GB2588415A

GB2588415A - An apparatus for generating a force

Info

Publication number: GB2588415A
Application number: GB1915297.4A
Authority: GB
Inventors: Gaston Klemz Nicholas
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-10-22
Filing date: 2019-10-22
Publication date: 2021-04-28
Also published as: GB201915297D0; WO2021079090A1; EP4048890A1

Abstract

An apparatus 101 for generating a force comprising: a housing 103 having a cavity 104 therein; a magnet 109 arranged adjacent the housing so that the cavity contains a magnetic field with non-parallel magnetic field lines; and a cathode 117 and an anode, the arrangement being such that, in use, the cathode emits electrons 121 into the cavity which are deflected by the magnetic field such that a force acts between the magnetic field from the magnet and a magnetic field from the electrons and kinetic energy is transferred between the apparatus and the electrons. The cavity is preferably sealed and under vacuum.

Description

An apparatus for generating a force Embodiments of the present invention relate to an apparatus and method for generating a force. In some embodiments the apparatus may be a transducer. In some embodiments, the present invention relates to an actuator transducer that is also a bidirectional transducer. A bidirectional transducer can act as a thruster and a braking device.

Thrusters which are powered by electricity, for example ion thrusters, are known. An ion thruster operates by ionising atoms of a propellant such as Xenon in order to generate a plasma within an ionisation chamber. The positively charged Xenon ions are accelerated out of the chamber via magnetic rings in order to provide a propulsive force on the thruster in the opposite direction, according to Newton's third law. These types of thrusters are used on spacecraft for example space probes.

Unfortunately, whereas the electrical energy to power such a thruster can be readily harvested from solar energy radiating from a star such as the sun or generated by an onboard nuclear reactor, only a finite amount of propellant can be carried on the spacecraft. Although this arrangement is more efficient than chemical thrusters, the spacecraft must eventually be replenished with additional propellant. This limits the duration of acceleration such a spacecraft can undergo.

Some effort has been made to address this problem, for example modifying the thruster so that it takes in air molecules as the thruster passes through the atmosphere.

The thruster then utilises these air molecules as the propellant to generate the ionised plasma, and thereby negates the need for stores of propellant to be carried around with the thruster.

However, this method of operation assumes that the spacecraft and thruster are always able to pass into a suitable atmosphere of a planet during the course of a journey.

This may have an adverse effect on the journey time, distance and trajectory the spacecraft is able to travel.

The present invention in at least its preferred embodiment attempts to reduce this problem.

In an embodiment there is provided an apparatus for generating a force. The apparatus may comprise a housing having a cavity therein. The apparatus may comprise a magnet adjacent the housing, the magnet and housing arranged so that, in -2 -use, the cavity contains a magnetic field from the magnet, magnetic field lines within the cavity comprising non-parallel magnetic field lines. The apparatus may comprise a cathode capable of emitting electrons into the cavity. The apparatus may comprise an anode. The apparatus may be configured in the arrangement, such that, in use, the cathode emits electrons into the cavity and the electrons are deflected by the magnetic field from the magnet, such that a force acts between the magnetic field from the magnet and a magnetic field from the electrons and kinetic energy is transferred between the apparatus and the electrons. It may be that the magnetic field from the electrons is a magnetic field due to motion of the electrons.

Optionally, the apparatus is configured in the arrangement, such that, in use, the cathode emits electrons into the cavity and the electrons are deflected by the magnetic field from the magnet and kinetic energy is transferred between the apparatus and the electrons and a force is exerted on the apparatus.

Optionally, the cavity is sealed so as to contain a closed volume therein. It may be that the housing is provided with a first end cap and a second end cap, so as to seal the cavity. It may be that the cavity is under vacuum. It may be that the vacuum in the cavity is generated by a vacuum pump. It may be that the cavity is cylindrical in shape. It may be that the cavity has a tapered shape, such as a truncated cone shape. It may be that the cavity is a chamber.

It may be that the magnet is a permanent magnet. It may be that the magnet is an electromagnet. It may be that the polarity of the magnet is adjustable. It may be that the strength of the magnet is adjustable. It may be that the magnet is fixed to the first end cap of the housing.

It may be that other charged particles are used instead of or in addition to electrons. It may be that positrons are used instead of or in addition to electrons. It may be that protons are used instead of or in addition to electrons.

Optionally, one of the cathode and anode extends substantially centrally in an axial direction through the cavity. It may be that the axial direction is the direction of the axis of the cavity. It may be that the axial direction is the direction which is parallel to the longest side of the cavity.

Optionally, the apparatus further comprises a power source for maintaining a potential difference between the anode and the cathode so that, in use, there is an -3 -electric field between the cathode and the anode, the electric field and magnetic field from the magnet being such that, when the cathode is activated to emit electrons into the cavity, the electrons exhibit a vortex like flow about one of the cathode and anode which extends substantially centrally in an axial direction through the cavity. It may be that the power source is a mains electricity supply. It may be that the power source is at least one battery or at least one solar cell, or at least one nuclear reactor or at least one radioisotope thermoelectric generator or any combination thereof.

Optionally, the power source may enable a current to flow through the cathode, resulting in the emission of electrons from the cathode.

Optionally, the power source may power the electromagnet.

Optionally, the apparatus may further comprise a power source or a power supply or both.

Optionally the apparatus is adapted so that, in use, in the cavity, the magnetic field of the magnet comprises a component having a direction orthogonal to a direction

of a component of the electric field.

Optionally, the apparatus is adapted so that, in use, at least some of the electrons in the vortex perform an orbit within the cavity.

Optionally, the apparatus is adapted so that, in use, the vortex like flow of electrons generates a magnetic field. which interacts with the magnetic field of the magnet to generate the force on the apparatus.

Optionally, the apparatus is adapted so that, in use, in the cavity, the magnetic field of the magnet comprises a component having a direction parallel to a direction of a component of the magnetic field generated by the vortex like flow of electrons.

Optionally, the apparatus is adapted so that, in use, when the apparatus is moving, the non-parallel magnetic field lines in the cavity induce an electromotive force on the electrons in the vortex-like flow, which electromotive force tends to accelerate or decelerate the electrons depending on the direction of movement of the apparatus relative to the vortex-like flow of electrons.

Optionally, the apparatus is adapted so that, in use, the direction of the force on the apparatus and the direction of the electromotive force are substantially perpendicular to one another. -4 -

Optionally, the apparatus is adapted so that, in use, the force on the apparatus is a result of the interaction between the magnetic field from the magnet and the magnetic field from the vortex like flow of electrons which either accelerates or decelerates the apparatus.

Optionally, the apparatus is adapted so that, in use, the transfer of kinetic energy from the electrons to the apparatus, accelerates the apparatus.

Optionally, the apparatus is adapted so that, in use, the transfer of kinetic energy from the apparatus to the electrons, decelerates the apparatus.

Optionally, the cathode extends substantially centrally in an axial direction through the cavity and the anode is positioned at a radial distance from the cathode.

Optionally, the apparatus is adapted so that, in use, the force between the magnetic field from the magnet and the magnetic field from the vortex like flow of electrons is repulsive.

Optionally, the anode extends substantially centrally in an axial direction through the cavity and the cathode is positioned at a radial distance from the anode.

Optionally, the apparatus is adapted so that, in use, the force between the magnetic field from the magnet and the magnetic field from the vortex like flow of electrons is attractive.

Optionally, the apparatus further comprises a loop provided within the cavity, so that in use, electromagnetic radiation within the cavity induces a current in the loop.

