Comparison of 1D PIC simulations with experimental electron measurements in an iodine plasma for electric propulsion.

The electric propulsion industry is facing a shortage of its favored propellant, xenon. Thanks to their chemical inertness, stable noble gases are easier to model. As the heaviest and easiest to ionize, xenon offers the best compromise of ease of use and power efficiency. While some actors have chosen to make a concession on efficiency by using lighter gases, especially in constellations, other elements are considered.

Iodine, with a mass close to that of xenon and a lower ionization threshold, is a strong contender and may offer similar performances. However, the modeling and simulation of such plasma require additional attention due to its molecular and electronegative natures.

In this work, we aim to validate the implementation of iodine chemistry in a 1D-3V PIC code by comparing electron parameters with Langmuir probe measurement in an iodine ICP discharge. We improved the Monte Carlo collision routine to include electronic collisions with molecular iodine and added binary collisions to model negative ion losses in the volume. To simulate the finite volume of the experimental device, we model the Bohm flux in the unsimulated directions with a 2D h factor model taking electronegativity into account.