Iodine has the potential to be a mission-enabling propellant for electric propulsion; however, iodine as the working gas in a hollow cathode presents many challenges. Iodine propellant was compared with a typical propellant, xenon, in both cathode operation and plume properties. In this work, a low-current ($<5\mathrm{A}$) barium oxide hollow cathode was operated on xenon and iodine propellants. Its discharge current and voltage, and plume properties in the near-keeper region are reported for xenon and iodine with the cathode at similar operating conditions for each. The cathode operating on iodine required higher power for ignition and discharge maintenance compared with xenon, as evidenced by higher keeper and anode potentials. Plasma properties in the near-keeper region were measured using an emissive probe and single Langmuir probe. For both propellants, the plasma density, electron energy distribution function, electron temperature, select reaction rate coefficients, and time-resolved plasma potentials are reported. For both propellants, the cathode operated the same keeper (0.25 A) and discharge current (3.1 A), but the keeper and anode potentials were higher with iodine: 27 and 51 V for xenon, and 30 and 65 V for iodine, respectively. For both propellants, the electron distribution was best represented by a drifting Maxwellian, characterized by an electron temperature and drift energy. For xenon, the mean electron energy and electron temperature were 7.5 and 0.7 eV, with bulk drift energy of 6.6 eV. For iodine, the mean electron energy and electron temperature were 6.3 and 1.3 eV, with bulk energy of 4.2 eV. A literature review of relevant collisional processes and associated cross sections for an iodine plasma is also presented.

碘具有成为电动推进任务的推进剂的潜力。然而，碘作为空心阴极中的工作气体提出了许多挑战。在阴极运行和羽流特性方面，将碘推进剂与典型的推进剂氙进行了比较。在这项工作中，$<5\mathrm{一种}$氧化钡空心阴极在氙和碘推进剂上运行。据报道，氙和碘的放电电流和电压以及近保持区的羽流特性与阴极在相似的工作条件下均如此。与氙气相比，在碘上运行的阴极与氙气相比，其维护点火和放电所需的功率更高，这表现在较高的保持器和阳极电势上。使用发射探针和单个Langmuir探针测量近保持区的血浆特性。对于这两种推进剂，均报告了等离子体密度，电子能量分布函数，电子温度，选择的反应速率系数和时间分辨的等离子体电势。对于这两种推进剂，阴极使用相同的保持器（0.25 A）和放电电流（3.1 A），但是碘的保持器和阳极电位更高：氙分别为27 V和51 V，碘分别为30 V和65V。对于这两种推进剂，电子分布最好用漂移麦克斯韦（Maxwellian）表示，其特征在于电子温度和漂移能。对于氙，平均电子能量和电子温度分别为7.5和0.7 eV，体漂移能量为6.6 eV。对于碘，平均电子能和电子温度分别为6.3和1.3 eV，体能为4.2 eV。还介绍了有关碘血浆的相关碰撞过程和相关横截面的文献综述。以电子温度和漂移能为特征。对于氙，平均电子能量和电子温度分别为7.5和0.7 eV，整体漂移能量为6.6 eV。对于碘，平均电子能和电子温度分别为6.3和1.3 eV，体能为4.2 eV。还介绍了有关碘血浆的相关碰撞过程和相关横截面的文献综述。以电子温度和漂移能为特征。对于氙，平均电子能量和电子温度分别为7.5和0.7 eV，整体漂移能量为6.6 eV。对于碘，平均电子能和电子温度分别为6.3和1.3 eV，体能为4.2 eV。还介绍了有关碘血浆的相关碰撞过程和相关横截面的文献综述。