The Influence of Thallium Halide on Improving Arc Discharge Properties under Atmospheric Pressure

Abstract

In this work, a comprehensive numerical analysis was conducted to investigate the effect of cathode surface temperature (T_w) on several key plasma parameters. These include the electron energy flux density(q_e), the emitted electron energy flux density (q_em​), the total plasma current density (j), and its individual components: electron current density (j_e​), ion current density (j_i ), and thermionically emitted electron current density (j_em). The relationship between the electron temperature in the plasma (T_e) ​and the cathode surface temperature (T_w​) was also examined, as this interaction plays a crucial role in defining surface reactions and overall plasma behavior. The simulations were carried out using pure xenon and a xenon–thallium gas mixture at different thallium concentrations (0.001, 0.01, and 0.1 mol.) under two applied voltages: 20 V and 40 V. Results indicated that the optimal performance was achieved with pure xenon at an applied voltage of 20 V. This is attributed to the higher ionization energy of xenon, which leads to greater electron energy and current densities compared to the Xe-Tl mixtures. Additionally, plasma operation at the lower voltage of 20 V was found to be more efficient than at 40 V, as it promotes greater stability in both electron energy and current density. This, in turn, enhances the overall plasma performance and energy efficiency of the system. These findings underscore the importance of carefully selecting the gas composition, applied voltage, and cathode temperature to optimize the discharge process, particularly in applications requiring stable plasma operation and high efficiency output, such as advanced lighting systems.