Optionally, the apparatus is adapted so that, in use, the energy resulting from the induced current in the loop is reclaimed. It may be that the energy resulting from the induced current in the loop is dissipated as heat in a load.

Optionally, the apparatus further comprises a plate positioned relative to the housing and magnet so that in use the magnetic field is returned to complete a magnetic circuit.

In an embodiment, there is provided an apparatus comprising an apparatus according to an embodiment of the present invention, fixed to a first pole of a magnet and a second apparatus according to an embodiment of the present invention, fixed to the opposing pole of the magnet.

In an embodiment, there is provided a device, such as a vehicle, a rocket booster, a spacecraft or a space station comprising an apparatus in accordance with -5 -the present invention. In an embodiment, there is provided an object, such as a vehicle, a rocket booster, a spacecraft or a space station comprising an apparatus in accordance with the present invention. In an embodiment, there is provided an object comprising an apparatus in accordance with the present invention.

In an embodiment, there is provided a method of generating a force on an apparatus, the method comprising the following steps: providing an apparatus in accordance with an embodiment of the present invention; and activating the cathode to emit electrons into the cavity, for the electrons to be deflected by the magnetic field from the magnet, such that a force acts between the magnetic field from the magnet and a magnetic field from the electrons and kinetic energy is transferred between the apparatus and the electrons.

Use of an apparatus in accordance with the present invention as a thruster.

Use of an apparatus in accordance with the present invention as a braking device.

It may be that the apparatus is a transducer.

In some embodiments the apparatus does not require an exhaust for expulsion of reaction mass. -6 -

For a better understanding of the present invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which: Figure lA is a schematic block diagram of an object provided with an apparatus in accordance with the present invention; Figure 1B is a schematic side view in partial cross section of an apparatus in accordance with the present invention; Figure 2 is a side view in partial cross section along the line II-II of Figure 1B in a stage of operation; and Figure 3 is a side view in partial cross section along the line II-II of Figure 1B in a subsequent stage of operation.

Figure 4 is a schematic side view in partial cross section of the apparatus shown in Figure 1B, in a stage of use; Figure 5 is a schematic side view in partial cross section of the apparatus shown in Figure 1B, in a stage of use; Figure 6 is a side view in partial cross section along the line VI-VI of Figure 5, in a stage of use; Figure 7 is a front view of a prototype apparatus in accordance with the present invention, in a stage of assembly; Figure 8 is a front view of the prototype apparatus as shown in Figure 7, in a subsequent stage of assembly; Figure 9 is a perspective view of the prototype apparatus as shown in Figures 7 and 8, in a subsequent stage of assembly; Figure 10 is a schematic side view in partial cross section of an alternative embodiment of the apparatus as shown in Figure 1B, in accordance with the present invention; Figure 11 is a schematic side view in partial cross section of an alternative embodiment of the apparatus as shown in Figure 1B, in accordance with the present invention; and Figure 12 is a perspective view of a spacecraft provided with three apparatus in accordance with the present invention. -7 -

Referring to Figure 1A, there is shown an object which is generally identified by reference numeral 10. The object 10 may be any object which is intended to be moved from one location to another. For example, the object 10 may be a vehicle. A vehicle may be anything which is capable of transporting matter (such as people, animals, goods or equipment) from one location to another. In particular the vehicle may be a spacecraft, which in turn may be any craft or part of a craft which moves from one location in space to another location in space, for example, but not limited to a satellite, a space probe, a space shuttle or a space station.

The object 10 may be provided with an apparatus 101 in accordance with the present invention, which, in use applies a force to the object 10. The object 10 may be provided with a power source 12 to power the apparatus 101. The object 10 may be provided with a sensor 14, for example, to measure the position (such as the altitude) of the object 10. The sensor 14 may measure the speed of the object 10. The object 10 may be provided with a control unit 16 which may control the apparatus 101, the power source 12 and the sensor 14. The object 10 may be provided with a transmitter 18 which may be connected to the control unit 16, to allow the control unit 16 to communicate with external equipment (not shown).

As better shown in Figure 1B, the apparatus 101 comprises a housing 103 which is tubular in shape, the housing 103 has a cavity 104 therein, defining an enclosed volume. The housing 103 is provided with a first end cap 105 and a second end cap 107 which both seal the respective ends of the housing 103. The first end cap 105 and the second end cap 107 are both manufactured from a magnetically permeable material such as soft iron, whereas the housing 103 is manufactured from a conductive metal such as copper.

A bar magnet 109 is secured to the first end cap 105 at the north pole of the bar magnet 109. The free end of the bar magnet 109 is the south pole. The arrangement is such that the magnetic field from the bar magnet 109 emanates into the cavity 104. The magnetic field which emanates into the cavity 104 is non-parallel with respect to the walls of the cavity 104, which extend in the axial direction. This is so that the flux density of the magnetic field through the cavity 104 varies along the axis of the cavity 104. In this embodiment there is a major component of the magnetic field directed parallel to the axial direction of the cavity. -8 -

A plate 111 with a first end 113 and a second end 115 is positioned adjacent the bar magnet 109 and the housing 103, such that the first end 113 of the plate 111 is adjacent the south pole of the bar magnet 109 and the second end 115 of the plate 111 is adjacent the second end cap 107. The plate 111 is manufactured from a magnetically permeable material, such as iron.

A cathode 117 runs through the centre of the housing 103 and the cavity 104 in an axial direction, from the first end cap 105 to the second end cap 107. The cathode 117 is configured to act as a hot cathode and can emit electrons via thermionic emission.

A loop 119 is secured inside the housing 103, so that it extends from an inner surface of the housing 103 into the volume contained within the cavity 104. The loop 119 is a small loop antenna and is connected to an electrical load (not shown).

In operation, the volume within the cavity 104 is under vacuum and the cathode 117 and the housing 103 are connected to the power source 12, such that the housing 103 (wall of the cavity 104) acts as an anode. A current is passed through the cathode 117, and a potential difference between the cathode 117 and the positively charged anode (housing 103) creates an electric field therebetween.

As better shown in Figure 2, electrons are emitted from the cathode 117 and under action of the electric field, they move radially away from the cathode 117 towards the housing 103. For simplicity only a single electron 121 is shown in Figures 2 to 4. The electron 121 is travelling with an initial velocity in the direction of arrow A from the cathode 117 to the housing 103.

The magnetic field from the bar magnet 109 (the major component 116 of which is directed out of the page) is perpendicular to the initial trajectory of the electron 121. This arrangement gives rise to a Lorentz force acting on the electron 121 in the direction of the arrow B, which is perpendicular to the initial direction of travel of the electron depicted by arrow A. The Lorentz force arrow B is also perpendicular to the direction of the major component 116 of the magnetic field from the bar magnet 109.

The effect of the Lorentz force is that the initial trajectory of the electron 121 is altered as a result of the combination of forces acting on it. The net force from the force component of the electron 121 accelerating in the electric field (arrow A) and the Lorentz force component (arrow B), results in the electron 121 moving in a new direction which is depicted by arrow C. -9 -The same principle applies to the electron 121 subsequently moving in its new direction (arrow C), as better shown in Figure 3. The major component 116 of the magnetic field from the bar magnet 109 is still emanating in the same direction which is out of the page. Therefore, a Lorentz force acts on the moving electron 121 in a direction which is both perpendicular to the direction of the magnetic field and the direction in which the electron 121 is traveling in. The direction of the Lorentz force on the electron 121 is depicted by the arrow D. Again, the net force from the force component of the electron 121 accelerating in the electric field (arrow C) and the Lorentz force component (arrow D), results in the electron 121 moving in a new direction which is depicted by arrow E This effect occurs again and again, such that there is a continuous change in the trajectory of the electron 121. The overall trajectory is effectively a curve and the electron 121 spirals outwardly from and around the cathode 117. With the configuration as described, the electron 121 will travel in an anticlockwise path around the cathode 117 in the view of Figures 2 and 3.

