Study of the leader of a spark discharge over a water surface

This paper discusses an experimental study of the leaders of incomplete spark discharges with a capacitance of 0.1 and 1 µF over a water surface when the initial voltage is 3–6 kV in discharge gaps 8 and 22 cm long, having side branches and without branches. The distributions of the field, the current, the current density, the conductivity, and the electron concentration along the leader have been determined, as well as the changes in the velocity and length of the leader as it evolves. It has been established that the evolution of the leader has a self-maintained character, and that the product of the storage capacitance and the initial potential difference between the head of the leader and the water surface is an invariant of its spatial evolution.