Electron Cyclotron Resonance Thrusters

A close-up of an ECR thruster with a magnetic nozzle.

project personnel
Benjamin Wachs, Sal Baldinucci

principal investigator
Benjamin Jorns

project sponsors

associated facilities
ECR Thruster Chamber

Electron Cyclotron Resonance (ECR) is one of several methods for ionizing and heating a plasma using electromagnetic (EM) waves. In a typical EM wave driven thruster, gas is ionized and heated by an EM wave, and this plasma is then ejected from the source through a magnetic nozzle, producing thrust. Wave driven thrusters have the potential to eliminate plasma contacting electrodes, which are subject to erosion and failure in typical electrostatic thruster designs. Furthermore, this type of thruster topology can substantially simplify overall thruster design, with only a single power supply necessary for operation.

However, to date, electromagnetic wave driven thrusters have not been able to match the performance and efficiency of traditional electric propulsion devices such as hall effect thrusters and ion thrusters. Most EM driven thrusters have utilized inductively coupled or helicon wave heating, which has produced efficiencies typically under 10%. Recent studies have shown that ECR heating has the potential to greatly improve these numbers, however, the physics is not well understood.

The goal of this project is to investigate ECR heating in magnetic nozzles, and to develop scaling laws for these thrusters. In particular, this research aims to determine if this type of thruster is viable for low power (sub kW) propulsion systems, which are increasingly important in new satellite designs. A prototype ECR thruster based on previous experiments has been constructed and tested at PEPL. Future work will focus on understanding and improving device efficiency through changes in wave coupling, thruster geometry, and applied power.


Selected Publications

  • Observation of Low Frequency Plasma Oscillations in the Plume of a Partially Magnetized Magnetic Nozzle

    Hepner, S.T., Wachs, B.N., Collard, T.A., and Jorns, B.A.

    54th AIAA/SAE/ASEE Joint Propulsion Conference, Cincinnati, OH, AIAA-2018-4730, July 9-11, 2018

  • Effect of Background Pressure on Ion Dynamics in an Electron Cyclotron Resonance Thruster

    Wachs, B. and Jorns, B.

    54th AIAA/SAE/ASEE Joint Propulsion Conference, Cincinnati, OH, AIAA-2018-4585, July 9-11, 2018

  • Technique for Two-Frequency Optimization of an ECR Magnetic Nozzle Thruster

    Wachs, B., and Jorns, B.

    36th International Electric Propulsion Conference, Vienna, Austria, IEPC-2019-219, 2019

  • Background pressure effects on ion dynamics in a low-power magnetic nozzle thruster

    Benjamin Wachs, Benjamin Jorns

    Plasma Sources Science and Technology, Vol. 29 No. 4, 10 February 2020

  • Wave-Driven Non-Classical Electron Transport in a Low Temperature Magnetically Expanding Plasma

    Hepner, Shadrach; Wachs, Benjamin; Jorns, Benjamin

    University of Michigan,, July 1, 2020

  • The role of low frequency drift waves in driving non-classical transport in magnetic nozzles

    Shadrach T. Hepner and Benjamin Jorns

    VIRTUAL,, August 17, 2020

  • Anomalous electron thermal conductivity in a magnetic nozzle

    Shadrach Hepner and Benjamin A. Jorns

    AIAA Propulsion and Energy 2021 Forum,, August 2021

  • Optimization of an ECR thruster using single, two-frequency, and pulsed waveforms

    Benjamin N. Wachs and Benjamin A. Jorns

    AIAA Propulsion and Energy 2021 Forum,, August 2021

  • Impact of Facility Electrical Boundary Conditions on the Performance of an Electron Cyclotron Resonance Magnetic Nozzle Thruster

    Salvatore S. Baldinucci, Sophia Bergmann, Jack A. Hondagneu, Benjamin Wachs, and Benjamin A. Jorns

    IEPC 2022,, June 2022

  • Sub-Millinewton Thrust Stand and Wireless Power Coupler for Microwave Powered Small Satellite Thrusters

    Benjamin N. Wachs and Benjamin A. Jorns

    Review of Scientific Instruments,, August 11, 2022