The electric field between the cathode 117 and the housing 103 and the magnetic field from the bar magnet 109 are configured in a specific way, such that the Lorentz force equals the centripetal force on the electron 121. The resultant trajectory of the electron 121 around the cathode 117 is a continuous loop. In this way the electron 121 is able to continuously travel around the cathode 117 in a substantially circular orbit.

In operation, electrons are continuously emitted from the cathode 117 along its length. These electrons are acted upon by the Lorentz force resulting in individual circular orbits around the cathode 117 for each electron. The accumulation of these orbits is effectively a vortex-like flow of electrons travelling around the cathode 117 within the vacuum of the housing 103.

The effect of the vortex of electrons is similar to the effect produced by a coreless solenoid. In particular, a current traveling around a coreless solenoid will generate a magnetic field. In the same way, the vortex of electrons orbiting the cathode 117 generates a magnetic field. It should be apparent that the difference between the vortex of electrons and a coreless solenoid, is that the electrons travel around in the vortex motion without passing along coils of wire. A further way to view the vortex of electrons is as a coreless, wireless solenoid.

-10 -The vortex of electrons travels in an anticlockwise direction as shown in Figures 2 and 3. The direction of travel of the electron 121 (a single electron in the vortex) about the cathode, is also shown in Figure 4.

The vortex-like flow of electrons will create a magnetic field having a major component which will point into the page on which Figure 2 is displayed. This major component of the magnetic field will point in the opposite direction to the major component 116 of the magnetic field emanating from the bar magnet 109. The effect of this is that the vortex of electrons repels the bar magnet 109 and the overall repulsive magnetic forces act to push the bar magnet 109 (with the housing 103 fixed thereto) and the vortex of electrons apart. The directions of these repulsive forces are indicated by the arrows Z and Y shown in Figure 4.

The repulsive forces cause the apparatus 101 to move relative to the vortex of electrons which are within the housing 103 of the apparatus 101. The result of this is that the vortex of electrons experiences a change (reduction) in flux therethrough as the bar magnet 109 moves away from the vortex.

In accordance with Faraday's law, the change in flux through the vortex of electrons will induce an emf in the vortex. Normally the induced emf would drive an induced current which opposes the change in accordance with Lenz's law (i.e. the direction of the induced current would generate a magnetic field which would be in a direction so as to oppose for the change in flux). However, in this arrangement the induced emf slows down the electrons orbiting in the vortex. The induced emf is not sufficient to reverse the flow direction of electrons in the vortex.

The net effect of the induced emf slowing down the electrons is that the initial electrons in the vortex orbiting around the cathode 117 are decelerated so much so that the balance between the Lorentz force and the centripetal force is tipped and the electrons spiral outwardly from their circular orbit around the cathode 117 and fall into the anode (housing 103).

The cathode 117 is continuously emitting electrons at points along its length (during operation of the apparatus 101) and the electrons which crash into the housing 103 are continuously being replaced by newly emitted electrons. In this way, the vortex of electrons is substantially continuously being replenished and there is a substantially constant repulsive force between the bar magnet 109 and the vortex of electrons.

At any particular point in time, the vortex of electrons is stationary in space (in the horizontal dimension with a view to Figure 1B) and the bar magnet 109 and the housing 103 are constantly moving away from the vortex of electrons. In essence the vortex of electrons is constantly being diminished and replenished at a new position in space as electrons are emitted from the cathode 117 (as the cathode 117 is also moving through space along with the housing 103 and bar magnet 109). Electrons are being released from the cathode 117 and into the vortex at a front portion of the vortex and electrons are spiralling outward from the vortex and crash into the housing 103 from a rear portion of the vortex.

For a better understanding of the vortex of electrons, reference is now made to Figure 5. There is shown an approximate region F in the cavity 104 which is the closest region to the bar magnet 109 and so has stronger magnetic flux emanating therethrough relative to regions of the cavity further away from the bar magnet. Because of this, it is envisaged that electrons emitted from the cathode 117 in region F are strongly deflected by the Lorentz force and so may not be able to orbit the cathode 117 in a substantially circular orbit. These electrons may tend to be forced back towards the cathode 117. Some electrons may crash back into the cathode 117 and cause secondary emissions. Region H is the furthest region in the cavity 104 from the bar magnet 109 and so has a weaker magnetic flux emanating therethrough relative to regions of the cavity nearer to the bar magnet. Because of this, it is envisaged electrons emitted from the cathode 117 in region F are only weakly deflected by the Lorentz force and so may not be able to orbit the cathode 117 in a substantially circular orbit. These electrons may tend to travel from the cathode 117 to the anode (housing 103) under only a small deflection.

Region G is a region in the cavity 104 which is situated between region F and region H. The strength of magnetic flux emanating through the cavity 104 in region G is between the strength of flux in regions F and H. In region G, the force components from electrons accelerating in the electric field and the Lorentz force are more balanced compared to in regions F and H. Because of this, it is envisaged electrons emitted from the cathode 117 in region G tend to be deflected so as to orbit the cathode 117 in a substantially circular orbit.

-12 -The paths of electrons in the regions F, G and H are shown in Figure 6, which is a partial cross section of the apparatus 101, if being viewed from the right-hand side of Figure 5. The configuration of the apparatus 101, magnetic field strength from bar magnet 107, current through cathode 117 and electric field between the cathode 117 and the anode is such that region G is maximised. This is so that the vortex of electrons in the cavity 104 is also maximised and consequently minimising regions F and H. In operation, the momentum and kinetic energy from the electrons as they are slowed down is transferred to the bar magnet 109 and the housing 103 and so in this way, momentum and energy are conserved. Newton's third law is also met, by the action force (repulsive force between the vortex and the bar magnet 109, pushing the bar magnet 109 and housing 103 forward) having an equal reaction force (induced emf slowing down the electrons in the vortex). Due to Faraday's law and Lenz's law, the action and reaction forces are in fact perpendicular to each other.

The action force on the bar magnet 109 and housing 103 is in a forward direction (which is to the left in Figure 1B and into the page in Figure 2). The reaction force due to the emf slowing down the electrons in the vortex, acts in a clockwise direction (when viewed in Figures 2, 3 and 6).

The movement of electrons within the cavity 104 in this way can result in the emission of unwanted electromagnetic radiation within the cavity 104. This is removed via the loop 119 which in turn is connected to a load, for example a block of polymer resin mixed with black copper oxide powder. The unwanted electromagnetic radiation partly results from bremsstrahlung radiation radiating outwardly from the anode housing 103, resulting from the decelerated electrons from the vortex crashing into the anode housing 103. Unwanted electromagnetic radiation is also emitted when electrons are accelerated within the housing 103. The oscillating magnetic field component of the unwanted electromagnetic radiation, induces a current in the loop 119 in accordance with Faraday's law.

This arrangement provides the apparatus 101 with a substantially continuous forward propulsive force so as to act as a thruster, so long as it is electrically powered.

