Formation of white-eye pattern with microdischarge in an air dielectric   barrier discharge system
  We report on the first observation of white-eye pattern in an air dielectric barrier discharge. The patterned discharges undergo a development as following: random spots - quasihexagonal pattern - hexagonal pattern (type I) - hexagonal pattern (type II) - white-eye pattern - chaos as the voltage is increased. The spatiotemporal characteristics of patterned discharges are investigated by using an optical method. Results show that the two discharge modes, uniform mode and filamentary mode, are actually two different spatial presentations of the same origin: the microdischarge. From the viewpoint of pattern dynamics, the white-eye pattern results from a 3-wave resonance interaction. 
Yafeng He, Lifang Dong, Weili Liu, Hongfang Wang, Zengchao Zhao, and   Weili Fan
physics.plasm-ph nlin.PS