Spatio-temporal response of stochastic resonance in an excitable dischargeplasma

Stochastic resonance is experimentally studied in a discharge plasma which is operated close to the threshold of ionization instability. It is shown t hat ionization wave-trains are excited by noise superimposed on the dischar ge current. There is a maximum signal-to-noise ratio at an optimum level of noise, indicating stochastic resonance. The corresponding spatio-temporal dynamics is investigated and it is shown that noise drives the stable disch arge stochastically into the convectively unstable regime. This also reveal s similarities to other physical system, for instance chemical waves. (C) 1 999 American Institute of Physics. [S1070-664X(99)03708-8].