Advantageously it may not need to carry or process any propellant material.

The apparatus 101 has been demonstrated via a protype apparatus 201 (Figures 7 to 9). The protype was manufactured in the following way.

-13 -The outer casings of two unused dial-controlled microwave ovens were removed to expose the inner workings and the thermal cut-outs were disconnected from respective magnetron assemblies in respective microwave ovens. The thermal cut outs were left connected in the electrical circuits of the respective microwave ovens. The electrical connections to each magnetron assembly in both of the ovens were disconnected and both magnetron assemblies were removed from the remainder of their respective ovens.

The first magnetron assembly (not shown) was taken apart, with its metal plates unscrewed and both permanent magnets removed. As shown in Figure 7, the second magnetron assembly 223 had its right plate and its right permanent magnet 225 removed in order to expose the antenna 227. The right permanent magnet 225 was placed on the left-hand side of the magnetron box 229, which magnetron box 229 shields the electrical connections to the second magnetron assembly 223 (Figure 8).

The right permanent magnet 225 was placed such that its orientation is attractive to the left permanent magnet 231 which remains in the second magnetron assembly 223 and is adjacent the copper housing 203 of the second magnetron assembly 223. The two harvested permanent magnets 233 from the first magnetron assembly were stacked in the attractive orientation adjacent the newly relocated right permanent magnet 225, on the left-hand side of the magnetron box 229 of the second magnetron assembly 223.

The harvested permanent magnets 233, the right permanent magnet 225 and the left permanent magnet 231 together effectively form a bar magnet 209. The strength of the bar magnet 209 is approximately 0.888 T and it is manufactured from AINiCo. The rearrangement of the harvested permanent magnets 233 and the right permanent magnet 225, together with the left permanent magnet 231 created a magnetic field emanating inside a cavity of the second magnetron assembly 223, which magnetic field contained non-parallel magnetic field lines. In the prototype apparatus 101 there was a major component of the magnetic field directed parallel to the axial direction of the cavity. A 50mm by 50mm iron angle [plate 211 (not shown) was secured to the second magnetron 223, so that one face of the plate 211 rests against the free end of the bar magnet 209 and the other face of the plate 211 lies parallel to the side of the second -14 -magnetron assembly 223. Aluminium foil tape was used to secure the plate 211 in position.

A 100mm by 100mm by 50mm plastic TupperwareTm box and its lid was then lined with aluminium foil tape. Black copper II oxide power was mixed into a filler (PolyfillaTm) which was poured into the TupperwareTm box.

A hole in the lid of the Tupperware TM box was cut to a size that the antenna 227 would fit through. The lid was then placed onto the TupperwareTm box containing the filler mixture and the antenna 227 of the first magnetron was inserted through the hole in the lid and into the filler mixture. This was then left overnight for the filler to cure. The antenna 227 was removed post curing.

A metal box 235 with dimensions 150mm by 150mm by 170 mm was provided and its metal lid 237 removed. The TupperwareTm box and filler mixture was secured to the inside of the lid 237 with aluminium foil tape. Four small holes were made in the lid 237 and the second magnetron assembly 223 was then mounted on the Tupperwarem box via its antenna 227, so that the antenna 227 passed through the lid 237 of the TupperwareTm box and into the cured filler mixture. Tying wire was then used to secure the second magnetron assembly 223 to the lid 237 via the four small holes.

A hole through the wall of the box 235 was made and two high tension (HT) cables 239 (suitable for at least 2 kV at 1 Amp) passed through from the outside to the inside of the box 235. The HT cables 239 were connected via spade connectors to the second magnetron's electrical connectors, residing in the magnetron box 229. A third HT cable 239 was connected to the body of the box 235. The HT cables 239 were secured together at regular 300mm intervals with insulation tape.

The box 235 was then carefully placed over the second magnetron assembly 223 which in turn was mounted to the lid 237 of the box 235. The box 235 was positioned to engage its lid 237 and the connection between lid 237 and box 235 was sealed with aluminium tape 241.

A towel rail holder 243 was secured to the outside wall of the box 235 at a position along the line of the centre of gravity of the box 235. The towel rail holder 243 was secured to the box 235 via an epoxy adhesive and left to cure. The towel rail holder 243 was secured to the same side of the box 235 as the hole in which the HT cables 239 pass through.

-15 -The free ends of the HT cables 239 were connected to the electrical connectors of one of the microwave ovens, via spade connectors. The HT cable 239 which was connected to the body of the box 235 was connected to the earth terminal of the microwave oven.

The hole in the box 235 in which the HT cables 239 extended out from was filled with epoxy adhesive in order to minimise strain on the HT cables 239.

A bicycle maintenance stand was erected and the box 235 suspended from the stand via fishing wire about the towel rail holder 243 secured to the box 235. The box 235 was suspended several centimetres above the ground in a pendulum arrangement.

It was important to ensure that the HT cables 239 extending from the box 239 were not dragging on the ground nor that they inhibited the movement of the box 235, so that the box 235 could swing reasonably freely.

A suction cup mirror was secured to the top side of the box 235. Two laser pointers were set up on respective tripods. A first laser was directed at the mirror mounted on the metal box, which reflects the laser onto a target area, such as the ceiling or wall. The second laser (control laser) was arranged to be aimed directly onto the target area so that the beams cross over and are both incident upon the same point on the target area.

The microwave oven was plugged into an extension cable, which in turn was plugged into a mains supply electricity socket. The microwave oven was set on full power via the mechanical dial to operate for two minutes. The mains power supply was then switched on, powering the second magnetron assembly 223. Movement of the box 235 in the forward direction was observed by way of the laser dot on the target area resultant from the laser light reflected off of the mirror on the metal box, moving away from the control laser dot on the target area. The control laser dot on the target area did not move.

This demonstrated that the protype apparatus 201 generated a force. The prototype apparatus 201 has a mass of approximately 1.5 kg and in operation has demonstrated a deflection of approximately 3mm from a stationary position, whilst suspended from the stand. It has been estimated that the forward force of the thruster 201 during operation is approximately 100 mN.

-16 -The housing 203 of the second magnetron assembly 223 houses a cathode 217, which in operation emits electrons via thermionic emission. The housing 203 itself acts as an anode. The voltage drop between the terminals of the cathode 217 is approximately 3.3 V. The housing 203 (anode) is held approximately 2KV above the cathode 217. The current in the cathode 217 is between 8 Amps and 12 Amps and preferably 10 Amps DC.

The box 235 acts as a faraday cage in order to shield against unwanted electromagnetic radiation radiating outwardly from the anode housing 203, resulting from the decelerated electrons from the vortex crashing into the anode housing 203 or radiation emitted by electrons accelerating.

In the prototype, the microwaves emitted from the antenna 227 are absorbed by the black copper II oxide filler mix, in the TupperwareTm box and are dissipated as heat.

The prototype apparatus 201 was electrically powered from a UK mains supply. Depending on the intended use, other power sources could be employed to power the apparatus 101, including for example batteries, solar cells, nuclear reactors and radioisotope thermoelectric generators.

The apparatus 101 may also be used to generate a braking force when the apparatus 101 is moving due to external forces. For example, the apparatus 101 may be free falling with a force due to gravity and is moving in the direction to the right when viewed in Figure 4.

