A coupled performance and thermal model for radio-frequency gridded ion thrusters*

Abstract

Abstract.Recently proposed space missions such as Darwin, eLISA and NGGM have encouraged the development of electric propulsion thrusters capable of operating in the micro-Newton (μN) thrust range. To meet these requirements, radio frequency (RF) gridded-ion thrusters need to be scaled down to a few centimeters in size. Due to the small size of these thrusters, it is important to accurately determine the thermal and performance parameters. To achieve this, a multi-physics performance model has been developed, composed of plasma discharge, 2D axisymmetric ion extraction, 3D electromagnetic and RF circuit models. The plasma discharge model itself is represented using 0D global, 2D axisymmetric and 3D molecular neutral gas, and Boltzmann electron transport sub-models. A 3D thermal model is introduced to determine the temperature distribution for various throttle points, using as inputs the plasma and electromagnetic field heating values obtained from the performance model. This also allows the validation of the performance model itself. Additionally, we analyze the effect the thruster's temperatures play on the plasma properties/performance and vice versa. The model is based on the RIT 3.5 thruster developed for the NGGM mission geometry and predicts the RIT 3.5 experimental data within approximately 10%.

Modeling the influence of an electric thruster’s ion beam on its global EMC

“…There are approaches to simulating the entire extraction system including the beam; very large computational requirements (computational clusters) are necessary because there is insufficient information about the actual beam. The current beam profile depends on the curvature of the grids and also on the plasma density distribution in the ionization vessel (Dobkevicius and Feili, 2016;Reeh et al, 2019). The model is based on empirical values.…”

Radio-Frequency Ion Thrusters—Power Measurement and Power Distribution Modeling

“…To have the electromagnetic model calculate the correct deposited power density within the plasma, a realistic representation of the plasma density distribution, which ultimately determines the distribution of conductivity, is modeled using heuristic proles introduced and veried in [27]. The distribution H follows a parabolic shape dened by…”

Лучистый Тепловой Поток От Возбужденных Атомов В Высокочастотном Ионном Двигателе

“…Неопределенностью параметров для расчетов q ex , повидимому, можно объяснить применение в существующих численных моделях [8,9] 0-мерного приближения для однородности по объему V 0 ряда параметров плазмы, в том числе и плотности q ex , т. е. принимается, что q ex = W ex /V 0 = const. Из этого допущения в моделях делается "…”