Mode transition in dusty micro-plasma driven by pulsed radio-frequency source in C2H2/Ar mixture**Project supported by the Natural Science Foundation of Heilongjiang Province, China (Grant Nos. A2015011 and A2015010), the Postdoctoral Scientific Research Developmental Fund of Heilongjiang Province, China (Grant No. LBH-Q14159), the National Natural Science Foundation of China (Grant Nos. 11404180 and 11405092), and the Program for Young Teachers Scientific

Abstract

Physical qualities of dusty plasma in the pulsed radio-frequency C2H2/Ar microdischarges are carefully investigated by a one-dimensional hydrodynamic model and aerosol dynamics model. Since the thermophoretic force has a great effect on the nanoparticle density spatial distribution, the neutral gas energy equation is taken into accounted. The effects of pulse parameters (dust ratio, modulation frequency) on the nanoparticle formation and growth process are mainly discussed. The calculation results show that, as the duty ratio increases, the mode transition from the sheath oscillation (α regime) to the secondary electron heating (γ regime) occurred, which is quite different from the conventional pulsed discharge. Moreover, the effect of modulation frequency on the width of sheath and plasma density is analyzed. Compared with the H2CC ions, the modulation frequency effect on the nanoparticles density becomes more prominent.