Transversally accelerated kA arcs in air

Summary form only given. A transversally accelerated high pressure arc launcher is designed to initiate the Plasma Induced Lightening Experiment. The fundamental assumption after a current rise stage of around 10 MA/s is as follows. The arc is stable in shape and only the position is shifting to the Z direction along the electrodes separated d mm from each other. The arc area is covered by the ambient temperature boundary layer. In this way the arc and the boundary layer surrounding it are assumed to be an ambient temperature solid body as a whole. From these assumptions, the saturated arc velocity is V/sub B/=a d/sup - 1/2 / I. Here a is a constant in the order of 10/sup -3/ [m/sup 3/2//s/A] depending on the detailed geometrical factors. The actual experiment is conducted with a gap separation between 5 mm to 50 mm. The applied current is a crawbarred profile with 1.1 ms sinusoidal current ramp up to 10 kA and decays with a time constant of 6 ms. The arc position against time is displayed with the theoretical values obtained from our model. These results give a=2/spl plusmn/0.1 [m/sup 3/2//s/A]. This is in good agreement with our model.