Initial pressure of the shock front launched by a streamer discharge in water

A streamer discharge in water launches a chain of isolated shock fronts as the streamer filament propagates through the water. The initial pressure of the shock front is a good estimation of the initial pressure of the streamer filament. We observed the temporal evolution of the shock front launched by a microsecond pulsed positive streamer discharge in water and investigated the initial pressure of the shock front. We discovered a method for determining the radius of the shock front measured from different discharge pulses in an accurate time sequence and obtained the temporal evolution of the shock front radius. Based on the measured temporal evolution of the shock front radius, we obtained that the initial pressure of the shock front is ∼0.6 GPa. We found that applied voltage and water conductivity do not affect the initial pressure of the shock front within the range studied.