Abstract: An electron acceleration device uses thermionic fission cells, an electromagnetic scoop coil, and/or microwaves for power. A power control junction and electron injector control and feed free electrons in packets into the acceleration components that consist of a series of either induction module units, or radio-frequency linacs module units, having quadrapole magnet units in series between the induction module units or RF linac units. The RF linac and quadrapole series are surrounded by a Klystron series. At the high speed electron exit from the device, deflector plates control the exit path of the electrons to direct the course of a craft or electrons to a work area.

Abstract: The system (31 to 33, 34 to 38) for generating a magnetic field in the main channel of the plasma accelerator are adapted to produce, in the main channel (24) an essentially radial magnetic field at the downstream end (225) of the channel (24), its induction being maximum at this point. The magnetic field has a minimum induction in the transition area in the vicinity of the anode (25), the absolute induction value of the field increasing again upstream of the anode (25), in the region of the buffer chamber (23) in order to produce a magnetic mirror effect. The magnetic field lines include, between the anode (25) and the downstream end (225) of the channel (24), a concavity oriented downstream, causing focusing of ions, the maximum ionisation density area being located downstream of the anode (25).

Abstract: Carbon-carbon elements for ion optics sets are thermomechanically stable under the extreme temperature changes that are experienced in ion thrusters. The elements described include screen and accelerator grids and methods of producing such grids. The described elements are thermomechanically stable, lightweight, and resistant to sputtering.

Abstract: A satellite thruster system capable of creating a high velocity plasma jet is disclosed. The plasma accelerator, or "railthruster," features a high energy current pulse source and a geometrically configured coaxial or parallel dual-rail ignitor system for higher velocity, and thus more fuel efficient, satellite attitude control. A ratio of a length of the railthruster to a spacing between the rails is at least 3:1.

Abstract: Apparatus for an ion engine comprises a three-grid accelerator system with the decelerator grid biased negative of the beam plasma. This arrangement substantially reduces the charge-exchange ion current reaching the accelerator grid at high tank pressures, which minimizes erosion of the accelerator grid due to charge-exchange ion sputtering, known to be the major accelerator grid wear mechanism. An improved method for life testing ion engines is also provided using the disclosed apparatus. In addition, the invention can also be applied in materials processing.

Abstract: Internal and external magnetic screens made of magnetic permeable material are added between the discharge chamber and the internal and external sources of magnetic field, respectively. A longitudinal gap is maintained between the screens and their respective internal and external poles, that does not exceed half the distance between the internal and external poles. The exit end part of the internal magnetic screen is placed closer to the middle point of the accelerating channel than the internal pole. The walls of the exit end part of the discharge chamber are constructed with an increased thickness, and extend beyond the planes that the poles lay. The magnetic screens can be located with a gap relative to the magnetic path if connected by a bridge between the screens. The discharge chamber, the anode, and the magnetic system are symmetrically designed relative to two mutually perpendicular longitudinal planes.

Abstract: An apparatus is disclosed for the propulsion of water vehicles. A magnet field as well as an electric field with essentially perpendicular field lines are produced in a pipe through which surrounding water flows. In this manner, a force is exercised upon charge carriers within the surrounding water and this force is used as a propulsion force for the water vehicle. The pipe is surrounded by a solenoid coil which is arranged essentially coaxially to the pipe. A first electrode is arranged essentially along the axis of the pipe and a voltage source is switched between the electrode and the pipe, acting as a second electrode. An Archimedes' screw is arranged in the cylindrical gap between the electrode and the pipe in order to deflect the surrounding water circulating about the axis into an axial direction, or the screw is rotationally rigidly connected to a moving conductor arranged perpendicularly to the direction of the magnet field.

Abstract: The invention provides in an accelerator for accelerating a magnetized rotating plasma comprising a magnetic system arrange symmetrically around an axis, two electrodes (10, 11) extending symmetrically along said axis inside the magnetic system, said electrodes being spaced from each other in the transverse direction of said axis, two pulsed power sources connected to the magnetic system and the electrodes, respectively, and openings (18) in the inner electrode in a cross-section perpendicular to said axis for the supply of a neutral gas to the space defined by said electrodes, a method for controlling the operation of the accelerator wherein the magnetic field is confined to form a layer which comprises a first cylindrical portion (12) with a minor diameter and a second cylindrical portion (14) with a major diameter and a transition portion (13) interconnecting said first and second cylindrical portions being arranged axis-symmetrically around a common axis.

