Charging, movement and lifetime characteristics of dust in magnetic fusion devices

Charging, movement and lifetime characteristics of spherical dust grains generated in magnetic fusion devices are discussed. A universal charging equation of the dust grain is given. The simulation results show that the charge quantity of the dust grain changes along with the ratio of electron and ion temperature, and decreases due to secondary electron emission, the charging relaxation time of dust grain in fusion devices is much shorter than that in laboratory plasma, that, under the effect of ion drag force, dust speed reaches hundreds of metres per second and the lifetime of carbon dust in fusion devices is at the millisecond scale. The results are consistent with experimental observations.