Observations of Saffman-Taylor-like instability induced by atmospheric dielectric barrier discharge
1Department of Physics, National Chung Cheng University, ChiaYi, Taiwan
* presenting author:Hong-Yu Chu, email:phyhyc@ccu.edu.tw
We report the unstable phenomena of the plasma-liquid interface with different curvature in a Hele-Shaw cell. Dielectric barrier discharge is produced in the cell at atmospheric pressure which is partially filled with silicone oil. We show that the Saffman-Taylor-like instability is observed on the bubble-type, channel-type, and drop-type interfaces. The plasma/liquid/gas interactions are discussed. The Schlieren observation on the boundary of the oil drop reveals that there is a vapor layer around the oil drop and the particle image velocimetry shows the liquid flow inside the drop. We propose that the thermal Marangoni effect induced by the plasma heating is responsible for the periodic fluctuation and finger branching in the plasma-liquid interaction process. The fluctuation of the interface is shown consistently with the Saffman-Taylor instability modified by the temperature-dependent velocity and surface tension.

Keywords: Saffman-Taylor instability, dielectric barrier discharge, plasma-liquid interaction