AbstractIn the present study, the behavior of ionized carbons during a simulated plasma disruption is investigated with the magneto-plasma-dynamic (MPD) arc jet. The MPD arc jet was improved to generate the high heat flux. The temporal and spatial distributions of the ionized carbons were measured by emission spectroscopy. The effect of heat load was evaluated using two pulses, i.e. the original and improved MPD arc jet. The C II and C III distributions were obtained for the two pulses. The emission intensities were strongly related to the evaporated flux of carbon.