The aim of this paper is to confirm the existence of atmospheric pressure dielectric controlled glow discharge and to describe its main behavior. Electrical measurements, short time exposure photographs, and numerical modeling were used to achieve this task. Experimental observations and numerical simulation are in good agreement. Therefore, the analysis of the calculated space and time variations of the electric field together with the ion and electron densities helps to explain the discharge mechanisms involved, showing the main role played by the electron as well as helium metastable density just before the discharge is turned on.

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We report the results of an ongoing2 interdisciplinary collaboration formed to assess the sterilizing capabilities of the One Atmosphere Uniform Glow Discharge Plasma (OAUGDP). This glow discharge plasma is capable of operating at atmospheric pressure in air and provides antimicrobial active species to surfaces at room temperature as determined by viable plate counts. OAUGDP exposures have reduced log numbers of bacteria (S. aureus and E. coli), endospores ( B . pumilus and B . subtilis) and yeast (S. cerevisiae and C. albicans) on various porous and non-porous surfaces. These include polypropylene, filter paper, paper strips, solid culture media, and glass.Experimental results showed a greater than or equal to 5 log 10 reduction in bacteria in times ranging from 15 to 60 sec.Additional tests were done with bacteria in sealed sterilization bags with similar results. However, when bacteria were embedded in agar, a greater than or equal to 5 log 10 reduction in numbers was seen in an extended time of 4 min. Plasma exposures of 5 min or less generated a greater than or equal to 5 loglo reduction of bacterial endospores and yeast tested. All microorganisms tested exhibited a bi-phasic survival curve when plotted on a semi-log plot. Several proposed mechanisms of killing at room temperature by the OAUGDP are discussed. ABSTRACTPreviously, we experimentally and numerically[ 11 demonstrated the existence and operation of the One Atmosphere Uniform Glow Discharge Plasma (OAUGDP) [2, Section 12.5.21. In this discharge, the electron energy and density, as well as other plasma characteristics, are functions of time. This timedependence is best studied by computer modeling, and has been extensively carried out