Chaotic phenomena observed in DC glow discharge plasma

We report on the experimental studies of oscillatory phenomena observed in the direct current glow discharge with helium. The positive column of the direct current glow discharge is known to be unstable in wide range of the discharge parameters, such as the discharge current and the gas pressure. Consequently, the discharge current and the light intensity of the positive column fluctuate rapidly. in our experiment, with increasing of the discharge current, the discharge plasma exhibits the sequence of periodic, quasiperiodic, and chaotic state which includes frequency locking. To identify whether the observed oscillations are chaotic or not, spectral analysis. estimations of the correlation dimension and calculations of the largest Lyapunov exponents are performed.