Abstract: A Primary Force Ring for magnetohydrodynamic propulsion of a vehicle including: an endless closed loop vehicle housing; a plurality of spaced pairs of positive and negative electric field plates coupled to at least one voltage source and mounted in the housing for generating a plurality of discrete spaced electric fields within the housing; and, a plurality of electromagnetic field coils mounted in the housing with one field coil intermediate each pair of field plates for generating an endless segmented closed loop magnetic field contained within the housing and intersecting the discrete electric fields at substantially right angles.

Abstract: Apparatus and methods for large-area, high-power ion engines comprise dividing a single engine into a combination of smaller discharge chambers (or segments) configured to operate as a single large-area engine. This segmented ion thruster (SIT) approach enables the development of 100-kW class argon ion engines for operation at a specific impulse of 10,000 s. A combination of six 30-cm diameter ion chambers operating as a single engine can process over 100 kW. Such a segmented ion engine can be operated from a single power processor unit.

Abstract: A method and an apparatus for propelling water vehicles in surrounding water are disclosed. The water has carriers of electrical charge. For propelling the water vehicle, the latter is provided with an elongate pipe being immersed in the water for allowing the water to flow therethrough along a longitudinal axis thereof. An electric field (E) is generated within the pipe with electric field lines extending radially with respect to the longitudinal axis. Further, a magnetic field is also generated within the pipe, the magnetic field having field lines extending circumferentially about the longitudinal axis. Thereby, a force (F) is exerted upon the charge carriers by simultaneous action of the electric field (E) and the magnetic field (B) on the charge carriers. The force (F) is directed parallel to the longitudinal axis to thereby propel the water vehicle.

Abstract: Fullerene propellants, which are stable carbon cage structures composed of even numbers of carbon atoms in the range of about 32 to 200 atoms, particularly a combination of conveniently obtainable C.sub.60 and C.sub.70, may be carried in solid form in a spacecraft, sublimated to produce the appropriate molecular propellant such as C.sub.60 or C.sub.70, which may then be ionized by DC discharge or RF radiation to efficiently produce specific impulses in the range above 1000 lbf -s/lbm.

Abstract: An ion beam and jet stream motor useful as motive and propulsive forces is formed by generating a collimated ion beam and projecting the collimated ion beam into an electrically charged, tubular electrode. This is done with an ion beam motor having a pointed electrode mounted adjacent an end of a tubular electrode coupled with a high voltage power supply. The generated ion jet stream is useful in controlling or extinguishing flames.

Abstract: Magnetohydrodynamic methods and apparatus for propelling a vehicle including: an endless closed loop vehicle housing; a plurality of spaced pairs of positive and negative electric field plates coupled to at least one voltage source and mounted in the housing for generating a plurality of discrete spaced electric fields within the housing; a plurality of electromagnetic field coils mounted in the housing with one field coil intermediate each pair of field plates for generating an endless segmented closed-loop magnetic field contained within the housing and intersecting the discrete electric fields at substantially right angles; a combustible fuel source; a plurality of microscopic rocket motors coupled to the fuel source with each rocket motor having a discharge nozzle disposed above and adjacent to respective different ones of the positive electric field plates for generating a plurality of plasma streams of positively charged fuel particles and free electrons; a plurality of ion deflection assemblies associa

Abstract: This invention discloses an engine for use in sustained space travel. The engine is of an electric type powered by a nuclear reactor. The electric engine includes a pulsed inductive magnetic thruster. A gas is discharged against an inductor comprising a series of parallel coils arranged in a spiral fashion. Each coil consists of four separate electrically connected coil sections. Each coil section traverses one-quarter of the distance around the inductor from an outer perimeter to an inner perimeter to form a single closed loop. A capacitor is electrically connected to two outer perimeter connector points for each coil forming a Marx Bank arrangement. All capacitors are charged to full charge and discharged simultaneously by a trigger generator immediately after a puff of propellant gas reaches the inductor. The high induced EMF in the inductor caused by the multiple capacitors in series in a single loop creates a rapidly rising magnetic field which ionizes the propellant gas.

