Influence of anode temperature on ignition performance of the IRIT4-2D iodine-fueled radio frequency ion thruster

This paper reports the ignition performance of the iodine-fueled radio frequency (RF) ion thruster (IRIT) at different anode temperatures ($T_{\mathrm{a0}}$). The experimental results show that the anode temperature plays important role on the ignition process of the IRIT. There were two characteristic temperatures related to the anode: the minimum ignition temperature ($T_{\mathrm{i0}}$) and the stable ignition temperature ($T_{\mathrm{is}}$), which were much lower than the pipeline temperature and the storage tank temperature. At $T_{\mathrm{a0}}$<$T_{\mathrm{i0}},$ it failed to discharge. When $T_{\mathrm{i0}}$≤$T_{\mathrm{a0}}$<$T_{\mathrm{is}},$ it was ignited with dramatical oscillations. At $T_{\mathrm{a0}}$≥$T_{\mathrm{is}},$ the discharge was stable in a large anode temperature range. The analysis showed that the different discharge phenomena at different anode temperatures were attributed to the change of iodine flow rate during the process of the iodine deposition-clogging and sublimation-clearing inside the thruster. The research helps improve the preheating design of the iodine-fueled electric thruster.