An eight-channel Doppler backscattering system in the experimental advanced superconducting tokamak

作者：Hu, J. Q.; Zhou, C.; Liu, A. D.^*; Wang, M. Y.; Doyle, E. J.; Peebles, W. A.; Wang, G.; Zhang, X. H.; Zhang, J.; Feng, X.; Ji, J. X.; Li, H.; Lan, T.; Xie, J. L.; Ding, W. X.; Liu, W. D.; Yu, C. X.

来源：Review of Scientific Instruments, 2017, 88(7): 073504.

DOI：10.1063/1.4991855

• REFLECTOMETRY

Doppler backscattering system can measure the perpendicular velocity and fluctuation amplitude of the density turbulence with intermediate wavenumber. An eight-channel Doppler backscattering system has been installed in the Experimental Advanced Superconducting Tokamak (EAST), which can probe eight different radial locations simultaneously by launching eight fixed frequencies (55, 57.5, 60, 62.5, 67.5, 70, 72.5, 75 GHz) into plasma. The quasi-optical system consists of circular corrugated waveguide transmission, a fixed parabolic mirror, and a rotatable parabolic mirror which are integrated with quasi-optics front-end of the profile reflectometer inside the vacuum vessel. The incidence angle can be chosen from 5 degrees to 12 degrees, and the wavenumber range is 2-15/cm with the wavenumber resolution Delta k/k <= 0.21. Ray tracing simulations are used to calculate the scattering locations and the perpendicular wavenumber. The dynamic range of this new eight-channel Doppler backscattering system can be as large as 40 dB in the EAST. In this article, the hardware design, the ray tracing, and the preliminary experimental results in the EAST will be presented. Published by AIP Publishing.

• 单位
  合肥工业大学; 中国科学技术大学