Temperature measurement and simulation analysis of heaterless hollow cathode during start-up process

Monochromatic radiation thermometry is used to quantify temperature distribution during the start-up process for a heaterless hollow cathode. A transparent cathode is designed to facilitate the transmission of thermally and spontaneously radiated photons from the interior of the structure and their reception by the detection equipment. The relative radiation intensities can be obtained by the developed measurement equipment, which consists of an scientific complementary metal oxide semiconductor camera and a 780 nm narrow-band filter, and then transformed into temperature distributions calibrated by a two-color pyrometer. The current and voltage characteristics of the anode and keeper and plasma image captured by the high-speed camera are used to analyze the thermal evolution mechanism. A 2D extended fluid model coupling with a thermal model is also developed and used to help clarify the thermal deposition variation at different locations. These results provide further support for the hypothesis that thermal deposition of ions and electrons, thermal conduction, and thermal radiation all affect the rate of change in temperature of various components.