In this scenario, the apparatus 101 is powered and in operation to generate a vortex of electrons orbiting around the cathode 117 as previously described. As before, there is a repulsive force between the bar magnet 109 and the vortex of electrons. In this situation however, the bar magnet 109 is moving towards the vortex of electrons under the external force due to gravity, overcoming the magnetic repulsion force. The vortex of electrons on this occasion experience an increase in flux as the bar magnet 109 moves closer towards them.

In accordance with Faraday's law, an emf is induced in the vortex of electrons, which would normally induce a current in the direction to oppose the change in magnetic flux, in accordance with Lenz's law. In this case, the emf acts to increase the rate of flow and speed of the electrons moving in the vortex and increase the current. This increases the magnetic field generated by the vortex of electrons which, as described before, -17 -opposes the increase in flux from the bar magnet 109 as it moves closer to the vortex. This increase in electron speed and current flow in the vortex, opposes the initial change in magnetic flux in the cavity 104 in accordance with Lenz's law.

The effect of this is that the momentum and kinetic energy of the apparatus 101 are transferred to the electrons in the vortex. The apparatus 101 reduces its speed, whilst the electrons in the vortex increase their speed. The centripetal force on the electrons increases and they orbit the cathode 117 with an orbit of a smaller radius. At a specific point in time the vortex of electrons is stationary in space (in a horizontal dimension with a view to Figures 1B and 4) and it is the bar magnet 109 which is constantly moving towards the vortex. As the apparatus 101 moves relative to the vortex, the first end cap 105 of the housing 103 comes into contact with the orbiting electrons at the closest end of the vortex to it. The electrons collide with the atoms in the first end cap 105 and are decelerated, resulting in the emission of bremsstrahlung electromagnetic radiation within the cavity 104. This electromagnetic radiation along with other unwanted electromagnetic radiation in the cavity 104 (resulting from electrons accelerating) can induce a current in the loop 119, which electrical energy is then dissipated as heat in the electrical load.

In this way, the kinetic energy of the apparatus 101 has been transferred to the electrons and then dissipated as heat, ultimately slowing down the apparatus 101. In this arrangement, the apparatus 101 may act as a braking device.

It is also conceivable that the apparatus 101 can function as a braking device in the event when the electric field between the cathode 117 and the housing 103 is zero. In this situation, electrons are being emitted from the cathode 117 into the cavity 104, however they are not being accelerated in an electric field towards the housing 103, because the potential difference between the cathode and the housing 103 is zero.

In this scenario, the apparatus 101 is moving due to external forces, for example it is free falling with a force due to gravity and is moving in the direction to the right when viewed in Figure 4. The movement of the bar magnet 109 towards the electrons, increases the flux therethrough. The electrons move within the cavity 104 in response to the increase in flux from the bar magnet 109, effectively creating eddy currents. In accordance with Lenz's law, the electrons move in a way, so that the induced emf which drives the eddy currents is in a direction that opposes the increase in flux from the bar -18 -magnet 109. The result of this is that the movement of the bar magnet 109 is slowed down, with its kinetic energy and momentum being transferred to the electrons within the cavity 104.

An alternative embodiment of an apparatus 301 is shown in Figure 10. The apparatus 301 is nearly identical to the apparatus 101 as previously described, in that the apparatus 301 comprises a housing 303 which is tubular in shape, the housing 303 has a cavity 304 therein, defining an enclosed volume. The housing 303 is provided with a first end cap 305 and a second end cap 307 which both seal the respective ends of the housing 303. A bar magnet 309 is secured to the first end cap 305 at the north pole of the bar magnet 309 and the south pole is free.

The primary difference between apparatus 301 and apparatus 101 is that apparatus 301 comprises a central anode member 318 and an annular cathode 317 within the cavity 304. The annular cathode 317 is spaced radially from the central anode member 318. The annular cathode 317 is a hot cathode and is configured to emit electrons into the volume contained within the cavity 304.

In this arrangement, in use, a potential difference is applied between the annular cathode 317 and the central anode member 318, to create an electric field therebetween. The housing 303 is held negative with respect to the annular cathode 317, in order to force electrons emitted by the annular cathode 317 towards the central anode member 318 at the centre of the cavity 304. Both the annular cathode 317 and the central anode member 318 run through the centre of the housing 303 and the cavity 304 in an axial direction, from the first end cap 305 to the second end cap 307.

As before, this arrangement is such that the magnetic field from the bar magnet 309 emanates into the cavity 304. The magnetic field which emanates into the cavity 304 is non-parallel with respect to the walls of the cavity 304, which extend in the axial direction. This is so that the flux density from the magnetic field through the cavity 304 varies along the axis of the cavity 304. In this embodiment there is a major component of the magnetic field which is directed parallel to the axial direction of the cavity 304.

A plate 311 with a first end 313 and a second end 315 is positioned adjacent the bar magnet 309 and the housing 303, such that the first end 313 of the plate 311 is adjacent the south pole of the bar magnet 309 and the second end 315 of the plate 311 is adjacent the second end cap 307. A loop 319 is secured inside the housing 303, so -19 -that it extends from an inner surface of the cavity 304 into the volume contained therein. The loop 319 is a small loop antenna and is connected to an electrical load (not shown).

In use, the volume within the cavity 304 is under vacuum and the apparatus 301 is connected to a power source. The apparatus 301 is activated and the annular cathode 317 emits electrons in the volume contained within the cavity 304, which accelerate inwardly towards the central anode member 318 through the electric field.

The same principle as previously described would apply, in that the electrons emitted from the annular cathode 317 into the cavity 304, would be deflected by the Lorentz force, resulting from the electrons moving through a perpendicular major component of the magnetic field in accordance with Faraday's law. The combination of Lorentz force and force due to acceleration of the electrons in the electric field would allow the electrons to orbit the central anode member 318 in a vortex like flow.

In this embodiment the major component of the magnetic field generated by the vortex of electrons is in the same direction as the major component of the magnetic field from the bar magnet 309. The effect of this is that there would be an attractive force between the bar magnet 309 and the major component of the magnetic field generated by the vortex of electrons. The attractive forces cause the apparatus 301 to move relative to the vortex of electrons which are within the cavity 304 of the apparatus 301. The result of this is that the vortex of electrons experiences a change (increase) in flux therethrough as the bar magnet 309 moves towards the vortex.

The net effect of the induced emf slowing down the electrons is that the initial electrons in the vortex orbiting around the central anode member 318 are decelerated so much so that the balance of forces on the electrons is tipped and the electrons spiral inwardly from their substantially circular orbit around the central anode member 318 and fall into and collide with the central anode member 318.

-20 -As before, the momentum and kinetic energy from the electrons in the vortex is transferred to the apparatus 301. This arrangement provides the apparatus 301 with a substantially continuous propulsive force so as to act as a thruster. The direction of thrust on the apparatus 301 is to the right in Figure 10. In this way, energy and momentum are conserved.

The apparatus 301 can be used to generate a braking force, when the apparatus 301 is moving, in the same way as previously described in relation to apparatus 101. For example, the apparatus 301 may be free falling with a force due to gravity and is moving in the direction to the left when viewed in Figure 10.

In this scenario and as described above, the apparatus 301 is powered and in operation to generate a vortex of electrons orbiting around the central anode member 318, such that there is an attractive force between the bar magnet 309 and the vortex of electrons. In this situation however, the bar magnet 309 is moving away from the vortex of electrons under the external force due to gravity. The vortex of electrons on this occasion experience a decrease in flux the bar magnet 309 moves further away from them.