Abstract: A hybrid chemical/electromagnetic propulsion system which combines thermal expansion of a chemically-reacted propellant with electromagnetic acceleration of the propellant to provide an efficient propulsion system that operates in the specific impulse I.sub.sp range of 800 to 2500 seconds. The hybrid chemical/electromagnetic propulsion system includes a reaction chamber, an expansion nozzle mounted to the exit of the reaction chamber, and an induction coil wound around a portion of the expansion nozzle. The reaction chamber supports the combustion or chemical reaction of a propellant to form high-temperature ionizable reaction products. The expansion nozzle then expands these high-temperature reaction products to generate thrust. The induction coil generates a varying electric and magnetic field which ionizes and magnetically accelerates the reaction products to generate additional thrust. A drive circuit supplies current to the induction coil in a manner that maximizes this additional thrust.

Abstract: An ion thruster is operable in an interplanetary space with plasma generated by microwaves in a propellant atmosphere. A vessel defines first, second and third hollow spaces and a window between the first hollow space and the second and third hollow spaces, the second hollow space having an opening. A microwave generating unit generates the microwave in the first hollow space as a standing wave penetrating into the second and thid spacers hollow. A propellant supplying unit supplies the propellant into the second and third hollow spaces, the propellant serving as a main and neutralizing propellant and absorbing the standing wave to produce main plasma comprising main ions and main elecrons. An accelerating unit accelerates only the main ions into an ion beam to inject the ion beam through the opening into the interplanetary space. A neutralizing unit defines a third space which is in communication to the first space and into which the standing wave penetrates.

Abstract: An ocean-going vessel comprises a stern power plant and side propulsion units attached to the starboard side and to the port side of the ocean-going vessel. Each side propulsion unit comprises two combined propulsion systems having tubular propellers and magnetohydrodynamic drives. The front and rear combined propulsion systems or the starboard side and the port side are united by a tube. Side propulsion units are adapted to provide additional thrust and maneuverability to the ocean-going vessel. Side propulsion units are adapted to provide braking actions by reversing combined propulsion systems.

Abstract: An electromagnetic ramjet propulsion system is provided for accelerating high mass payloads through the upper atomsphere at orbital velocities. The propulsion system comprises a plurality of coplaner self-supporting superconducting dipole coils several hundred meters in diameter that is initially accelerated to high altitude and supersonic speed by magnetic repulsive forces generated by a plurality of superconducting field coils several kilometers in diameter embeded beneath the earth's surface. The ramjet is accelerated to orbital velocities by a multigigawatt microwave beam that is transmitted from the earth's surface. A reflecting grid of conducting wires is mounted inside the inner dipole which shock ionizes the low dentisy atmospheric gas passing through it.

Abstract: A turbine power plant which produces power from a high temperature plasma and high voltage electricity. A plurality of ion repulsion discharge chambers are situated along the perimeter of the turbine to accelerate the ions and a condenser and pump are used to return the condensed gases back to a plasma generator.

Abstract: An ion thruster for accelerating positively charged ions produced by the collision of free electrons with gas atoms. An ion thruster (10,100) includes a cathode chamber (12, 60, 118) and an ionization chamber (14, 106). The outer surface of an emitter tube (28, 61, 128) is coated with a dielectric material to protect the emitter tube from sputtering erosion. A plurality of bar magnets (20, 22; 108, 110) are arranged in a spaced apart circular array around the cathode chamber with a pole face of each of the magnets tangentially aligned with wall sections (16, 18; 102, 104) of the ionization chamber. The bar magnets thus define a picket fence, wherein the magnetic field between adjacent bar magnets is used to extend the mean path of an electron entering the ionization chamber, improving the probability that it will impact an atom, creating an ion.A grid plate (112) comprises an accelerator grid (204) coated on its inner and outer surfaces with a dielectric coating (206, 208).

