霍尔推力器阳极加热机制及设计优化

Heating Mechanism and Thermal Design Optimizationof Anode in a Hall Thruster

关键词:  阳极  加热机制  低温等离子体  霍尔推力器

Key words:  Anode  Heating mechanism  Low temperature plasma  Hall thruster

摘要:

阳极的过热不仅降低霍尔推力器的放电稳定性和推力效率，同时也是推力器的一种失效原因，直接引起推力器放电电流、功率异常增加导致关机故障。为在设计阶段解决阳极过热失效问题，本文通过理论分析建立了阳极热过程模型，分析得到阳极鞘层的形成是影响阳极热功率的核心过程，而阳极电流密度和磁感应强度是影响鞘层特性的关键参数。研究结果表明，阳极鞘层电势差随阳极电流密度的提高而增大，在典型近阳极区等离子体参数下，阳极电流密度小于600A/m2时，阳极负鞘层形成；而阳极热功率随着近阳极区磁感应强度的增加而升高，将阳极位置设计在零磁场区是最有利于降低阳极热功率的设计。

Abstract:

The anode overheating not only causes the reduction of the discharge stability and thrust efficiency，but also can be treated as a kind of failure mode of Hall thrusters，which directly causes the discharge current and power consumption abnormally increased，even immediately shut down. Therefore，in order to solve the anode overheating problem，the anode thermal process theoretical model is established. The model analysis results indicate that the anode sheath forming process is core process effecting the thermal power of the anode，and the anode current density and magnetic field strength are the key factors in the sheath forming process.The research results show that the anode sheath potential drop increases with the anode current density. In the typical plasma parameters near the anode region，the negative anode sheath will form if the anode current density is less than 600A/m2. Furthermore，the anode thermal power also increases with the magnetic field strength near the anode region，therefore，keeping the anode position in the zero magnetic field region will be the optimized design to reduce the thermal power of the anode.