In accordance with Faraday's law, an emf is induced in the vortex of electrons and acts to increase the rate of flow and speed of the electrons moving in the vortex and increase the current. This is in order to increase the magnetic field generated by the vortex of electrons, which is directed in the same direction to the magnetic field emanating from the bar magnet 309. This increase in electron speed and current flow in the vortex, opposes the initial change in magnetic flux in the cavity 304, in accordance with Lenz's law.

As described in the previous embodiment, electrons will emit electromagnetic radiation, when they are accelerated and when they collide with the anode. This radiation can then be dissipated.

In this way, the kinetic energy of the apparatus 301 has been transferred to the electrons and then dissipated as heat, ultimately slowing down the apparatus 301. In this arrangement, the apparatus 301 may act as a braking device.

It is also conceivable that the apparatus 301 can function as a braking device in the event when the electric field between the annular cathode 317 and the central anode member 318 is zero. In this situation, electrons are being emitted from the annular -21 -cathode 317 into the volume within the cavity 304, however the electrons are not being accelerated in the electric field towards the central anode member 318 (as previously described), because the potential difference between the annular cathode 317 and the central anode member 318 is zero.

In this scenario, as before, the apparatus 301 is moving due to external forces, for example it is free falling with a force due to gravity and is moving in the direction to the left when viewed in Figure 10. The movement of the bar magnet 309 towards the electrons, decreases the flux therethrough. The electrons move within the cavity 304 in response to the decrease in flux from the bar magnet 309, effectively creating eddy currents. In accordance with Lenz's law the electrons move in a way so that the induced emf which drives the eddy currents is in a direction that opposes the decrease in flux from the bar magnet 309. The result of this is that the movement of the bar magnet 309 is slowed down, with its kinetic energy and momentum being transferred to the electrons within the cavity 304.

An alternative embodiment of an apparatus 401 is shown in Figure 11. The apparatus 401 in part, is essentially identical to the apparatus 101 as previously described, in that the apparatus 401 comprises a housing 403a which is tubular in shape, the housing 403a has a cavity 404a therein, defining an enclosed volume. The housing 403a is provided with a first end cap 405a and a second end cap 407a which both seal the respective ends of the housing 403a. A bar magnet 409 is secured to the first end cap 405a at the north pole of the bar magnet 409. A cathode 417a runs through the centre of the housing 403a in an axial direction from the first end cap 405a to the second end cap 407a. The cathode 417a is configured to act as a hot cathode and can emit electrons via thermionic emission. A loop 419a is secured inside the housing 403a, so that it extends from an inner surface of the cavity 404a into the volume contained therein. The loop 419a is a small loop antenna and is connected to an electrical load (not shown).

The apparatus 401 in part is also essentially identical to the apparatus 301 as previously described. The apparatus 401 further comprises a housing 403b which is tubular in shape, the housing 403b has a cavity 404b therein, defining an enclosed volume. The housing 403b is provided with a first end cap 405b and a second end cap -22 - 407b which both seal the respective ends of the housing 403b. The south pole of the bar magnet 409 is secured to the first end cap 405b of the housing 403b.

A central anode member 418b runs through the centre of the housing 403b in an axial direction, from the first end cap 405b to the second end cap 407b. An annular cathode 417b is provided within the cavity 404b in an axial direction from the first end cap 405b to the second end cap 407b and the annular cathode 417b is spaced radially from the central anode member 418b. The housing 403b is held negative with respect to the annular cathode 417b, in order to force electrons emitted by the annular cathode 417b towards the central anode member 418b at the centre of the cavity 404b.

The annular cathode 417b is a hot cathode and is configured to emit electrons into the volume contained within the cavity 404b. In this arrangement, in use, there is an electric field between the annular cathode 417b and the central anode member 418b. A loop 419b is secured inside the housing 403b, so that it extends from an inner surface of the housing 403b into the volume contained therein. The loop 419b is a small loop antenna and is connected to an electrical load (not shown).

The arrangement is such that the magnetic field from the bar magnet 409 emanates into the cavity 404a and the cavity 404b. The magnetic field which emanates into the cavity 404a and cavity 404b is non-parallel with respect to the walls of cavity 404a and cavity 404b respectively, which extend in the axial direction. This is so that the flux density from the magnetic field through the cavity 404a and cavity 404b varies along the axis of cavity 404a and cavity 404b respectively. In this embodiment there are major components of the magnetic field directed parallel to the axial direction of the cavity 404a and cavity 404b.

A plate 411 with a first end 413 and a second end 415 is positioned adjacent the housing 403b, the bar magnet 409 and the housing 403a, such that the first end 413 of the plate 411 is adjacent the second end cap 407b of the housing 403b and the second end 415 of the plate 411 is adjacent the second end cap 407a of the housing 403a.

Effectively, the housing 403a, cavity 404a, cathode 417a and loop 419a are the same as that described with respect to apparatus 101 and the housing 403b, cavity 404b, central anode member 418b and loop 419b are the same as that described with respect to apparatus 301.

-23 -In use, the apparatus 401 operates as a combination of apparatus 101 and apparatus 301. In particular, the vortex of electrons in the cavity 404a will orbit the cathode 417a in an opposite direction to the vortex of electrons orbiting the central anode member 418b in cavity 404b. In this arrangement, the major component of the magnetic field from the vortex of electrons in the housing 403a results in a repulsive force between it and the bar magnet 409 (as shown in the apparatus 101). The major component of the magnetic field from the vortex of electrons in the housing 403b results in an attractive force between it and the bar magnetic 409 (as shown in the apparatus 301). Therefore, the overall net force on the housing 403b, bar magnet 409 and the housing 403a will be in a forward direction (which is to the left in Figure 11).

The momentum and kinetic energy from the electrons in both the vortexes are transferred to the apparatus 401. This arrangement provides the apparatus 401 with a substantially continuous propulsive force so as to act as a thruster. In this way, energy and momentum are conserved.

This arrangement of apparatus 401 may be useful as it will provide a larger forward thrust force (when being utilised as a thruster), compared to the apparatus 101 (where only a single housing 103 is used).

The apparatus 401 may also be used to generate a braking force when the apparatus 401 is moving and will operate in the same way as previously described in relation to apparatus 101 and apparatus 301. In particular, in this scenario, the apparatus 401 for example, may be free falling with a force due to gravity and is moving in the direction to the right when viewed in Figure 11.

In this case, the electrons in the housing 403a will behave as described in relation to those in the apparatus 101 (assuming there is an electric field between the cathode 417a and the housing 403a), namely the induced emf will increase the speed of the electrons in their orbit around the cathode 417a in order to increase the magnetic field strength around the vortex and to oppose the increase in incident magnetic flux, in accordance with Faraday's law and Lenz's law.

However, the electrons orbiting the central anode member 418b in housing 403b (assuming there is an electric field between the central anode member 418b and the annular cathode 417b) will experience a decrease in incident magnetic flux, as the bar magnet 409 moves away from the vortex of electrons. The induced emf will increase the -24 -speed of the electrons in their orbit around the central anode member 418b in order to increase the magnetic field strength around the vortex and to oppose the decrease in incident magnetic flux, in accordance with Faraday's law and Lenz's law.

The effect of this is that the momentum and kinetic energy of the apparatus 401 is transferred to the electrons in the two vortexes. The apparatus 401 reduces its speed, whilst the electrons in the vortexes increase their speed.

As described in previous embodiments, electrons will emit electromagnetic radiation when they are accelerated and when they collide with the respective anodes. This radiation can then be dissipated.