Abstract: A technique for producing thrust by generating a hybrid plume plasma exhaust is disclosed. A plasma flow is generated and introduced into a nozzle which features one or more inlets positioned to direct a flow of neutral gas about the interior of the nozzle. When such a neutral gas flow is combined with the plasma flow within the nozzle, a hybrid plume is constructed including a flow of hot plasma along the center of the nozzle surrounded by a generally annular flow of neutral gas, with an annular transition region between the pure plasma and the neutral gas. The temperature of the outer gas layer is below that of the pure plasma and generally separates the pure plasma from the interior surfaces of the nozzle. The neutral gas flow both insulates the nozzle walls from the high temperatures of the plasma flow and adds to the mass flow rate of the hybrid exhaust. The rate of flow of neutral gas into the interior of the nozzle may be selectively adjusted to control the thrust and specific impulse of the device.

Abstract: A means for controllably accelerating a particle of matter having a selected dipole characteristic is shown. The means includes a means for generating an alternating electric field extending a first direction, which varies at a selected frequency and which has a predetermined magnitude which is less than the characteristic field ionization potential limit of a particle. A means for generating an alternating magnetic field is provided. The alternating magnetic field extends in a second direction at a predetermined angle to and crosses and intercepts the electric field to define a spatial force field region. The alternating magnetic field has a frequency which is substantially equal to and is at a predetermined phase angle relative to the alternating electric field and is at a flux density which, when multiplied times the selected frequency, is less than the characteristic field ionization limit of a particle.

Abstract: An ion source has the typical chamber wherein ions are produced and caused to be propelled outwardly through at least a pair of grids which have a mutually-aligned respective plurality of apertures. Thus, there are the usual cathode, anode, magnet assembly, ionizable gas inlet and supporting power supplies as well as neutralizing means. First and second grids each have an integrally-formed peripheral marginal portion. A support element has a shape which matches and overlies the marginal portion of one grid, while a clamp has a shape which matches that of and overlies the other marginal portion. The support element and clamp are secured together. First and second mutually-aligned seats are successively spaced around the respective marginal portions.

Abstract: A hybrid electrothermal/electromagentic arcjet thruster has a cylindrical body with a longitudinal central axis, a plurality of electro-thermal propulsion mechanisms defined in the body in radially and circumferentially spaced relation about and extending along the central axis, and an electromagnetic propulsion mechanism defined in the body coaxially along the central axis thereof, between the electrothermal propulsion mechanisms and extending downstream thereof. Each electrothermal propulsion mechanism has tandemly-arranged constriction and expansion zones and are operable to concurrently receive a flow of gaseous propellant through the constriction zone and generate an electric arc therethrough to the expansion zone. The arcs interact with the propellant flows such that the latter are partially ionized and electrothermally accelerated through the expansion zones. The electromagnetic propulsion mechanism has an expansion chamber which communicates with, and extends downstream of, the expansion zones.

Abstract: A gas, ionizable to produce a plasma, is introduced into a region defined within an ion source. An anode is disposed near one end of that region, and a cathode is located near the other. A potential is impressed between the anode and the cathode to produce electrons which flow generally in a direction from the cathode toward the anode and bombard the gas to create a plasma. A magnetic field is established within the region in a manner such that the field strength decreases in the direction from the anode to the cathode. The direction of the field is generally between the anode and the cathode. The electrons are produced independently of any ion bombardment of the cathode, the magnet is located outside the region on the other side of the anode and the gas is introduced uniformly across the region.

Abstract: Apparatus for generating a stream of high temperature gaseous material comprises a pressure container having an inlet for air under pressure and a restricted outlet orifice. An electrode is within the container, insulated from it, and connected to a source of direct current; it has a discharge point adjacent and aligned with the outlet orifice. The wall of the orifice is conductive and connected to ground. The space between the electrode and the container may converge towards the outlet. A method in which air is compressed within a container having a restricted orifice, at least the portion of the air within the container which is adjacent the orifice is ionized, the excited electrons and ions discharging rapidly from the container through the orifice water or fuel may be introduced into the discharging material, for generation of steam or for combustion, respectively.

