Study Of The Striations In Radio Frequency Capacitively Coupled Discharge In Ar

Striation in gas discharge is one of the non-linear phenomena.The study of the striation formation in radio frequency(RF)discharge is helpful to understand the physical characteristics and improve the application of RF discharge in industry and scientific research.In this thesis,the striations in RF capacitively coupled discharge are studied experimentally.Using a RF power source of 13.56 MHz,layered striations and ball-shaped striations were obtained in argon.The experimental results show that layered striations will be obtained at lower pressure and smaller discharge chamber,while ball-shaped striations will be obtained at higher pressure and larger discharge chamber.The time-integrated images show that the double-layered striations in a RF discharge are stable.That is because the varying electric field under a RF cycle driving the striations to move slightly.The experimental results also show that ball-shaped striations can be formed near the power electrode and the ground electrode respectively,and the striations will fuse and finally disappear while they are moving away from the electrodes.The striations formed in hollow power electrode show that high electron density near the electrode is a key factor of striation generation.With higher power applied,self-organized discharge channels with striations will be formed near the electrode surface.In this thesis,the ball-shaped and layered striations are founded in RF capacitively coupled argon plasma.Till now,this is the first time to obtain striations and self-organized channels in RF discharge.It will have great influence on the subsequent study of striations in RF discharge.