Performance characterization of the micro-Cathode Arc Thruster and propulsion system for space applications

Abstract

This paper describes a further development and characterization of vacuum arc thruster with external magnetic field. The velocity of ions moving from the micro-Cathode Arc Thrusters (µCAT) cathode spots was measured using a set of grid probes along the path of the plasma plume expansion. The goal was to get the ion drift velocity and determine how much, if any, change of ion drift velocity occurs in the expanded plasma propagation path. It was found the ion drift velocity was increased when magnetic field increased (from 0 up to 200mT). The average ion velocity (cathode material is Ti) increases by factor of 2-3 up to about (3-4) × 10 4 m s −1 with magnetic field strength 200mT applied. Rotation of cathode spot as a result of an applied magnetic field is demonstrated by using Langmuir probes inserted inside the source channel azimuthally. Ion current distribution outside the thruster channel was measured using a set of special assemble of concentric circles plan probe alone the plasma propagation path. It is shown that plasma generated at the cathode spot is guided along the magnetic field line.

Numerical simulation of the plasma acceleration process in a magnetically enhanced micro-cathode vacuum arc thruster

“…It is also noted that ions follow the electron movement and form a hollow plasma plume shape at the downstream of the computation domain. This is also demonstrated in the experiments in references [23,39].…”

“…As shown in figure 11(b), at the downstream of the computing domain, as the magnetized electron channel deviates from the axis, the ion movement also gradually deviates from the axis. Compared with the corresponding cases of Case 1 shown in figure 6, the hollowing of the plume is more obvious [39].…”

Optimization of discharge triggering in micro-cathode vacuum arc thruster for CubeSats

“…Schein et al [16] demonstrated that optimization of the electrode configuration is an important factor affecting thruster lifetime in both planar and tubular geometries; the lifetimes achieved are 10 6 pulses for the so-called bi-level planar thruster, and more than four million pulses for a tubular configuration with a thin-walled tube-like cathode and a spring feeding system. Zhuang et al [17] designed a μCAT with a tube-like configuration of anode and cathode separated by a dielectric ring with a conductive layer. However, such a thruster, although providing a relatively very long lifetime (up to 10 8 pulses) [17], had a very significant drawback: low thrust efficiency-since the majority of produced ions attached to the inner walls without producing thrust as a consequence of the tube-like geometry [18].…”

Plasmonic Force Propulsion for Small Spacecraft

“…However, the CAT is currently only estimated to have a lifetime of 10 8 pulses, meaning with an impulse bit of 2 Ns, it will only be able to provide 100 m/s of ΔV to a 2 kg cubeSat. [17] With a switching time of 20 ms the CAT can provide good pointing and positioning accuracy of 1× 10 −4 deg and 6× 10 −4 m. As a result of the relatively high thrust produced by the CAT and larger switching time it is not as well suited for missions which require high accuracy pointing and proximity control as PFP thrusters.…”