Development of Spark in Air from a Negative Point

Abstract

An old phenomenon used as a new detecting and diagnostic technique has been applied to the study of the voltage breakdown of air between a point cathode and a positive plane. ``Feathers'' were found to propagate at velocities almost 5% of the velocity of light. When they approach the positive plane, they produce ``retrograde streamers'' that bridge the gap and eventually lead to the completion of a plasma channel of high conductivity.