The Trichel pulse is a typical kind of negative corona current. To further investigate Trichel pulse discharge characteristics

considering that it is difficult to study pulse because of the discharge randomness

we used a needle-plate electrode structure to study the characteristics of Trichel pulse in air under the condition of room temperature. Using the statistical methods

we analyzed the probability distribution of parameters of Trichel pulse

including the rising time

the half-wave time

the amplitude of pulse

and the pulse frequency. The results show that

during the period of applied voltage increasing

there is a mode transition. This transition process happens in a certain voltage region. Under the condition in this paper

the mode transition starts at the voltage of-6.5 k V

and ends at the voltage of-8 k V. In the period of mode transition process

the rising time and half-wave time is almost constant and the amplitudes of pulse will remarkably change. The change of amplitudes of pulses is the main difference between the two modes.