A cusped-field thruster for a space system, wherein the cusped-field thruster comprises: at least two substantially annular permanent magnets arranged in an antipolar manner, wherein a magnetic pole piece is formed between the permanent magnets, and an anode, which comprises a permanent-magnetic material. The cusped-field thruster is configured such that a cusp is formed in a region adjacent to the anode of the cusped-field thruster.

The present invention relates to a high efficiency hollow cathode and a cathode system applying the same, and comprises: a tube comprising at least two refractory metal parts; a gas providing unit and a gas outlet which are respectively formed at the distal ends of the tube; and an insert mounted inside the tube. According to the present invention, since the present invention constitutes a hollow cathode using more than two substances, the present invention can not only enhance thermal stability, lifespan and efficiency, but also can reduce costs accordingly.

The invention is a Hall thruster that does not have any discharge channel, and magnetic pole piece. The Hall thruster utilizes permanent magnets to produce magnetic field with strong radial component in front of an annular anode, and expands propellant directly into vacuum through the anode acting also as a gas distributor. The invention reduces mass and complexity of conventional Hall thrusters, and offers a radical solution to discharge channel and magnetic pole piece erosion problem.

A Hall effect thruster arranged inside a wall and including a magnetic circuit and an electric circuit including an anode, a first cathode, and a voltage source. The magnetic circuit and the electric circuit are arranged in such a manner as to generate magnetic and electric fields around the wall. In every meridian section, the magnetic circuit presents an upstream magnetic pole and a downstream magnetic pole arranged at the surface of the wall and spaced apart from each other; and the anode and the first cathode are situated on either side of the upstream magnetic pole.

A Hall thruster apparatus having walls constructed from a conductive material, such as graphite, and having magnetic shielding of the walls from the ionized plasma has been demonstrated to operate with nearly the same efficiency as a conventional nonmagnetically shielded design using insulators as wall components. The new design is believed to provide the potential of higher power and uniform operation over the operating life of a thruster device.

A direct converter for an axisymmetric mirror confinement system provides a set of radially symmetric vanes charged to capture ions escaping along the axis of the confinement system and to convert their energy to electrical power. An electron trap positioned before the charged vanes uses a magnetic field to divert and collect electrons, separating them from the ions, and may support a radial electric field providing plasma control. The charged vanes may be constructed of or have a coating of a getter material absorbing neutrals derived from those ions after capture.

The invention is a Hall thruster that does not have any discharge channel, and magnetic pole piece. The Hall thruster utilizes permanent magnets to produce magnetic field with strong radial component in front of an annular anode, and expands propellant directly into vacuum through the anode acting also as a gas distributor. The invention reduces mass and complexity of conventional Hall thrusters, and offers a radical solution to discharge channel and magnetic pole piece erosion problem.

One or more embodiments relates to an air-breathing plasma thruster including a thruster wall, an anode, a cathode, and at least one ring electrode. The thruster wall defines a cylindrical channel, the cylindrical channel having a first end and an opposing second end in fluid communication with the first end, where the cylindrical channel is adapted to receive incoming airflow. The anode is at the first end of the channel and the cathode is at the second end of the channel opposite the first end. The at least one ring electrode is positioned on the thruster wall.

A direct converter for an axisymmetric mirror confinement system provides a set of radially symmetric vanes charged to capture ions escaping along the axis of the confinement system and to convert their energy to electrical power. An electron trap positioned before the charged vanes uses a magnetic field to divert and collect electrons, separating them from the ions, and may support a radial electric field providing plasma control. The charged vanes may be constructed of or have a coating of a getter material absorbing neutrals derived from those ions after capture.

The use of the electride form of 12CaO-7Al.sub.2O.sub.3, or C12A7, as a low work function electron emitter in a hollow cathode discharge apparatus is described. No heater is required to initiate operation of the present cathode, as is necessary for traditional hollow cathode devices. Because C12A7 has a fully oxidized lattice structure, exposure to oxygen does not degrade the electride. The electride was surrounded by a graphite liner since it was found that the C12A7 electride converts to it's eutectic (CA+C3A) form when heated (through natural hollow cathode operation) in a metal tube.