Stable microplasmas in air generated with a silicon inverted pyramid plasma cathode

Stable microdischarges, ∼0.5-1 mm in length, are produced in atmospheric air by extracting plasma from a (50 μm)² inverted pyramidal Si microdischarge device which serves as a plasma cathode. Both metal and dielectric tips have been successfully tested as the extraction electrode and driving frequencies up to 20 kHz have been demonstrated. The plasma column, or conduit, generated is well behaved and essentially cylindrical with a diameter smaller than the width of the Si cathode device.