Analysis of the effect of scandium halide on energy and current transfer in unbalanced plasma layers near the cathode surface in arc discharge

Halide addition to xenon plasma enhances performance in electric discharge systems and high-intensity light sources, making it a practical strategy for various applications.This study examines the impact of adding scandium halide ScI to xenon plasma, using two concentrations (Sc 0.1% and 5%) and a 0.1% iodine content.The investigation was conducted under two discharge voltages to assess changes in cathode-plasma interaction, energy transport mechanisms, and current behavior.The research focuses on two aspects: energy transport to the cathode, including total energy flux, ion energy, fast electron energy, and thermionic emission losses, and the behavior of various current densities at the cathode surface, including changes in cathode sheath voltage and effective work function.The study found that at a low concentration of Sc 0.1%, the discharge characteristics of xenon remain similar to pure xenon, indicating minimal disruption to the plasma environment.However, at Sc 5%, energy transfer efficiency improved significantly, with a 30% increase in total energy flux due to enhanced ionization, reduced thermionic energy loss, and improved energy transport.The analysis of current density showed that components increase with cathode surface temperature, with thermionic electron emission becoming the dominant current mechanism at higher temperatures.This transition occurred more rapidly at 25 V and with higher ScI concentration.The intersection point between j and total current shifted to lower temperatures.The cathode sheath voltage decreased with improved electron emission, indicating a shift towards a space-charge limited regime.A and floating potential exhibited temperature-dependent behavior.The study demonstrates that the addition of scandium iodide at a Sc 5% concentration, even with a low iodine content, significantly enhances plasma performance by increasing energy flux, enhancing current transfer efficiency, and reducing cathode energy losses.