Abstract: An ion propulsion system is disclosed. The invention includes a ionizing system for ionizing a gaseous propellant within a chamber to produce a plasma. The ionizing system includes a cathode 14 to provide a source of electrons and anodes 11 and 13 to accelerate the electrons to velocitites sufficient to ionize the gaseous propellant. The invention further includes an ion extraction system 20 for expelling an ion beam from the plasma. A particularly novel aspect of the invention is the provision of a control system 45 and 46 for modulating the current of the ion beam by modulating the current through the anode 11 and 13.

Abstract: An axial electrostatic ion thruster for use on a dual-spin stabilized spacecraft is disclosed. The thruster is mounted on the spun portion of the spacecraft and continuously fired for an integral number of spin periods to provide north-south velocity and attitude control. To achieve zero attitude precession with a statically imbalanced despun platform, or an intentional attitude precession generally, the ion thrust is spin-synchronously varied between two non-zero levels to achieve a prescribed Fourier component amplitude and phase at the spin frequency. Modulation of the thrust is achieved with constant ion beam current by complementary modulation of the beam voltage, V.sub.B, and accel voltage, V.sub.A by varying the ion extraction system grid voltages. This varies the thrust while maintaining a constant total accelerating voltage V.sub.TOT =V.sub.B +.vertline.V.sub.A .vertline..

Abstract: A technique for producing thrust by generating a hybrid plume plasma exhaust is disclosed. A plasma flow is generated and introduced into a nozzle which features one or more inlets positioned to direct a flow of neutral gas about the interior of the nozzle. When such a neutral gas flow is combined with the plasma flow within the nozzle, a hybrid plume is constructed including a flow of hot plasma along the center of the nozzle surrounded by a generally annular flow of neutral gas, with an annular transition region between the pure plasma and the neutral gas. The temperature of the outer gas layer is below that of the pure plasma and generally separates the pure plasma from the interior surfaces of the nozzle. The neutral gas flow both insulates the nozzle walls from the high temperatures of the plasma flow and adds to the mass flow rate of the hybrid exhaust. The rate of flow of neutral gas into the interior of the nozzle may be selectively adjusted to control the thrust and specific impulse of the device.

Abstract: An isolator is provided which has an inlet at ground electrical potential which receives gas, and which has an outlet at a high electrical potential through which gas is discharged, the isolator being compactly and simply constructed while providing a long narrow path that minimizes the possibility of electrical breakdown through the gas. The isolator includes a first element forming a cylindrical core and a cup-shaped second element forming a sleeve portion that closely receives the core. The core has a helical groove on its outside to form a passage between the groove and the inner walls of the sleeve. The core also has a vertical hole extending to the bottom of the core and a radial groove in the bottom of the core that extends between the hole and the bottom of the helical groove.

Abstract: An emission current control system for balancing the individual emission currents from an array of hollow cathodes has current sensors for determining the current drawn by each cathode from a power supply. Each current sensor has an output signal which has a magnitude proportional to the current. The current sensor output signals are averaged, the average value so obtained being applied to a respective controller for controlling the flow of an ion source material through each cathode. Also applied to each controller are the respective sensor output signals for each cathode and a common reference signal. The flow of source material through each hollow cathode is thereby made proportional to the current drawn by that cathode, the average current drawn by all of the cathodes, and the reference signal. Thus, the emission current of each cathode is controlled such that each is made substantially equal to the emission current of each of the other cathodes.

Abstract: The electrostatic conveyor consists of a duct having an inlet and an outlet, and apparatus for generating travelling, curvilinear, AC fields along the length of the duct. Charged particles, of conductive or non-conductive materials, under electrostatic forces, are exposed to unidirectional, centrifugal forces so that they are moved along the duct from the inlet to the outlet.

