Impurity emissivity tomographic reconstruction by CCD imaging system on J-TEXT

A tomographic reconstruction scheme of the tangential CCD imaging system was developed on J-TEXT, and the 2-D emissivity profile of CIII was obtained. Tomographic reconstruction was performed on the hypothesis that the emissivity is toroidally symmetric. Calibration of the CCD imaging system was completed by direct linear transfer(DLT), and the line-of-sight equations corresponding to each detector of the imaging system were obtained. The 2-D poloidal emissivity profile of CIII in the divertor configuration is obtained through Tikhonov regularization. The results of tomographic reconstruction show the evolution process of CIII emissivity in the divertor experiment and fit well with the magnetic flux surface calculated by equilibrium fitting code(EFIT).