Modeling of DC Discharges in Argon at Low Pressures
1Vapor Technologies, Inc., Longmont, CO, USA
The glow discharges in argon at pressures of 1 to 20 mTorr are modeling using COMSOL Plasma Module. DC glow discharge with secondary electron emission is compared to low pressure arc with thermionic emission. Boundary conditions on dielectric discharge tube walls are compared to that of metallic discharge tube walls. Modeling revealed that electron emission mechanisms as well as boundary conditions on discharge tube walls are strongly influencing both plasma distributions across discharge tube and electrical characteristics of the discharges. The results show that the I-V characteristics of thermionic discharge have a negative differential resistance typical to arc discharges while in self-sustain DC discharges the I-V characteristics have a positive differential resistance typical for glow discharges with secondary electron emission.