Effect of rate of current rise on the discharge uniformity: a two-dimensional simulation

Summary form only given, as follows. We report results of computer simulations of the development of a high-pressure discharge with several plasma channels. In simulations hot spots were initiated by small metal convexities at the cathode surface with a characteristic dimension of /spl sim/0.1 cm. The convexities cause the local electric field to be non-uniform. The convexity size determines degree of such a non-uniformity. It was shown that if the neighboring convexities have different size the total current switches to a larger plasma channel. Other channels vanish. With the increasing rate of the current rise all diffuse channels develop simultaneously. This takes place due to a fast increase of the electron density and depletion of the HCl molecules in the whole channel volume. Thus the improvement of the discharge uniformity can be achieved by an appropriate choice of the pumping regime.