Abstract: A dipolar force field propulsion system having a alternating electric field source for producing electromotive lines of force which extend in a first direction and which vary at a selected frequency and having an electric field strength of a predetermined magnitude, a source of an alternating magnetic field having magnetic lines of force which extend in a second direction which is at a predetermined angle to the first direction of the electromotive lines of force and which cross and intercept the electromotive line of force at a predetermined location defining a force field region and wherein the frequency of the alternating magnetic field substantially equal to the frequency of the alternating electric field and at a selected in phase angle therewith and wherein the magnetic field has a flux density which when multiplied times the selected frequency is less than a known characteristic field ionization potential limit; a source of neutral particles of matter having a selected dipole characteristic and having

Abstract: A multipole electron-bombardment type ion source includes an ion chamber defined by chamber walls and magnetic elements of an electrically insulating, permanently magnetized material. The magnetic elements provide mechanical support for anode elements and electrically isolate the anode elements from the chamber walls. In a preferred embodiment, the magnetic elements and the anode elements form a layered structure.

Abstract: An improved ion thruster (10) for low specific impulse operation in the 1500 sec to 6000 sec range has a multicusp boundary field (48) provided by high strength magnets (30-38) on an iron anode shell (14) which lengthens the paths of electrons from a hollow cathode assembly (20). A downstream anode pole piece in the form of an iron ring (40) supports a ring of magnets (44) to provide a more uniform beam profile. A cylindrical cathode magnet (46) can be moved selectively in an axial direction along a feed tube (22) to produce the desired magnetic field at the cathode tip (24).

Abstract: An improved power plant incorporating a gas turbine and a magnetohydrodynamic (MHD) generating means is provided wherein a plurality of coolant conducting fins are disposed in the diffuser region of the duct between the MHD generator and the turbine. The cooling fins are provided with means to supply compressed coolant to the diffuser duct for mixing with the combustion gases to provide optimum gas pressure, temperature and velocity for driving the turbine.

Abstract: A power circuit utilizing a switch comprised of Hall-effect-active resistive elements for interrupting a current flow in an inductive energy storage system. Interruption of the flow of current causes a high-voltage pulse which drives the current flow into a circuit leg which is parallel to the interrupting elements. The Hall effect switch is controlled by means of an exciter coil that is connected in parallel with the Hall-effect-active resistive elements to provide self excited operation.

Abstract: A field-emission ion source in which, under the influence of an electric field, ions are released from a metal or metal alloy present in an enclosed space in the liquid state. The ions are emitted from this space through a very narrow slit. This slit may be straight or curved. The field-emission ion source can be used in an ion thruster apparatus comprising an emitter module, an electrode system, and a power supply unit. A plurality of emitter modules can be combined to form an ion thruster apparatus having a greater ion current output. Instead of a liquid metal as the propellant, a metal in the solid phase can be supplied to the emitter module, which metal is melted in the emitter module.

Abstract: Ion chamber 20 receives electrons from cathode 28 and produces ions by electron bombardment in discharge plasma chamber 20. Ions are extracted through ion optics including screen 22 and accelerator electrode 24. Higher ion densities in the center of the discharge chamber are reduced by spoiler 42 which is operated at a potential between cathode and anode potential. This reduces double ionization and central peaking to provide a more uniform ion beam through the optics. By employing laterally positioned spoiler elements beam steering can be accomplished. The ion source is useful wherever a uniform beam profile is desirable as in ion implantation. Controlling the direction of beam density is useful in ion machining and in ion thrusters for space application.

Abstract: A plasma source constituting an ion accelerator operating in the presence of an intense magnetic induction for obtaining plasma of large transverse section and comprising a chamber having an inlet for gas and a device to produce electrical discharge at high frequency in the chamber to form a plasma from the gas. A plurality of parallel channels are disposed in axial extension from the chamber and a magnetic induction coil surrounds the channels for producing the intense magnetic induction in a direction parallel to the channels.

Abstract: An ion extraction system utilizing small hole accel grid (SHAG) optics is disclosed. A screen grid, an accel grid and a decel grid are positioned downstream of a neutral, highly ionized plasma source, and each of these grids have apertures in axial alignment. The accel grid has a relatively small aperture in the range of less than 50% to approximately 10% the size of the aperture of the screen grid. The electric field set up by the screen grid and the accel grid serve to extract an ion beam from the plasma source and focus the ion beam through the accel grid aperture. The small aperture in the accel grid is formed by drilling a relatively large aperture in the accel grid and then securing a thin metallic foil on at least the downstream face of the accel grid to cover the large, drilled aperture.The relatively small aperture is etched in the thin metallic foil by the ion beam.

