Fluid modeling of inductively coupled iodine plasma for electric propulsion conditions

Iodine is being studied as an alternative propellant for electric propulsion application as it has numerous advantages over commonly used xenon gas. In spite of numerous experimental studies for the conditions typical for electric propulsion, there are very few computational modeling studies of iodine plasmas: all with reduced geometric representations in zero or one dimension. In the present paper, we use self-consistent two-dimensional fluid model coupled with Maxwell's equations to analyze the inductively coupled plasma generated in low-pressure iodine. We compare the plasma parameters for two values of the background pressure: 1.0 and 2.5 Pa. We find that ∼99% of the molecular iodine is converted into atomic iodine. As a result, plasma consists of electrons, ions I+, and a significant number of negative ions I−. The density of molecular ions I2+ is much smaller than the density of I+. We analyze the transport of these species for two pressures and show that there are different regimes of plasma diffusion realized for the conditions of our studies. We also study how the discharge power influences the plasma parameters such as the electron and ion densities and the electron temperature.