Breakdown mode and parameter space of micro-discharge sustained by thermionic emission

Abstract

Gas breakdown driven by thermionic emission(TE) in a microgap to produce low
temperature plasma was studied by one-dimensional implicit Particle-in-cell/Monte
Carlo collision(PIC/MCC) model. The influence of background gas pressure, external
driving voltage, cathode temperature and discharge gap on argon glow micro-discharge
in the parallel plate was simulated. Different parameters and conditions have different
effects on the gas breakdown at small size. The discharge gap of 100’s μm has little
influence on gas breakdown and only changes the plasma distribution. As the applied
voltage increases, the gas changes from non-breakdown mode to breakdown mode, and
gas breakdown is more sensitive to the applied voltage than the gas pressure at low
voltages. In all breakdown modes, the gas pressure hardly changes the plasma evolution
characteristics. At appropriate cathode temperatures, the density of electrons and ions
increases rapidly, forming a stable sheath and the equivalent resistance of the discharge
gap becomes smaller as the temperature rises, the plasma is in abnormal glow discharge.