Abstract: An ion prime mover or engine includes an ionization chamber closed up by a plasma boundary anchor. A field winding surrounds the ionization chamber for producing a high frequency electromagnetic alternating field. Such field ionizes a gas in the ionization chamber. The ion engine further includes an anode-cathode path for producing an electrostatic field, wherein the ionized gas is accelerated out of the ionization chamber through the apertures in the plasma boundary anchor and in the cathode. The high frequency electromagnetic alternating field is arranged in such a manner that this field is substantially undisturbed in the area of the plasma boundary anchor and that the field lines extend substantially perpendicularly to the surface of the plasma boundary anchor facing the ionization chamber.

Abstract: High current density ion source with high total current is achieved by individually directing the beamlets from an electron bombardment ion source through screen and accelerator electrodes. The openings in these screen and accelerator electrodes are oriented and positioned to direct the individual beamlets substantially toward a focus point.

Abstract: Typical embodiments of the invention can be used for photon generation, plasma containment or for atmospheric and/or space vehicle propulsion. Illustratively, a large dome of insulating material supports an array of smaller insulating domes. Conducting electrodes that are embedded in the external surfaces of these smaller domes are coupled to a high frequency alternating current. The electrical potential on these electrodes produces ionization in the medium external to the dome array. The ions, charged with a potential that is the same as electrode voltage, are repelled from the dome array in a preferred direction. This action establishes a resultant force that can be used to drive the array through the medium in a direction opposite to that of the ions. The ionization phenomena produced in accordance with the described technique also generates abundant photons.

Abstract: The invention is directed to a screen anode for an ion thruster. The anode is constructed of a woven mesh screen, preferably of a stainless steel wire cloth with a mesh size less than the intergrid gap or openings of the screen grid or accelerator grid systems of the ion thruster. The screen anode is sputter coated with tantalum as a result of thruster operation. Because of the fineness of the screen anode any spalled material from the tantalum coated anode is in such small dimensions that the spalled pieces cannot interfere with the accelerator and screen grid systems and with the focusing therebetween.

Abstract: An ion thruster beam shield is provided that comprises a cylindrical housing that extends downstream from the ion thruster and a plurality of annular vanes which are spaced along the length of the housing, and extend inwardly from the interior wall of the housing. The shield intercepts and stops all charge exchange and beam ions, neutral propellant, and sputter products formed due to the interaction of beam and shield emanating from the ion thruster outside of a fixed conical angle from the thruster axis. Further, the shield prevents the sputter products formed during the operation of the engine from escaping the interior volume of the shield.

Abstract: An electron-bombardment ion source has a chamber into which an ionizable propellant is introduced. Electrons flowing from a cathode to an anode serve to ionize the propellant. The resulting ions are accelerated out of the chamber. To increase the efficiency of ionization of the propellant by the electrons, a magnetic field is established within the chamber. To that end, there are a plurality of successively-spaced segments of electrically-conductive magnetic material. The segments are interconnected so as, collectively, to serve as the anode. Individually adjacent ones of the segments are respectively polarized as magnetic opposites, the segments together serving to establish the magnetic field.

Abstract: An electron-bombardment ion source includes a chamber into which a propellant is introduced. The propellant is ionized by means of electrons drawn toward an anode from a cathode. At one end of the chamber is an apertured screen followed by an aligned apertured grid. The grid is maintained at a potential that accelerates the ions out of the chamber through the screen and the grid and past a space-charge-neutralizing cathode. A resistor is connected between the grid and the neutralizing cathode in order to maintain the latter at a positive potential relative to the potential on the grid. A system ground preferably is connected to the junction between the resistor and the neutralizing cathode but, alternatively, may be connected between the grid and the resistor.

Abstract: An ion source includes apparatus that defines a region in which a supply of ions are produced. An apertured grid is disposed at one end of the region. A potential difference is impressed between the grid and the region so as to accelerate ions out of the region through the grid as a plurality of beamlets, the grid serving to focus those beamlets. To cyclically vary the degree of focus of the beamlets, the system as embodied further includes an arrangement for alternating a potential on the grid relative to a potential elsewhere in the ion source and to which the ions are subjected.