射频自偏压效应离子推力器束流特性实验研究

Experimental Study on Ion Beam Characteristics of Ion Thruster Using RF Self-Bias Effect

关键词:  自中和  射频自偏压效应  离子推力器  束流特性  实验研究

Key words:  Self-neutralization  RF self-bias effect  Ion thruster  Ion beam characteristics  Experimental study

摘要:

为了获得不同推力器工况对射频自偏压效应离子推力器的自偏压幅值和束流特性的影响，本文通过地面实验研究了栅极射频功率、线圈放电功率、工质种类对自偏压幅值和羽流区等离子体参数的影响，同时对直流栅极工况和射频栅极工况下的束流特性进行了对比。研究结果表明：栅极射频功率的增大会提高自偏压幅值并提升束流强度，但在较高栅极射频功率下，栅极下游区域将发生自持放电并形成等离子体；放电腔内放电模式转换会通过改变等离子体阻抗的方式大幅影响栅极直流自偏压幅值和栅极电压的射频分量，进而影响羽流区等离子体参数；与直流栅极工况相比，射频栅极能同时引出并加速离子和电子，并在栅极下游实现自中和，且在Ar，Kr，Xe三种工质下均具有自中和能力。

Abstract:

In order to obtain the influences of thruster’s operating condition on the self-bias amplitude and ion beam characteristics of ion thruster using RF self-bias effect， the effects of grid’s RF power， antenna’s discharge power and propellant on the self-bias amplitude and plasma parameters in the plume region were studied， and the ion beam characteristics under DC and RF modes were compared through ground experiments in this paper. The results show that the increase of grid’s RF power helps to enlarge the self-bias amplitude and improve the intensity of ion beam， but a higher power would cause self-sustained discharge and form plasma in the downstream region of the grids. The change of discharge mode in the chamber greatly affects the self-bias and RF amplitude by changing plasma’s impedance， and then influences the plasma parameters in the plume region. Compared with DC mode， thruster working under RF mode can simultaneously extract and accelerate ions and electrons， and realize self-neutralization downstream the grids. Self-neutralization can be achieved by using Ar， Kr and Xe as propellant.