A linear array of point coronodes for negative corona discharge

Negative corona discharge from a novel linear metal point array structure has been investigated. The inherent advantage of using such a structure is that its rigidity eliminates vibration and sagging problems experienced by conventional wire corona emitters. More importantly, it is found that longitudinal current emission more uniform than that from wire emitters can be obtained by sufficiently reducing the point spacing of the point array. This current uniformity is stable with time. The current emission by the point array is proportional to V(V -V₀), where V₀ is the threshold voltage for corona discharge. The lateral current distribution can be described by Warburg´s law. Observation of corona glow in the dark indicates that discharge occurs at each point for large point spacings. When the point spacing is reduced to less than 2 mm, corona glow occurs generally at alternate points at intermediate field strengths and at every point when the field strength is raised further. A qualitative explanation of the different corona glow situations is given