Production of CW high-density non-equilibrium plasma in the atmosphere using microgap discharge excited by microwave

A new technique for cw production of high-pressure, high-density. non-equilibrium plasma is presented. Using microwave excitation at 2.45 GHz. a stable atmospheric glow discharge was sustained between two knife-edge electrodes, having a length of 10 mm and facing each other across a similar to 100 mum microgap. Laser Thomson scattering diagnostics indicates that the plasma density in the microgap is as high as 1.6 x 10(15) cm(-3) at a microwave power of 100 W. The optical emission of the N-2 second positive band indicates that the gas temperature in the microgap is 1800 K, much lower than the electron temperature.