Electrohydrostatics in pin-to-plate gas discharge system

Electrohydrostatics was investigated in a pin-to-plate discharge system that consisted of the rigid pin electrode made of metal and the ion-conductive water electrode. At the dark discharge region, because extremely small electrostatic pull force, Coulomb force in the order of 10 μN, was induced, water shifted upward in the order of several 10 μm at the opposite center to the pin electrode. Over a threshold voltage corona discharge took place and a relatively large repulsive force, in the order of 100 μN, was induced due to the ionic wind. It depressed water and a large depression of water, in the order of several 100 μm at the center, was observed even to the naked eye. This phenomenon was named "Electrostatic Moses Effect." Deformation of the water level coincided with the pressure distribution on the metal plate electrode, if the surface tension of water and Coulomb force was included in the estimation to derive pressure distribution from the measured deformation of the water level. At the dark discharge region total force to the water electrode coincided with that to the pin electrode. However, it was larger than that to the pin electrode at corona discharge, because the reaction force due to the ionic wind was applied not only to the pin electrode but also to other part of the opposite electrode at the corona discharge.