Comparison of spatial and temporal characteristics between microplasma jet arrays and a single macroplasma jet

When low temperature plasma is generated in a flowing gas system, interactions with a material surface provide a versatile candidate for biochemical processing. By controlling the surrounding medium or tailoring the input gas, specific radicals and excited species can be produced within the plasma, which greatly benefit its applications in medical therapeutics and materials processing. The propagation of plasma jets into atmospheric pressure air is accompanied by spatially and temporally-resolved emission profiles that have been compared between microplasma jet arrays and a single macroplasma jet having the same cross-sectional area. The plasma-background gas interaction surface area, over which where plasma chemistry reactions occur has been significantly increased with a microplasma array. Multiple ionization bullets, with velocities of 0.3 -0.5 km/s, have been produced from a microchannel with a diameter of 355 μm. An order of magnitude increase in the velocity of the plasma jets has been observed by inserting a ground electrode and a dielectric barrier downstream to the jet aperture. The shape and velocity of propagation can be strongly influenced by the design of the jet aperture and the external ground. Spatial emission profiles confirm the advantage of large area treatment of tissue or a material surface with the microplasma array. The details will be discussed.