Analysis of the behavior of ions produced by pulsed corona discharge

The motion of an ion cloud which is produced by a corona discharge with a high voltage pulse of a short duration and is introduced into parallel plate electrodes is calculated numerically. The ion cloud initially placed at the tip of a needle electrode is simulated by a number of ring charges and the trajectories of individual ring charges are calculated by using electric field strength obtained with a charge simulation method. Not only movement of the ion cloud but also the waveform of the induced current flowing through a ring electrode located at the center of the parallel plate electrode are simulated and analyzed. The ion cloud with an initial diameter of 0.5 mm expands to 5 mm by electrostatic repulsion within 10 μs after the beginning of drift. During drifting toward the counter electrode. The ion cloud extends wider to around the diameter of around 20 to 25 mm. The size and velocity of ion clouds agree with those estimated by experiments and the waveform of induced current obtained by experiments is reproduced by this simulation