PROCEEDINGS ARTICLE | February 22, 2008

Proc. SPIE. 6622, International Symposium on Photoelectronic Detection and Imaging 2007: Laser, Ultraviolet, and Terahertz Technology

KEYWORDS: Molecular bridges, Argon, Electrodes, Photomultipliers, Dielectrics, Complex systems, High speed cameras, Bridges, Signal detection, Stochastic processes

Spatio-temporal patterns in nonlinear system have been paid much attention in resent years. Among different
nonlinear systems, gas discharge system is more remarkable because proper time scale and abundance in pattern
structures. In this article, pattern formation dynamics is studied in a dielectric barrier discharge system with mixed
working gas of argon and air at pressure of 0.6 atm by optical method. A boundary condition of square structure is used
in the experiments. The experimental results show that the discharge pattern with increasing the applied voltage
undergoes a scenario: uniform discharge, hexagon structure, stochastic micro-discharge filaments, hexagon structure
again, square pattern, regular stripes that bridge the boundary, and uniform discharge again. The emission signals from
the discharge in different pattern are detected by photomultiplier tubes and results show that the waveform of total light
signals under low voltage lower than the voltage of stochastic micro-discharge filaments is only one pulse at each half
cycle of the applied voltage, while it shows two pulses at each half cycle of the applied voltage in the second hexagon
pattern and square pattern, and more pulses appear in the stripe pattern discharge and second uniform discharge. Through
analyzing the temporal sequence of the different filaments in a hexagon, it can be concluded that the hexagon pattern is
an interleaving of two rectangular sub-patterns that the micro-discharge filaments in a sub-pattern volley almost at the
same time. The temporal sequence of the two sub-patterns in consecutive half cycle alternates.