Effects of micro-bubbles on leader formation

Vapp = 18 kV,
which is much less than discharge-sustain-voltage.
Electrical discharge cannot be ignited even for ten minutes after turning power on.

When micro-bubbles are supplied, leader-type electrical discharges are ignited, which means that the supply of micro-bubbles can reduce discharge ignition voltage (from conventional 30 kV down to 18 kV).