Stable atmospheric glow discharges: computational study and applications

This thesis describes a study of stable atmospheric pressure glow discharges through both a PC-based numerical simulation of their dynamics and exploratory experiments for establishing their decontamination efficacy. The numerical work is based on a one-dimensional fluid model with a commonly adopted hydrodynamic approximation that assumes electron equilibrium with the local electric field. Two gas systems are considered, namely pure helium and helium-nitrogen mixture, and our simulation results agree well with relevant experimental data. Also the numerical study establishes a specific frequency range within which stable helium atmospheric pressure dielectric-barrier glow discharges can be generated, and unravels two distinct plasma disruption mechanisms when the plasma excitation is outside the above mentioned frequency range. Further explored is possible plasma power saving that can be achieved by means of pulsed excitation. It is shown that significant power saving of up to 40% can be achieved by a combination of wave-shaping and pulse-width reduction. Finally through preliminary exploratory experiments, it is shown that atmospheric pressure glow discharge is biologically lethal to food-borne microorganisms and when further developed can form the basis for a novel food decontamination technology.