Under certain circumstances, plasma tends to form structures - filaments of electric discharge that are like mini-lightning. Researchers recently investigated barrier discharge, which features at least one electrical insulating material within the discharge gap that acts as an electrically insulating barrier and can be used as a plasma source. They investigated the transition from a highly ordered filament pattern, which is arranged hexagonally, to a disordered system due to the reduction of the externally applied voltage.
To analyze the transition in the order of the discharge, Drs. Robert Wild and Lars Stollenwerk from the University of Greifswald used two approaches: First, they used 2-D Fourier transformation, commonly employed to analyze spatial patterns. Then they applied an analysis tool typically used to evaluate dusty plasma discharges, known as triple correlation function. The latter approach offers the advantage of considering only the positions of the nearest neighboring filaments and of disregarding their actual geometry. As a consequence, it is used to estimate the probability of finding a second filament at a certain angle and distance from a first filament.
The authors observed a pivot point in the voltage at which the decaying order started occurring. This information can ultimately be used to guarantee the quality of applications such as plasma screens. That is because the dissolution of self-organized electric discharge filaments in plasma matter enhances the homogeneity of the matter.
Citation: R. Wild, L. Stollenwerk (2012), Breakdown of order in a self-organised barrier discharge, European Physical Journal D; DOI 10.1140/epjd/e2012-30220-4