Characterization of inductively coupled RF plasma source operating with molecular gases for electric propulsion

Inductively coupled radio-frequency (RF-ICP) plasma sources are widely used in semiconductor processing, mass spectrometry, nanomaterial synthesis, and also in space propulsion, where they operate across pressures from mTorr to atmospheric and power levels from tens of watts to tens of kilowatts. RF-ICPs offer an electrode-free, magnetic-field-free design that is simpler and lighter than helicon or electron-cyclotron-resonance sources, while advanced configurations with ferrite cores can achieve competitive ionization efficiency. This work develops and characterizes a low-pressure (≤10 mTorr), low-power (up to 250 W) RF-ICP source to maximize ionization of molecular gases with potential application to space propulsion such as plasma thrusters and cathodes with molecular propellant.