Speaker
Description
Pulsed plasma thrusters (PPTs) have vast potential for application in small satellites. Capillary discharge, which produces high density and relative low temperature plasma, has a great interest in space propulsion devices. Based on the capillary discharge, PPTs make full use of electrothermal acceleration mechanism to promote the overall efficiency in low energy level.
In this paper, a capillary discharge based pulsed plasma thruster has been designed, the main discharge circuit was compact, and the circuit inductance was low. With the change of the main capacitor capacitance and charged voltage, the current rising rate could be adjusted from 3A/ns to 20A/ns. Under the given dimensions of discharge cavity, the effect of different current rising rates on the ablation and plasma bulk velocity was studied.
With an electronic balance, the ablated mass per 1000 shots was measured. As the result showed, the ablated mass increased with increasing the current rising rate. It has been proved that the current rising rate has an effect on the ablation and ionization of propellant, affecting the relative content of products. This effect was studied with a spectrometer. A reduction of the current rising rate decreased the emission spectrum intensity of plasma with a similar composition.
With the PMT array, the plasma bulk velocity was measured based on the time-flight method. Result showed that increasing the current rising rate would accelerate the plasma bulk to a higher velocity. Meanwhile, the light-emission intensity showed the same tendency as the plasma bulk velocity.
