The ion plasma sheath in the DC atmospheric pressure barrier discharge

Summary form only given. Work has continued on the DC atmospheric pressure barrier discharge with emphasis on diagnostics. The atmospheric pressure barrier discharge uses moist unglazed ceramic electrodes in place of metal electrodes. This electrode configuration prevents the discharge from contracting into an arc. Air, helium, and nitrogen have been used. In helium, several liters of plasma have been obtained in the steady-state at a power input of 300 watts. Preliminary density measurements suggest an ion density of 10/sup 11/ per cc. At atmospheric pressure, the ion sheath over a negative probe has a different structure from the Bohm sheath in low-pressure discharges. The ion motion in the high-pressure case is diffusive, rather than ballistic. Fortunately, the equations are readily solved in the planar case.