Spatio-temporal response of stochastic resonance in an excitable discharge plasma

Stochastic resonance is experimentally studied in a discharge plasma which is operated close to the threshold of ionization instability. It is shown that ionization wave-trains are excited by noise superimposed on the discharge 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 discharge stochastically into the convectively unstable regime. This also reveals similarities to other physical system, for instance chemical waves. (C) 1999 American Institute of Physics. [S1070-664X(99)03708-8].