Evaluation of Ion Beam Behavior in 50 W Class RF Ion Thruster

Huong T T Nguyen,Jichul Shin,Hoai-Duc Vu,Linda L Vahala

doi:10.1155/2021/2847715

Huong T T Nguyen, Jichul Shin + Show 2 more

Open Access

https://doi.org/10.1155/2021/2847715

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Abstract

Phenomenological behavior of ion beam acceleration through the grid system in 50 W class RF ion thruster has been investigated using PIC simulation and evaluated by experimental test using Faraday probe. Beam trajectory for various grid voltages reveals that the metal engine cover of the ion thruster which is needed to seal RF coil around the discharge chamber affects the beam divergence angle. Simulation result shows that the divergence angle increases by 10.52% mainly because of the larger radial electric field in the presence of the metal engine cover. The divergence angle increases as the accelerator grid voltage increases. The current density distribution measured by the Faraday probe shows a bigger divergence angle with the engine cover installed. For the test cases with mass flow rates from 3 sccm to 4 sccm at the RF power of about 50 W, the current density distribution exhibits the 2nd peak at the radial position about 4 cm from the centerline.

Highlights

Electric propulsion is widely used in satellite propulsion system owing to the successive development of Hall thrusters and ion thrusters
Mass flow rate is set constant at 4 sccm, and the probe is placed at 10 cm away from the accelerator grid surface
PIC simulation result has shown that the radial electric field is increased by up to 19% when the metal engine cover is installed

Summary

Introduction

Electric propulsion is widely used in satellite propulsion system owing to the successive development of Hall thrusters and ion thrusters. In the design and development of ion thruster, the grid system must be designed and optimized for individual thrusters in that the divergence angle and morphology of the ion beam are important as it directly affects the specific impulse and thrust. It is reported in the previous experimental and theoretical research that the divergent characteristics of the ion beams produced by single and multiaperture accelerator systems are affected by geometric parameters of the grid and operating conditions [8,9,10,11,12]. This perveance does not account for the beam divergence outside the grid system where the charge distribution can be modified by the electric field formed outside the accelerator grid

PIC Simulation of the Ion Beam

Results and Discussion

55 W 50 W 45 W

Conclusions