An experimental parametric study is made to investigate how the electrical corona discharge characteristics are influenced by the geometrical configuration and dimensions of the reactor and the electrode polarity of the applied voltage. Furthermore, features of the corona discharge plasma formed around the stressed electrode in some different gases are recorded photographically to provide more information on the physical mechanisms of the corona discharge in the investigated gases. The obtained results have been discussed in the light of gas discharge physics and its applications.

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Corona discharges in gases exist under several distinctive forms. In this paper, a survey study has been made of ac corona discharge modes generated in some different gases fed in a wire-duct reactor with a constant rate of flowing at atmospheric pressure. The properties of different corona modes are analyzed under some condition transitions from Trichel pulses to a steady glow. In the course of the presented experimental work, numerous apparent contradictions with earlier observations necessitated further study and are given to provide more information on the physical mechanisms of the ac corona discharges. Furthermore, we have gained insight into some new technologies and applications of the environmentally friendly corona and plasma discharges.

Mechanism's effect of transversal magnetic field on the populations of excited states of He atoms has been investigated. Furthermore, the dependencies of complete absorption of He(I) spectral line transition 33P0,1,2–23S1 on optical plasma density are calculated by numerical methods taking into consideration the fine-structure and Zeeman splitting schemes of the spectral lines. Using the calculated values and experimental results, the dynamics of the populations of He(I) metastable states 23S1 of the He nanosecond discharge are discussed.

A brief review is given on the role of dielectrics in gas discharge processes. Attention is focused on the key features of the charging mechanism of dielectric films on electrode surfaces and the subsequent breakdown of the discharge. It is experimentally shown that the explosion of surface dielectric films plays a decisive role in discharge voltage decrease. This is a direct result of the electric field distortion between the electrodes due to the accumulation of volume charge.