Simulation of charged and excited particle transport in the low-current discharge in argon-mercury mixture

Abstract

Simulation of the electron, ion and metastable excited atom transport in the argon-mercury mixture low-current discharge is fulfilled. Distributions of the particle densities along the discharge gap under different mixture temperatures are obtained and it is demonstrated that the principal mechanism of mercury ion generation is the Penning ionization of mercury atoms by argon metastables, which contribution grows sharply with the mixture temperature due to mercury density increase. Calculations show that the mercury and argon ion flow densities near the cathode are of the same order already under the relative mercury content of about 10−4 corresponding at the argon pressure 103 Pa to the mixture temperature 30 C. Therefore, at the room temperature the electrodes of mercury illuminating lamps at the stage of their ignition are sputtered predominantly by mercury ions.