In this way, the kinetic energy of the apparatus 401 has been transferred to the electrons and then dissipated as heat, ultimately slowing down the apparatus 401. In this arrangement, the apparatus 401 may act as braking device.

It is also conceivable that the apparatus 401 can function as a braking device in the event when the electric field between the annular cathode 417b and the central anode member 418b is zero and the electric field between the housing 403a and the cathode 417a is zero. In this situation, electrons are being emitted from the annular cathode 417b into the volume within the cavity 404b, however the electrons are not being accelerated in an electric field towards the central anode member 418b (as previously described), because the potential difference between the housing 403b and the central anode member 418b is zero. Also, electrons are being emitted from the cathode 417a and into the volume within the cavity 404a, however the electrons are not being accelerated in an electric field towards the housing 403a (as previously described), because the potential difference between cathode 417a and the housing 403a is zero.

As before, assuming that the apparatus 401 is moving due to external forces, for example it is free falling with a force due to gravity and is moving in the direction to the right when viewed in Figure 11. The movement of the bar magnet 409 towards the electrons in the cavity 404a, increases the flux therethrough. The movement of the bar magnet 409 away from the electrons in the cavity 404b, decreases the flux therethrough.

The electrons move within the both the cavity 404a and cavity 404b in response to the change in flux from the bar magnet 409, effectively creating eddy currents. In accordance with Lenz's law the electrons move in a way so that the induced emf which -25 -drives the eddy currents is in a direction that opposes the change in flux in both cavity 404a and cavity 404b. The result of this is that the movement of the bar magnet 409 is slowed down, with its kinetic energy and momentum being transferred to the electrons within the cavity 404a and cavity 404b.

It should be noted that like components in apparatus 301 and apparatus 401 are manufactured from the same materials as described previously in reference to apparatus 101.

It is envisaged that the present invention can be scaled so that such that the acceleration and deceleration forces generated by apparatus 101, apparatus 301 and apparatus 401 acting as thrusters and braking devices are orders of magnitude greater than the prototype apparatus 201 as described above.

A number of embodiments are envisaged.

In one embodiment one or more apparatus may be mounted on a spacecraft for orbiting journeys around Earth or other planets or for journeys including interplanetary travel. An embodiment of how several apparatuses 101 could be mounted on a spacecraft 545 is shown in Figure 12.

In an embodiment, the object 10 is a spacecraft. A spacecraft is envisaged to be any vehicle which is capable of flying in outer space. For example, a satellite, space probe, space shuttle or space station.

In another embodiment the apparatuses may be used on a launch vehicle to launch the spacecraft itself from the surface of the planet into space. A configuration of booster segments may be provided, similar to conventional boosters with chemical thrusters, however the boosters could be provided with any of the apparatuses as described herein.

In an embodiment it may be that the apparatuses are configured to harvest (by generating the braking force described above) the gravitational potential energy of the booster and its kinetic energy as it falls back down to Earth (after separation from the spacecraft). The conversion of kinetic energy from the falling booster into electrical energy could charge a battery, rather than the energy simply being dissipated as heat.

In another embodiment, apparatuses operating as thrusters could assist in controlling the booster to land it safely, so that the booster can be reused. In an embodiment, -26 -batteries charged from the apparatuses operating as braking devices could power apparatuses operating as thrusters.

In an embodiment, the apparatuses operating as thrusters and braking devices may be used to control or assist control during flight of Unmanned Aerial Vehicles (UAVs). Such UAVs may include, but are not limited to, military UAVs, surveillance UAVs, delivery UAVs, visual display UAVs and consumer entertainment UAVs. In some embodiments one or more apparatus may be used with any type of flying vehicle, such as flying cars, hoverboards, jetpacks, flying boats, flying submarines and adapted aircrafts. These vehicles could be suitable for carrying people, animals and/or goods.

In some embodiments one or more apparatus may be provided as a thruster and/or braking device for underwater submersibles, boats and submarines. In an embodiment the apparatuses may be the only means of propulsion. These could be suitable for carrying people, animals and/or goods. Alternatively, these could be unmanned crafts used for surveillance, repair work and/or scientific research.

In an embodiment, the apparatuses operating as thrusters and/or braking devices may control or assist control in vehicles having wheels. It may be that the apparatus provides the driving and braking forces required to drive a vehicle. It may be that the apparatus is used together with or in place of an internal combustion engine.

In an embodiment, the apparatuses operating as thrusters and/or braking devices may control or assist control during operation of a crane. Effectively, retractable cables could be mounted on floating controlled platforms, so that various objects can be lifted, lowered and moved as desired. The floating platforms would be controlled by an arrangement of thruster and brake apparatus. This may be extremely effective in the construction and oil well industry and in situations when conventional cranes are not usable.

In an embodiment, the apparatuses operating as thrusters and/or braking devices may act as stabilisers, to control or assist control on aircrafts for example, in the event of turbulence. Other motion suppressor applications are envisaged, for example use as a damper or braking device in wind, wave and tidal powered generators.

In an embodiment, apparatuses operating as thrusters and/or braking devices may be used to control or assist in the control of toys, models and novelty gifts. The use of the apparatuses may make it appear as though they can move along the ground or -27 -that fly or float in mid-air. Due to the nature of the apparatus, it is not necessarily apparent as to what is propelling the desired object, this is compared to a visible exhaust from a chemical thruster for example. This mysterious effect could be appealing to the observer.

In an embodiment, the apparatuses operating as thrusters and/or braking devices could control or assist controlling trays of canapes, which are provided with the apparatuses. The trays may be controlled remotely or which may incorporate self-driving technology, so as to move between people to offer the contents being carried. Upon removal of the contents, the trays can fly back to a refilling station.

In an embodiment, the apparatuses operating as thrusters and/or braking devices may be configured to control or assist control of a target. The target could move around as one attempts to hit it with a stick in order to improve one's coordination skills. In an embodiment, it could be that a plurality of apparatuses are manufactured from a single block of material or secured together so as to form an array of apparatuses.

The array could function as an array or thrusters, braking devices or a combination of both.

In an embodiment, the apparatus could control or assist in the control of a strong magnetic field which it generates. The shape of the magnetic field may be controllable and the apparatus could be configured so that the magnetic field shape and strength it generates encompasses at least a portion of an object (e.g. a spacecraft). This could then protect the spacecraft from charged particles colliding with it, which would otherwise risk damaging the equipment and crew within the spacecraft and the body of the spacecraft itself. In this event the magnetic field would deflect oncoming charged particles into a direction such that the particles would not come into contact with the spacecraft and its contents therein.

Various modifications to the embodiment described are envisaged. In particular it is conceivable that the bar magnet could be orientated in an opposite direction. The apparatus will operate in the same way, however the vortex of electrons will travel in a reversed direction (clockwise in the view shown in Figure 2).

It may be that the bar magnet is replaced with an electromagnet. In this way, the strength of the magnetic field can be adjusted in addition to the electric field strength between the cathode and the anode and the rate of electron emission from the cathode.

-28 -This may be useful in order to configure the apparatus for a particular use. It may be that the radius of the obit of the electrons can be adjusted in this way. It could be that the polarity of the electromagnet could be swapped and utilised to provide desired control over the apparatus.

It may be that multiple separate cathodes can be connected together to replace a single cathode. It could be that the separate cathodes are configured to emit electrons into the cavity separately from each other and at different rates. This may be as a result of different levels of current being driven through the different cathodes. The potential difference between the cathodes and the anode may be varied from cathode to cathode.

