Waveguide ECR thruster prototype could lead to significant changes in space propulsion
Waveguide ECR thruster prototype could lead to significant changes in space propulsion lead image
Satellite electric propulsion systems predominantly depend on Hall and Ion thruster technologies. The limited lifetime of hollow cathodes and grids, high-purity xenon needed for the cathodes, and system-level complexities remain major drawbacks in the continued use of these conventional thrusters.
Electron Cyclotron Resonance thrusters, or ECRTs, are expected to eventually overcome these challenges. Microwave power and electron cyclotron resonance heat up electrons in the plasma. Their thermal energy is converted to ion acceleration inside a magnetic nozzle. The resulting magnetic field delimits the expansion/acceleration region. However, the sub-category of electrodeless waveguide ECRTs possesses lower thrust efficiency and specific impulse than their electrode-bearing coaxial counterparts.
Inchingolo et al. developed a prototype to investigate the mechanisms behind waveguide ECRTs, circumvent their limitations, and optimize their operation.
“The ECRT presented here represents a breadboard prototype useful to study a variety of phenomena, including magnetic nozzles, plasma-wave, and plasma-wall interactions,” said author Marco Inchingolo. “Having a clear understanding of these is of central importance for making this kind of thruster suitable for space exploration.”
Focusing on thruster design and analysis of the plasma plume, the researchers inserted electrostatic probes into the plasma beam, enabling characterization of the plume in different configurations of power, mass flow rate, and magnetic nozzle shape. The results were also used to indirectly estimate performance metrics.
“This work identifies some of the mechanisms which are believed to drive the lower performance when compared with coaxial ECR thrusters,” said Inchingolo. “These must be targeted to make the device a viable thruster alternative for space applications.”
Source: “Plume characterization of a waveguide ECR thruster,” by M.R. Inchingolo, M. Merino, and J. Navarro-Cavallé, Journal of Applied Physics (2023). The article can be accessed at https://doi.org/10.1063/5.0138780 .
