Plasma-target surface interaction during non-equilibrium plasma irradiation at atmospheric pressure: Generation of dusty plasma

Abstract

The remaining challenges, developing the relativistic electron beam sources, stimulate the investigations of cathode materials. Carbon-fiber-aluminum composite is the most appropriate cathode materials to construct the robust relativistic electron beam sources. Carbon-fiber-aluminum composite is treated by a non-equilibrium atmospheric plasma torch with a copper electrode based on high-voltage gas discharge. The axial and radial distributions of the plasma torch temperature are measured to determine the optimal treatment temperature and location. Copper-oxide particles with diameters of less than 1 µm are deposited onto the surface of the carbon-fibers and a layer of copper-oxide covers the entire surface as the treatment time is increased. Raman spectroscopy suggests that although the locations of the D and G band are similar, the areas of the D and G bands increase after the plasma treatment due to the reduced graphite crystalline size in the carbon-fibers. Analysis of the copper electrode surface discloses materials ablation arising from the discharge which releases copper from the source. Our results reveal that the atmospheric plasma torch generated by high-voltage discharge is promising in the surface modification of the carbon-fiber-reinforced aluminum composite. Further, the plasma produced by atmospheric plasma torch is dusty plasma, due to the participation of liberated copper particles. The plasma torch was analyzed by fluid dynamics, in terms of plasma density, plasma expansion velocity, and internal pressure, and it was found that the plasma produced by atmospheric torch is supersonic flow.

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“…Another explanation is that FAME at low temperatures was more viscous than FAME at higher temperatures, which could significantly impede the physical exchange between subsurface oil and surface layer during the plasma reaction 29 . For the plasma torch, the energy released by the discharge was converted into heat, which raised the temperature of the expelled plasma torch 45 . The higher temperature has the effect of accelerating gas expansion to increase the plasma jet velocity 46 .…”

“…29 For the plasma torch, the energy released by the discharge was converted into heat, which raised the temperature of the expelled plasma torch. 45 The higher temperature has the effect of accelerating gas expansion to increase the plasma jet velocity. 46 For the 110 C case, the system was overheated, accompanied by the occurrences of sparks and arcs.…”