Three-dimensional reconstruction of the excitation temperature of copper atoms in vacuum arcs

Excitation temperature of atoms attaches importance to understand the nature of vacuum arc plasmas. The traditional methods present the temperatures in one or two dimensions in space, but the results of the temperature distribution in three dimensions are crucial for understanding asymmetric plasmas. To address the issues, a 3D temperature reconstruction algorithm was proposed in this paper. First, a 3D tomographic optical platform based upon split fiber bundles was built to record the multi-angle arc images of CuI. Then, the 3D emissivity distribution at 510.6nm and 515.3nm was reconstructed, wherein A tomography algorithm named MLEM-SB was utilized. After that, the 3D excitation temperature distribution of CuI was calculated by the two-line method. The results show that the emissivity was higher at the center of the arc and lower at the edges, exhibiting characteristics of radial non-uniformity, and the emissivity at 510.6nm increases gradually from cathode to anode, while the emissivity at 515.3nm first increased and then decreased. With control of AMF, the maximum excitation temperature of CuI in the arc column was 9060 K at a peak current of 4 kA, and the temperature was higher at the center of the arc and lower at the edges.