"The entire assembly is housed inside a tailored magnetic field called the “magnetic nozzle”. When an RF signal is applied to the antenna, the near-field patter

"The entire assembly is housed inside a tailored magnetic field called the “magnetic nozzle”. When an RF signal is applied to the antenna, the near-field pattern acts to ionize the propellant in the liner, and subsequently heat the plasma via stochastic electron-RF interactions [9, 10]. These interactions drive electrons out of the exit of the plasma liner. To maintain steady state charge balance, ions are accelerated by this momentary charge imbalance out of the liner, generating thrust. " Essentially, instead of using an electric field generated by a anode/cathode grid to pull the ions out of the thruster, they are using the RF to generate free electrons which generate an electric field and pull the ions out of the container.