A new, versatile, direct-current helium atmospheric-pressure glow discharge

A novel direct current glow discharge sustained in helium at atmospheric pressure has been developed. Current - voltage behavior and spectroscopic characteristics strongly suggest that the system operates in the glow regime, in spite of the high pressure. The diffuse and extremely stable discharge is typically operated within a voltage range of 300 - 900 volts ( in the current- controlled mode) and at currents ranging over tens to hundreds of milliamps. Spatially resolved spectroscopic measurements of some selected species are presented. Rotational temperature pro. les were calculated using the OH emission spectrum, yielding values in the positive column ranging from 1300 to 1600 K.