technology. Volume 17:Number 9(2015:Sep.)
• Page Start: 728
• Page End: 732
• Publication Date: 2015-09
• Subjects: Plasma (Ionized gases) -- Periodicals; 530.44
• DOI: 10.1088/1009-0630/17/9/02
• Languages: English
• ISSNs: 1009-0630

Abstract

<abstract> <title>Abstract</title> <p>The Doppler backscattering system has been widely used for turbulence measurements, and the microwave beam will be backscattered near the cut-off layer when the Brag condition is fulfilled. In tokamak, the ray-tracing code is used to obtain the radial position and perpendicular wave number of the scattering layer for turbulence velocity measurement and the WKB (Wentzel-Kramers-Brillouin) approximation should be satisfied for optical propagation. To calculate the backscattering location and wave number at the cut-off layer only, a single ray tracing in the cross section is enough, while for spatial and wave number resolution calculation, multiple rays reflecting the microwave beam size should be used. Considering the angle between the wave vector and the magnetic field, a three-dimension quasi-optical Gaussian ray tracing is sometimes needed.</p> </abstract>