Robert W Stark

US Patent:

6433480, Aug 13, 2002

Filed:

May 27, 2000

Appl. No.:

09/579875

Inventors:

Robert H. Stark - Norfolk VA
Karl H. Schoenbach - Norfolk VA

Assignee:

Old Dominion University - Norfolk VA

International Classification:

H01J 6104

US Classification:

313631, 313306

Abstract:

This invention improves the stability and control of high-pressure glow discharges by means of a microhllow cathode discharge. The microhollow cathode discharge, which is sustained between two closely spaced electrodes with an opening formed in the electrodes, serves as a plasma cathode for the high-pressure glow. Small variations in the microhollow cathode discharge voltage generate large variations in the microhollow cathode discharge current and consequently in the glow discharge current. In this mode of operation the electrical characteristic of this invention resembles that of a vacuum triode. Using the microhollow cathode discharge as a plasma cathode, stable, dc discharges in argon up to atmospheric pressures can be generated. Additionally, parallel operation of these discharges allows for the generation of large volume plasmas at high gas pressure through superposition of individual glow discharges. Thus, this invention allows simultaneous generation of relatively high electron densities at relatively low temperatures with stable, direct current, homogenous glow discharge plasma at relatively high pressure.