Spatially periodic patterns in a dc gas-discharge system

Abstract

The evolution of spatially periodic patterns lateral to the current flow in a dc gas-discharge system consisting of a semiconductor and a metal electrode is reported. To explain these experiments a previously introduced two-layer model is used, which can be described by a system of reaction-diffusion equations. The discretized form of this system of equations can be interpreted as an equivalent electric circuit. Applying the center manifold theory to the system of equations, the experiments can be explained in terms of a bifurcation in that the system is undergoing a Turing diffusion instability. For the model, as well as in the experiments, the bifurcation from a homogeneous state into a spatially periodic structure is obtained by varying the externally applied voltage, the load resistance, or the width of the discharge slit. In connection with the application of the model to the gas-discharge system, the j(U) characteristic is measured for the whole discharge space and the positive column.