| Research Abstract |
We proposed and discussed a mass limited mode in the methods of microplasma generation under atmospheric pressure. The plasma is generated using electrical discharges with any state of mater, namely, solid, liquid, and gas, having a small volume. It is common knowledge that plasmas are created mostly with gases. This, however, has altered in the field of microplasmas. For solids, the plasma was generated with a copper powder particle of 100mm in diameter by pulsed discharge. For liquids, a droplet or a filament of ethanol was used in pulsed discharges. The filament was grown from the tip of a Taylor cone, which was created by the electrostatic force between electrodes. In both cases, the plasmas were generated through the complicated process including heat, melt, vaporization, and ionization of materials. For gases, a miniature gas flow through a small metal nozzle developed to dc glow microdischarges in air. The working gas was helium or argon. The features of adopting the gas flow are that stable microplasmas with thin cylindrical structures are generated and any discharge modes, corona, glow, and arc discharges, are obtained with the same electrode system. The latter feature is useful for plasma applications and the analysis of discharge physics. We developed atmospheric dc microplasma generated along perpendicularly intersecting two miniature gas flows. This scheme enables us to obtain the microplasma in the outside of the narrow space between electrodes and, consequently, to develop a variety of applications. Discussing the plasma generation by pulse or radio-frequency power, we established high-power injection and deposition of diamond like carbon film on substrates. New schemes to generate electrolyte cathode glow discharge with the miniature gas flow were proposed and developed. Phenomena at the interface between the plasma and the solution will be used for the applications in chemistry and material science.
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