An analytical theory of corona discharge plasmas

Abstract

In this paper we describe an analytical investigation of corona discharge systems. Electrical charge and the energy transfer mechanism are investigated based on the circuit analysis. Efficient delivery of electrical energy from the external circuit to the reactor chamber is a major issue in design studies. The optimum condition obtained in this paper ensures 100% energy transfer. Second-order coupled differential equations are numerically solved. All the analytical results agree remarkably well with numerical data. The reactor capacitor plays a pivotal role in circuit performance. The voltage profile is dominated by the reactor capacitor. Corona discharge properties in the reactor chamber are also investigated, assuming that a specified voltage profile V(t) is fed through the inner conductor. The analytical description is based on the electron moment equation. Defining the plasma breakdown parameter u=V/Rcp, plasma is generated for a high-voltage pulse satisfying u>uc, where uc is the critical breakdown parameter defined by geometrical configuration. Here, u is in units of a million volts per m per atm, and Rc is the outer conductor radius. It is found that the plasma density profile generated inside the reactor chamber depends very sensitively on the system parameters. A small change of a physical parameter can easily lead to a density change in one order of magnitude.