A neutralizer suitable for use in an ion engine comprises a halogen gas source and an electrode tube comprising an inlet opening connected to the halogen gas source for supplying a halogen gas provided by the halogen gas source into the electrode tube, a discharge space for generating a plasma from the halogen gas supplied into the electrode tube, and an outlet opening for discharging the plasma generated in the discharge space and free electrons from the electrode tube. An electron emitter is arranged in the discharge space of the electrode tube, which is at least partially made of tungsten, a tungsten alloy or a tungsten composite material containing at least one of iridium, rhenium, ruthenium, rhodium and osmium.

A pulsed metal plasma thruster (MPT) cube has a plurality of thrusters, each having a first cathode electrode and a trigger electrode separated from the first electrode by an insulator sufficient to support an initiation plasma, and a porous anode electrode positioned a separation distance from the face of all of the cathode electrodes. The cathode electrode can be either the inner electrode or the outer electrode. A power supply delivers a high voltage pulse to the trigger electrode with respect to the cathode electrode sufficient to initiate a plasma on the surface of the insulator. The plasma transfers between the anode electrode and cathode electrode of selected thrusters, thereby generating a pulse of thrust.

A hollow cathode apparatus includes an outer tubular dielectric barrier circumferentially surrounding an outer tubular surface of the cathode tube, the outer tubular dielectric barrier being composed of a barrier material which is electrically non-conductive. Also disclosed is a system comprising the hollow cathode apparatus, an anode which is spaced from the output end of the tubular cathode, and electrical circuitry connected between the cathode tube and the anode for connection to a source of electrical power for providing an electrical potential between the cathode and anode to cause an electric current to pass from the emitter into the input gas to form a plasma which is then output through the output end of the cathode tube to form a plasma plume. The electrical circuitry comprises: a first power supply for connecting the cathode and the cathode electrode to a first source of DC power in an ignition power mode, wherein the first power supply comprises a current control device which is adapted to control the current between the cathode and the cathode electrode, wherein the current control device is arranged to function as an anti-surge current stabiliser; and a second power supply for connecting the anode and the cathode to a second source of DC power in a steady state power mode.

A hollow cathode apparatus includes an outer tubular dielectric barrier circumferentially surrounding an outer tubular surface of the cathode tube, the outer tubular dielectric barrier being composed of a barrier material which is electrically non-conductive. Also disclosed is a system comprising the hollow cathode apparatus, an anode which is spaced from the output end of the tubular cathode, and electrical circuitry connected between the cathode tube and the anode for connection to a source of electrical power for providing an electrical potential between the cathode and anode to cause an electric current to pass from the emitter into the input gas to form a plasma which is then output through the output end of the cathode tube to form a plasma plume. The electrical circuitry comprises: a first power supply for connecting the cathode and the cathode electrode to a first source of DC power in an ignition power mode, wherein the first power supply comprises a current control device which is adapted to control the current between the cathode and the cathode electrode, wherein the current control device is arranged to function as an anti-surge current stabiliser; and a second power supply for connecting the anode and the cathode to a second source of DC power in a steady state power mode.

Systems and methods for material processing using wafer scale waves of precisely controlled electrons in a DC plasma is presented. A surface floating potential of a substrate placed atop a stage in a positive column of the DC plasma is adjusted and maintained to a reference potential. A periodic biasing signal referenced to the reference potential is capacitively coupled to the stage to control a surface potential at the substrate according to: an active phase for provision of kinetic energy to free electrons in the DC plasma for activation of targeted bonds at the surface of the substrate; a neutralization phase for repelling of the free electrons from the surface of the substrate; and an initialization phase for restoring an initial condition of the surface floating potential.

Some embodiments of the invention include a thruster system comprising a thruster and a pulsing power supply. The thruster may include a gas inlet port; a plasma jet outlet; and a first electrode. In some embodiments, the pulsing power supply may provide an electrical potential to the first electrode with a pulse repetition frequency greater than 10 kHz, a voltage greater than 5 kilovolts. In some embodiments, the pressure downstream from the thruster can be less than 10 Torr. In some embodiments, when a plasma is produced within the thruster by energizing a gas flowing into the thruster through the gas inlet port, the plasma is expelled from the thruster through the plasma jet outlet.

Some embodiments of the invention include a thruster system comprising a thruster and a pulsing power supply. The thruster may include a gas inlet port; a plasma jet outlet; and a first electrode. In some embodiments, the pulsing power supply may provide an electrical potential to the first electrode with a pulse repetition frequency greater than 10 kHz, a voltage greater than 5 kilovolts. In some embodiments, the pressure downstream from the thruster can be less than 10 Torr. In some embodiments, when a plasma is produced within the thruster by energizing a gas flowing into the thruster through the gas inlet port, the plasma is expelled from the thruster through the plasma jet outlet.

A plasma thruster comprises a cylindrical discharge channel (1), an injector (4), a RF antenna surrounding the discharge channel (1) and a device (3) for generating an axial static magnetic field in the discharge channel (1). The RF antenna is a cylindrical birdcage antenna (2) formed of several electrically conductive parallel legs (10) connected by two end rings (11) including capacitors (12) between adjacent legs (10) in each case. The two end rings (11) with the capacitors (12) are formed on two printed circuit boards (14) to which the legs (10) are attached, said printed circuit boards (14) having a through opening for the discharge channel (1). The antenna maximizes electrical coupling efficiency and provides resulting electromagnetic fields for quasi-neutral plasma acceleration along with the magnetic field effect provided by the externally applied magnetic field. This plasma thruster allows an easy upscaling or downscaling due to the printed circuit boards and is particularly suitable for low power applications like propulsion for smaller spacecrafts or satellites.

A plasma thruster comprises a cylindrical discharge channel (1), an injector (4), a RF antenna surrounding the discharge channel (1) and a device (3) for generating an axial static magnetic field in the discharge channel (1). The RF antenna is a cylindrical birdcage antenna (2) formed of several electrically conductive parallel legs (10) connected by two end rings (11) including capacitors (12) between adjacent legs (10) in each case. The two end rings (11) with the capacitors (12) are formed on two printed circuit boards (14) to which the legs (10) are attached, said printed circuit boards (14) having a through opening for the discharge channel (1). The antenna maximizes electrical coupling efficiency and provides resulting electromagnetic fields for quasi-neutral plasma acceleration along with the magnetic field effect provided by the externally applied magnetic field. This plasma thruster allows an easy upscaling or downscaling due to the printed circuit boards and is particularly suitable for low power applications like propulsion for smaller spacecrafts or satellites.

Systems and methods utilizing successive, axially symmetric acceleration and adiabatic compression stages to heat and accelerate two compact tori towards each other and ultimately collide and compress the compact tori within a central chamber. Alternatively, systems and methods utilizing successive, axially asymmetric acceleration and adiabatic compression stages to heat and accelerate a first compact toroid towards and position within a central chamber and to heat and accelerate a second compact toroid towards the central chamber and ultimately collide and merge the first and second compact toroids and compress the compact merge tori within the central chamber.