Influence of atmospheric ions on impulse corona discharge

The investigation was an attempt to control the primary ionisation in a gap to be subjected to an impulse potential. The technique consisted of the application of a steady potential to a rod electrode prior to the impulse wave. The initial population of ions will then be controlled by a drift process. If a negative-polarity drift field is applied to the rod, the time lag of the impulse corona discharge can be considerably delayed. The effect of a positive-polarity drift field is to shorten the time lag of the corona discharge. This polarity effect confirms the importance of negative ions as a source of primary electrons. The influence of electrode surface state and of the magnitude of the impulse voltage suggests that other sources of primary electrons may also exist. A quantitative analysis of the effect of a drift field on the ion density is also presented.