Comparing Investigations On Formation Mechanism Of Glow And Streamer DBD Patterns

Dieletric barrier discharge is a kind of typical non-equilibrium plasma,which has great application potentials.It is also a system of high nonlinearity,in which abundant patterned nonlinear phenomena can be observed.Pattern formation involves many intrinsic mechanisms and principles concerning plasma,gas discharge,and nonlinear science.DBD pattern can be classified into glow and streamer patterns.Due to different discharge regimes,DBD pattern can be classified into glow and streamer patterns,and the formation mechanisms of the two kinds of patterns can also be different.This paper comparatively investigates the characteristics and influencing factors of the two kinds of patterns through experiments and numerical simulation,and explores the common mechanism controlling pattern formation.The main research includes three parts listed as follows:Firstly,the effects of surface charge,duty ratio and pulse width of square-wave voltage,driving frequency,amplitude of voltage,and additional electric/magnetic field on glow and streamer DBD patterns are researched in experiments.Through comparative analysis on the experimental results,the common mechanism of generation and development of spatial non-uniformity and of formation of patterns in both DBD regimes is concluded.It is found that,spatial dynamics,but not the process on dielectric surface,of discharge plays the leading role in the formation of DBD patterns.Secondly,filametary interaction and involved physics in both DBD regimes are comparatively researched through both experimental and simulation work.It is found that an electron-focusing effect by dynamics of space charge is maily responsible for glow filamentary interaction,which,in different conditions(variations of intensity,width,and distance of filamentary discharges),may lead to different dynamical behaviors such as attraction,merging,and repulsion.However,the deposition of surface charge should also play an important role in streamer filamentary interaction,which may change the breakdown locations and motional behaviors of streamer filaments by distorting local electric field and changing the location of maximum electron multiplication.Finally,the self-organized evolution processes of DBD patterns are investigated under different initial double fluctuations induced by space charge or voltage with variations of their intensities,widths,and distances by employing segmented electrodes.A radial delay characterastics of pattened discharge is observed,along with which the self-organization of streamer filaments is comparatively analyzed.The essence of self-organzation in the evolution of DBD patterns is the electron-focusing effect,which also dominantes the generation of streamer filaments.This surface process(or surface-charge effect)is indecisive,but also plays an important role in self-arrangement of streamer filaments and even richness and complexity of streamer patterns.