Abstract: For the purpose to study the problems of plasma beam focusing，like bad spreading state of plasma beam，when krypton is used to replace xenon as the propellant of the electric propulsion，regarding magnetic field parameters，discharge voltage and propellant flow of anode as a single variable respectively，three experimental researches have been carried out to investigate their effects on beam focusing of the thruster. Experiments was made by the HET - P70 hall thruster to study the effects of magnetic field configuration on krypton thruster performance by changing the parameters of magnetic field，finally finding that the appropriate field configuration can form magnetic focusing state，as case 3 of the first experiment，it can make the plume divergence angle to be 11.5°. And the discharge voltage is 400V，while the propellant flow of anode is 3mg/s at the moment. In addition，the influencing mechanism of propellant flow of anode and discharge voltage on krypton plasma beam focusing was studied through the second experiment and third experiment，finding the change of two parameters mainly changed the location of neutral gas ionization area，then affecting the state of the plasma beam focusing. When ionization area moved 9% of setting condition outward，the half angle of the plume divergence increased about 12°. Thus the magnetic field configuration and gas ionization position are the important factors that affect the krypton plasma beam focusing. During the optimization design of krypton hall thruster，they should be given priority.

Key words: Krypton；Hall thruster；Beam focusing；Magnetic focusing

摘要： 以研究氪气替代氙气作为霍尔推力器工质时，等离子体束发散程度大等束聚焦特性问题为目的，通过以霍尔推力器磁场参数、放电电压和阳极工质流量分别作为单一变量进行实验研究，考察其对推力器等离子体束聚焦影响情况。使用HET-P70霍尔推力器进行相关实验，通过改变磁场参数来研究磁场位形对氪气工质推力器性能的影响，最终发现合适磁场位形形成的磁聚焦状态，即实验一中的工况3，可以使羽流发散角达到11.5°，此时推力器放电电压在400V，阳极工质流量3mg/s。另外，通过实验二和实验三，考察阳极工质流量和放电电压对氪等离子体束聚焦的影响机理，发现两个放电参数的变化主要改变了中性气体主电离区位置，进而影响等离子体束聚焦状态。电离位置在设定工况下外移9%，会使得羽流发散半角增大约12°。所以，磁场位形和中性气体的电离位置是影响氪等离子体束聚焦的重要因素，在对氪气霍尔推力器进行设计优化时应予重点考虑。

关键词: 氪气；霍尔推力器；束聚焦；磁聚焦