Parametric conditions for generation of stable atmospheric pressure nonthermal plasmas

Abstract

Nonthermal plasmas generated at atmospheric pressure have recently found many applications such as surface cleaning and pollution control. One plasma generation configuration consists of two dielectrically insulated parallel plates with application of an AC voltage of several kV and several kHz. Such a plasma generating structure is very similar to many HV insulating systems and equipment and as such they share much similarity in the evolving plasma and associated plasma-structure interaction. In this contribution, we develop a one-dimensional numerical model to simulate discharge plasmas supported by such an insulated electrode structure and for simplicity we consider helium as the working gas. Assuming that the hydrodynamic approximation applies, various ionization, excitation and recombination processes are considered as sources of generation of charged particles and excited species. Boltzmann equations are then solved in conjunction with the Poisson equation. Numerical examples are then used to explore the conditions under which the induced plasma is nonthermal. Also studied is the dependence of the plasma upon frequency of the applied voltage and the pressure of the ambient gas. These correlative relationships should also be true for many insulating devices and systems.