碘工质射频离子微推力器碘等离子体放电及推进机理研究

At present, electric propulsion technology using Xeon as the propellant or immersed electrodes may have problems such as heavy weight, high cost, and limited life. The iodine radio-frequency ion thrusters(IRITS) have the advantages of light weight, low cost, and long life due to the use of solid-state propellant and inductively coupled discharge. In the future, IRITS may improve greatly the on-orbit life and control capabilities of microsatellites, and hopefully become a main direction of the next generation of electric propulsion technology. According to current literature research, there is currently a lack of research on the iodine plasma and beam ion properties in the discharge chamber of an iodine RF ion thruster, making it difficult to further optimize the thruster. Therefore, in this project, using an iodine radio-frequency ion thruster as the experimental model, the variation law of iodine plasma parameters in the discharge chamber and beam ion parameters with the thruster macroscopic parameter will be studied to establish the mutual coupling relationship among the external macroscopic parameters, plasma parameters and propulsion performance of the thruster, by which the mechanism of iodine plasma discharge will be analyzed ,and further the thrust generation mechanism of IRITS will be revealed. Finally, based on the experimental model and experimental results, a simulation model will be established. As a result, a complete system from experiment to simulation will be established to provide theoretical and experimental support for the further optimization of IRITS.

目前以氙为工质或者采用浸入式电极的电推进技术可能存在干重大、成本高以及寿命受限等问题，碘工质射频离子推力器因采用固态工质和电感耦合放电的形式而具有质量轻、成本低和寿命长的优势，未来可能使微小卫星在轨寿命和调控能力实现质的提升，有希望成为下一代电推进技术发展的主要方向。根据现有文献调研，目前国际上对碘工质射频离子推力器放电腔内碘等离子体和束流离子特性缺乏相关研究，因而难以对推力器进行更进一步的优化。因此，本课题拟以碘工质射频离子推力器为实验模型，研究放电腔内碘等离子体参数和离子束流特性随推力器外部宏观参数的变化规律，建立推力器外部宏观参量、等离子体参数和推进性能之间的相互耦合关系，进一步分析碘等离子体放电机制，揭示碘工质射频离子推力器推力产生机理；并根据实验模型及实验结果建立和不断完善仿真模型，建立从实验到仿真的一整套系统，为实验室碘工质射频离子推力器的进一步优化提供理论和实验基础。

目前以氙为工质或者采用浸入式电极的电推进技术存在干重大、成本高以及寿命受限等问题，碘工质射频离子推力器由于采用固态工质和非浸入式电极的方式而具有质量轻、成本低和寿命长的优势，未来可能使微小卫星在轨寿命和调控能力实现质的提升，有希望成为下一代电推进技术发展的主要方向。根据现有文献调研，目前国际上对碘工质射频离子推力器放电腔内碘等离子体和束流离子特性缺乏相关研究，因而难以对推力器进行更进一步的优化。为研究碘工质射频离子推力器放电及机理，研究了碘固态工质升华、低气压放电及离子束流产生机理，理论分析了放电腔内等离子体参数，并对放电腔电场和磁场分别进行了仿真，建立一套碘工质射频离子推进系统，包含固态碘工质流量控制系统、功率产生及控制系统、推力器以及中和器。研究了推力器外部宏观参量包含工质流量、射频功率和屏栅电源与推进性能之间的关系,试验表明在相同条件下碘工质性能与氙可比较；以RIT4射频离子推力器为研究对象，研究了放电腔内等离子体参数与射频功率以及工质流量之间的关系，结果表明，随着射频功率的增加，放电腔内等离子体密度增加，在35W时为1011cm3；研究了离子束流电流密度分布以及束流发散角，通过改变推力器电源参数，研究了1.5-3mN推力范围内，沿羽流径向方向的电流密度分布，结果表明，羽流发散半角小于15°。..