This may allow the vortex of electrons about individual cathodes to be controlled separately of other vortexes of electrons about other cathodes.

This aspect of multiple stacked cathodes may be advantageous as it could allow the apparatus to be fine tuned so as to generate desired forces. The fine tuning of electron vortex behaviour may provide the ability for the apparatus to compensate for magnetic flux through a particular section of the cavity originating from neighbouring vortexes. This may allow longer apparatuses to be constructed, which could generate larger forces.

It could be that the housing/central anode member and the cathode/annular cathode are configured in a way so that their functions are interchangeable. For example, it would be useful if a central cathode arrangement could be remotely swapped over into a central anode arrangement and vice versa, without having to manually swap over components within the apparatus. This may be advantageous as it could provide control over the direction of thrust on the apparatus. It may provide control over the most effective direction of the apparatus when it is being used as a braking device.

It could be that the unwanted electromagnetic radiation, which is removed via the loop, is then channelled into a reclaimer and utilised. For example, a half wave or a full wave rectifier circuit could be used to convert the alternating current induced in the loop into direct current. The direct current could then be channelled back into a suitable location in the power source circuitry. It may be that a coaxial cable is used to connect the loop 119 and the rectifier circuit. In the prototype, a coaxial cable could be directly connected to the antenna and a rectifier circuit in order to reclaim energy from the microwaves emitted from said antenna.

-29 -Alternately, the loop is connected to an electrical load and thermocouples are embedded in the load (load cell). The electrical energy in the loop is dissipated into the load in the form of heat. This dissipated heat is converted back into electrical energy via the thermocouples. This electrical energy could be utilised as previously stated.

Alternatively, thermocouples could be embedded in the electrical load of the prototype (e.g. block of polymer resin mixed with black copper oxide powder) and the heat dissipated into the load from the microwaves emitted by the antenna, is converted into electrical energy. This electrical energy could be utilised as previously stated.

It may be that the unwanted electromagnetic radiation is used to heat a fluid to produce a vapour, e.g. water vapour. This vapour in turn could spin a turbine or dynamo to generate electrical energy. This electrical energy could be utilised as previously stated.

A cold cathode, emitting electrons by the field effect, could be used in place of the hot cathode. It may be that such a cathode is manufactured from graphite or graphene or copper coated with graphene in order to provide suitable emission properties.

It could be that a hot cathode is used, which is specifically heated indirectly in order to emit electrons.

Claims

-30 -Claims: 1. An apparatus for generating a force, the apparatus comprising: a housing having a cavity therein; a magnet adjacent the housing, the magnet and housing arranged so that, in use, the cavity contains a magnetic field from the magnet, magnetic field lines within the cavity comprising non-parallel magnetic field lines; a cathode capable of emitting electrons into the cavity; and an anode, the arrangement being such that, in use, the cathode emits electrons into the cavity and the electrons are deflected by the magnetic field from the magnet, such that a force acts between the magnetic field from the magnet and a magnetic field from the electrons and kinetic energy is transferred between the apparatus and the electrons.
2. An apparatus as claimed in Claim 1, wherein the cavity is sealed so as to contain a closed volume therein.
3. An apparatus as claimed in Claim 2, wherein the housing is provided with a first end cap and a second end cap, so as to seal the cavity.
4. An apparatus as claimed in Claim 2 or 3, wherein the cavity is under vacuum.
5. An apparatus as claimed in any preceding claims, wherein one of the cathode and anode extends substantially centrally in an axial direction through the cavity.
6. An apparatus as claimed in Claim 5, further comprising a power source for maintaining a potential difference between the anode and the cathode so that, in use, there is an electric field between the cathode and the anode, the electric field and magnetic field from the magnet being such that, when the cathode is activated to emit electrons into the cavity, the electrons exhibit a vortex like flow -31 -about one of the cathode and anode which extends substantially centrally in an axial direction through the cavity.
7. An apparatus as claimed in Claim 6, adapted so that, in use, in the cavity, the magnetic field of the magnet comprises a component having a direction orthogonal to a direction of a component of the electric field.
8. An apparatus as claimed in Claim 6 or 7, adapted so that, in use, at least some of said electrons in said vortex perform an orbit within said cavity.
9. An apparatus as claimed in Claim 6 or 7, adapted so that, in use, the vortex like flow of electrons generates a magnetic field, which interacts with the magnetic field of the magnet to generate the force on the apparatus.
10. An apparatus as claimed in Claim 9, adapted so that, in use, in the cavity, the magnetic field of the magnet comprises a component having a direction parallel to a direction of a component of the magnetic field generated by the vortex like flow of electrons.
11. An apparatus as claimed in Claim 9 or 10, adapted so that, in use, when said apparatus is moving, the non-parallel magnetic field lines in the cavity induce an electromotive force on said electrons in said vortex-like flow, which electromotive force tends to accelerate or decelerate said electrons depending on the direction of movement of the apparatus relative to said vortex-like flow of electrons.
12. An apparatus as claimed in Claim 11, adapted so that, in use, the direction of the force on the apparatus and the direction of the electromotive force are substantially perpendicular to one another.
13. An apparatus as claimed in Claim 9, adapted so that, in use, the force on the apparatus is a result of the interaction between the magnetic field from the magnet and the magnetic field from the vortex like flow of electrons either accelerates or decelerates the apparatus.
-32 - 14. An apparatus as claimed in any preceding claim, adapted so that, in use, the transfer of kinetic energy from the electrons to the apparatus, accelerates the apparatus.
15. An apparatus as claimed in any of Claims 1 to 13, adapted so that, in use, the transfer of kinetic energy from the apparatus to the electrons, decelerates the apparatus.
16. An apparatus as claimed in Claim 5, wherein the cathode extends substantially centrally in an axial direction through the cavity and the anode is positioned at a radial distance from the cathode.
17. An apparatus as claimed in Claim 16, adapted so that, in use, the force between the magnetic field from the magnet and the magnetic field from the vortex like flow of electrons is repulsive.
18. An apparatus as claimed in Claim 5, wherein the anode extends substantially centrally in an axial direction through the cavity and the cathode is positioned at a radial distance from the anode.
19. An apparatus as claimed in Claim 18, adapted so that, in use, the force between the magnetic field from the magnet and the magnetic field from the vortex like flow of electrons is attractive.
20. An apparatus as claimed in any preceding claim, wherein the apparatus further comprises a loop provided within the cavity, so that in use, electromagnetic radiation within the cavity induces a current in said loop.
21. An apparatus as claimed in Claim 20, adapted so that, in use, the energy resulting from the induced current in said loop is reclaimed.
-33 - 22. An apparatus as claimed in any preceding claim, wherein the apparatus further comprises a plate positioned relative to the housing and magnet so that in use the magnetic field is returned to complete a magnetic circuit.
23. An apparatus comprising an apparatus according to Claim 16, fixed to a first pole of a magnet and a second apparatus according to Claim 18, fixed to the opposing pole of said magnet.
24. A device, such as a vehicle, a rocket booster, a spacecraft or a space station comprising an apparatus in accordance with any of Claims 1 to 23.
25. A method of generating a force on an apparatus, the method comprising the following steps: providing an apparatus in accordance with Claim 1; and activating the cathode to emit electrons into the cavity, for said electrons to be deflected by the magnetic field from the magnet, such that a force acts between the magnetic field from the magnet and a magnetic field from the electrons and kinetic energy is transferred between the apparatus and the electrons.