Jet extraction modes of inertial electrostatic confinement devices for electric propulsion applications

The Inertial Electrostatic Confinement (IEC) method is a plasma confinement principle with different operation modes. The work presented investigates the jet mode, which occurs with a jet extraction relevant for space propulsion applications. Two different jet modes were observed, the tight jet mode and the spray jet mode. Depending on propellant, discharge pressure and power these modes occur at different operation conditions and characteristics. Emission spectroscopic investigations show a different plasma species composition of confinement and extraction plasma and the transition between those modes has been examined with a high-speed camera. Finally, the applicability of IEC plasma sources for space propulsion systems is discussed with respect to the experimental results.