Numerical investigations on strong pattern selecting Eckhaus instabilities in neon glow discharges

Starting from the hydrodynamic description of the positive column in a neon glow discharge, a numerical approach is used in order to study the nonlinear properties of ionization waves. Within the instability region of the homogeneous equilibrium state, a secondary instability of the Eckhaus type is found. Compared to the classical results, the plasma system shows some peculiarities, e.g., an asymmetric stability band and strong selection of periodic patterns. The dependency of the shape and the width of this band on the discharge parameters is investigated. The spatiotemporal dynamics connected with the transitions from the stability band to the instability region have been studied showing different behavior on the upper and lower border of the stability region. Normally a subcritical Eckhaus instability has been revealed. Moreover, at selected sets of plasma parameters the phenomenon of spatiotemporal intermittency is found. (C) 2000 American Institute of Physics. [S1070-664X(00)02202-3].