A method of accelerating charged particles in a plasma and an associated plasma accelerator and electromagnetic radiation source, the method including creating a region of non-uniform electric field within the plasma which propagates through the plasma; using the non-uniform electric field to accelerate a first plurality of charged particles in the direction of propagation of the region of non-uniform electric field; and once the accelerating first plurality of charged particles have propagated part-way through the plasma: adding a second plurality of charged particles to the plasma, such that the second plurality of charged particles propagates through the plasma, the second plurality of charged particles create a local distortion in the non-uniform electric field experienced by the accelerating first plurality of charged particles, and the local distortion in the non-uniform electric field propagates through the plasma with the accelerating first plurality of charged particles; and the method also including using the local distortion in the non-uniform electric field to accelerate the first plurality of charged particles in the direction of propagation of the region of non-uniform electric field.

A method of accelerating charged particles in a plasma and an associated plasma accelerator and electromagnetic radiation source, the method including creating a region of non-uniform electric field within the plasma which propagates through the plasma; using the non-uniform electric field to accelerate a first plurality of charged particles in the direction of propagation of the region of non-uniform electric field; and once the accelerating first plurality of charged particles have propagated part-way through the plasma: adding a second plurality of charged particles to the plasma, such that the second plurality of charged particles propagates through the plasma, the second plurality of charged particles create a local distortion in the non-uniform electric field experienced by the accelerating first plurality of charged particles, and the local distortion in the non-uniform electric field propagates through the plasma with the accelerating first plurality of charged particles; and the method also including using the local distortion in the non-uniform electric field to accelerate the first plurality of charged particles in the direction of propagation of the region of non-uniform electric field.

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 thruster has a first stage and a second stage. The first stage is a plasma source that outputs a plasma. The second stage is an accelerator. In one embodiment, the second stage is a plasma accelerator that accelerates the plasma. In another embodiment, the second stage is an ion accelerator that accelerates the ions from the plasma.

The MPD thruster improvements described here apply to coaxial gas-fed quasisteady self-field devices without auxiliary magnetic fields.

The MPD thruster improvements described here apply to coaxial gas-fed quasisteady self-field devices without auxiliary magnetic fields.

A heaterless hollow cathode provides electron emission current in an electric space propulsion system. A mechanical, thermal, and electromagnetic design of the cathode apparatus is presented, and a method of operation for rapid ignition and stabilization of the cathode is provided. The keeper of the cathode apparatus has a thickness change which reduces the flow of heat away from the cathode's emitter assembly. The method for heating the emitter assembly includes controlling applied voltages so that the current flowing from the emitter assembly to the keeper is maintained at a predetermined fixed value. By this method, damage to the electron emitting surfaces of the emitter assembly by electric arcing and/or by depletion of dopant materials is avoided.

A heaterless hollow cathode provides electron emission current in an electric space propulsion system. A mechanical, thermal, and electromagnetic design of the cathode apparatus is presented, and a method of operation for rapid ignition and stabilization of the cathode is provided. The keeper of the cathode apparatus has a thickness change which reduces the flow of heat away from the cathode's emitter assembly. The method for heating the emitter assembly includes controlling applied voltages so that the current flowing from the emitter assembly to the keeper is maintained at a predetermined fixed value. By this method, damage to the electron emitting surfaces of the emitter assembly by electric arcing and/or by depletion of dopant materials is avoided.

A vacuum arc thruster (VAT) for a propulsion system of a micro-satellite is provided. The VAT includes an anode, a cathode including a fuel, and an insulator between the anode and the cathode. The VAT is operable to create an arc between the anode and the cathode and discharge plasma through the diverging nozzle as thrust. The anode may define a diverging nozzle. The VAT may further include a Halbach array including a plurality of permanent magnets arranged in a ring, each of the permanent magnets of the ring having a radially inward positioned north pole and a radially outward positioned south pole.

An electron cyclotron resonance (ECR) thruster includes a magnetic field source configured to generate a magnetic field, a thruster body that defines a chamber, the thruster body being disposed relative to the magnetic field source such that the magnetic field is present in the chamber and such that a magnetic nozzle is established, an antenna configured to propagate radio frequency (RF) power within the chamber, and a waveform generator coupled to the antenna to generate an RF waveform for the RF power. The waveform generator is configured such that the RF waveform includes multiple frequencies.