电弧加热发动机喷出等离子体静电单探针测量

Single langmuir probe measurement in the exit plasma of an arcjet thruster

关键词:  电弧加热发动机  静电单探针  等离子体诊断

Key words:  Arcjet thruster  Single langmuir probe  Diagnostics of plasma

摘要:

应用静电单探针测量了kW级电弧加热发动机喷出等离子体参数分布。发动机以氮气为推进剂,测量范围为距离发动机喷口1.25~15cm,实验中真空舱压力为3~5Pa。实验获得了电子温度和电子数密度沿不同轴向位置和径向位置的变化规律,电子温度为0.4~0.8eV,电子数密度为1.2×10¹⁷~1.25×10¹⁸m-3。对比研究发现,N₂为推进剂产生的等离子体的电子温度和电子数密度均大于N₂-H₂为推进剂的情况,但前者发散角较小。

Abstract:

The parameters of ejected plasma in the range of 1.25~15cm to the exit of 1kW class arcjet with nitrogen as propellant were measured with a single langmuir probe. The pressure in the vacuum chamber was 3~5 Pa. The changes of electron temperature(0.4~0.8eV) and number density(ranging from 1.2×10¹⁷ to 1.25×10¹⁸m-3) along the axial and radial direction were obtained. The results showed that both the electron temperature and number density of ejected plasma with nitrogen as propellant were higher than those with N₂-H₂ as propellant, while the divergence angle was smaller.