Triggering of Negative Corona

Abstract. The parameters of both low-current and high-cment modes of DC negative corona discharge are described. The experiments were carried out in point-plane gaps in stagnant media of pure nitrogen, nitrogen, ambient air and in a dust-free air flow. A number of different types of point electrodes were used, including points covered by layers of TiOz and HfOz of controlled thickness. An overview of different methods of the triggering of the high-current mode is given. Discharges were initiated using x-ray radiation, laser radiation, UV radiation from different sources, and flux of positive ions. The correspondence of the model of dielectric switching mechanism as the triggering mechanism of high-current mode to the experimental results is discussed. Besides, the possible mechanisms limiting the repetition rate of Trichel pulses at its lower values (< 1 d s- ' ) are analysed. 1