Observation of microdischarge formation in Al/Al2O3 microchannel ozone generators with different cross-sectional structure

Summary form only given. Arrays of low temperature microplasma channels for ozone generation in air and O2 has been demonstrated recently. Fabricated from aluminum foil by wet chemical processing, micropowder ablation, and one photolithographic step, arrays of microchannel plasma devices 3 cm in length and 250 μm in width at the aperture of the channel produce spatially-uniform glow discharges in O₂ feedstock gas at a pressure of 1 atmosphere and flow rates of 0.25 - 2.5 liters per minute. This presentation reports the observation of discharge mode formation inside the microchannel in Ne, N₂ and air flow by optical microscopy and spectroscopy. Also, spatially resolved emission intensity in the cross-section of these microchannels is investigated by an intensified CCD camera with a telescope. The micrographs shows reasonably uniform power deposition in the cavity for Ne but a clear inability of the plasma to utilize the lowest portion of the cavity where numerical simulations show the electrical field strength to be at it weakest point. In the case of ambient air, visible emission intensity from the plasma is not uniform but the plasma does occupy virtually all of the cavity. Also, the microdischarge performances in different dielectric materials used for construction of the channel structure will be reported.