Experimental studies on striations in helium glow discharge

摘要

This letter reports the detailed observations and investigations of striations in the positive column region of helium glow discharges with a pin-to-plate copper electrode geometry in the pressure range 9-101 kPa. The striations are characterized by several plasma layers with alternate brightness and darkness. In this discharge, features such as negative glow, Faraday dark space, and striated positive column regions can be clearly observed. The evolution of a striation structure in the positive column region was found to be sensitive to gas pressure and electrode spacing. The striated discharge propagates in the form of an ionization wave with a velocity of 20.78 m/s and a frequency of 5.2kHz.