A Study Of Ionization Stage Impact On Potential-trap Double Stage Hall Thrusters

Hall Effect Thruster (HET) is an electric propuls ion device that has beenengineering applied for about40years. It’s suitable for orbit-transfer, station-keeping or resistance compensation task of spacecraft with its characteristics ofhigh-specific and high-efficiency. As the improve requirements of spacecraftpropuls ion system, hall thruster develop to high-power and multi-mode model,so double stage hall thrusters(DSHET) are designed. By separating theionization and the acceleration process, the thruster can work in multi-mode,use different working substances, and have a low noises level. So this paperexperimenta l study on phys ical process impacted by ionization stage in adouble stage hall thruster based on potential-trap.This paper first gives the theory analysis of working principle of doublestage hall thrusters based on potential-trap. By combining the magnetic focustechnology of plasma plume and the potentia l-trap, the author design a newtype hall thruster MAG-70, which can be used as a prototype for experimentresearch. The thruster ’s ionization stage has a potential-trap structure and theacceleration stage base on magnetic focus technology. And also the papersummarizes the important problem in design, machining and experiment, suchas magnetic circuit design and structure check, and gives effective solutions.After that, the paper gives the experiment study on physical process inionization stage. By analyzing of the magnetic circuit coupling, this paper givesa effective solution scheme of decoupling, that makes independent magneticfield adjustment achieved in the two-stage. So the paper shows a experimentthat analys is ionization stage’s plasma parameters in variable electromagnetic field case using a langmuir probe, and get the influence trend. According to theresult of the experiment the author analyzes the mechanism of electromagneticfield influence on ionization stage working mode.Also the paper studies on the transport effect of plasma between the twostages, by using a double-side probe that can collect directional ion current inthe section of the anode. As the study shows, electromagnetic fie ld can stronglyaffect the directional current, comb ining with the measure of directional currentin plasma plume, gives a proportion that ionization process happens in the twostages, and also the ionization stage’s transport effect influence on ion currentof acceleration stage and utilization ratio of working substance.At last, this paper gives experimental work of discharge currentcharacteristics in the DSHET, and finds that the discharge current hasdistribution characteristics between the two-stages. Combining with theexperimenta l work of the third and the fourth chapter in this paper, givesqualitative expla ins of how electromagnetic fie ld influence on the dischargecurrent in ionization stage. At the same time, shows experimental work that canverify ionization stage’s inhibitory effect on low frequency oscillation, andanalysis this phenomenon from the preionization effects and the magnetic fie ldgradient angle.