Experimental Estimation of Dust Generation Under ELM-Like Transient Heat Loads in Divertor Plasma Simulator-2

Although plasma-facing components composed of tungsten are less likely to generate dust when compared to other materials, dust generation is still possible during severe transient phenomena in fusion devices. The generation of tungsten dusts was experimentally investigated by exposing tungsten targets to a transient heat flux factor (F_HF) simulated by a high-energy pulsed laser so that the rate of dust generation would be analyzed. The rate of dust generation is observed to be increased linearly with respect to F_HF: G [mg/min] = C (F_EX – F₀), where F_EX is the experimental value of F_HF, F₀ is the threshold F_HF, and C [mg∙m²∙s^1/2/min∙MJ] = 0.0031 ± 0.0002. F_HF indicates that the characteristics of dusts such as size and F_HF are similar to those observed in several toroidal fusion devices. The threshold of F_HF for dust generation was also observed as 41 MJ/m²∙ s^1/2, which is similar to that of the international thermonuclear experimental reactor ITER (50 MJ/m²∙ s^1/2).