System validation of CO2 laser based Phase Contrast Imaging on HL-2A tokamak
System validation and density fluctuation calibration of Phase Contrast Imaging (PCI) on HL-2A tokamakare presented. Signals from different channels show not only a pronounced modulation of incident laser beam induced by sound wave but also an excellent magnification and low image distortion of optics. Frequency-wavenumber spectrum is achieved by using two-dimensional Fourier transform of time series signals. Conversion relationship between detected signal amplitude and chord integral plasma density fluctuation is 2.35×1013m-2/mV, which promises a suitable signal level at the order of Volts of the PCI in typical HL-2A discharges.
Yu Yi,Gong Shaobo,Xu Min,Yuan Boda,Wu Yifan,Nie Lin,Ke Rui,Ye Minyou,Duan Xuru. System validation of CO2 laser based Phase Contrast Imaging on HL-2A tokamak[J].Chinese Optics Letters,2018,16(12):12.