WO2002046611A1

WO2002046611A1 - A device for generating thrust

Info

Publication number: WO2002046611A1
Application number: PCT/GB2001/005428
Authority: WO
Inventors: Remi Oseri Cornwall
Original assignee: Remi Oseri Cornwall
Priority date: 2000-12-08
Filing date: 2001-12-07
Publication date: 2002-06-13
Also published as: GB0030060D0; AU2002222143A1

Abstract

A device for generating linear thrust, the device comprising: a drive element; and a field generator to produce an asymmetric distribution of time-varying electric and magnetic fields around the drive element such that an overall Poynting vector exists in the region of the drive element, thereby giving rise to a net flow of energy in a first direction.

Description

Conveniently, the cross-section of the inductor or a capacitor is substantially in the form of a polar plot of the function r = l+cosh(θ).

Advantageously, the drive element is an inductor, further comprising a shunt inductor of greater inductance than the drive element, the shunt inductor being placed in parallel with the drive element.

Preferably, recovery means are provided to recover a portion of the energy associated with a field around the drive element.

Conveniently, the drive element is an inductor, and wherein the recovery means comprise a coil of opposite polarity to the drive element.

Advantageously, the drive element is an inductor, and is formed from a substantially non-conductive, high permeability material, in order to increase the magnitude of the magnetic field in the region thereof.

Preferably, the drive element is a capacitor, and wherein a high permittivity, substantially non-conductive dielectric is provided, in order to increase the magnitude of the electric field in the region of the drive element.

Conveniently, the drive element comprises a long chain molecule or a molecular matrix comprising a plurality of asymmetric charge distributions.

Advantageously, the asymmetric charge distributions are associated with individual atoms or ions in the long chain molecule or a molecular matrix. 3 Preferably, the field generator comprises means to generate radiation in a direction parallel to the axis of polarisation of at least some of the asymmetric charge distributions.

Conveniently, the net flow of energy in the first direction gives rise to a corresponding thrust in a direction opposite to the first direction.

Another aspect of the present invention provides a vehicle having a drive mechanism comprising a device according to any preceding claim.

A further aspect of the present invention provides a method of generating linear thrust, the method comprising the step of generating an asymmetric distribution of time-varying electric and magnetic fields around a drive element such that an overall Poynting vector exists in the region of the drive element, thereby giving rise to a net flow of energy in a first direction.

Advantageously, the drive element comprises an inductor or a capacitor, the cross-section of which has at least an axis about which the cross-section is asymmetric.

Preferably, the step of generating an asymmetric distribution of varying electric and magnetic fields around the drive element comprises the steps of sequentially charging and discharging the inductor or capacitor.

Conveniently, the inductor or capacitor has a cross-section substantially in the form of a polar plot of the function r = l+cosh(θ).

Advantageously, the drive element comprises an inductor, the method further comprising the steps of providing a shunt inductor of greater inductance 4 than the drive element, and placing the shunt inductor in parallel with the drive element.

Preferably, the method further comprises the step of recovering a portion of the energy associated with a field around the drive element.

Conveniently, the drive element comprises an inductor, and wherein the step of recovering a portion of the energy associated with a field around the drive element comprises the step of providing a coil of opposite polarity to the drive element.

Advantageously, the drive element comprises an inductor, and is formed from a substantially non-conductive, high permeability material, in order to increase the magnitude of the magnetic field in the region thereof.

Preferably, a high permittivity, substantially non-conductive dielectric is provided, in order to increase the magnitude of the electric field in the region of the drive element.

Advantageously, the asymmetric charge distributions are associated with individual atoms or ions in the long chain molecule or a molecular matrix.

Preferably, the step of generating an asymmetric distribution of time- varying electric and magnetic fields around the drive element comprises the step of generating radiation in a direction parallel to the axis of polarisation of at least some of the asymmetric charge distributions. Conveniently, the net flow of energy in the first direction gives rise to a corresponding thrust in a direction opposite to the first direction.

In order that the present invention may be more readily understood, embodiments thereof will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a schematic representation of Feynman's disk;

Figure 2 shows a conducting loop;

Figure 3 shows the directions of the electric and magnetic fields and Poynting vectors in the vicinity of a capacitor and an inductor;

Figure 4 shows the cross-section of an inductor suitable for use with the present invention;

Figure 5 gives the listing of a computer program suitable for performing an integration relating to the field momentum in the vicinity of the inductor of Figure 4;

Figure 6 is a schematic representation of a molecular matrix suitable for use with the present invention;

Figure 7 shows a circuit suitable for use with the present invention; and

Figure 8 shows an electronic switch suitable for use with the present invention. Turning firstly to Figure 1, a device 1 known as a Feynman disk is shown. The device 1 comprises a disk 2, which is formed from plastic or another insulating material, and is provided with a number of charged metal spheres 3 distributed near the rim thereof. The disk 2 is supported on an elongate spindle 4 passing through the centre thereof, perpendicular to the plane of the disk 2, and the disk 2 is free to rotate about the axis of the spindle 4.

On one surface of the disk 2, a coil 5 of conducting wire is placed around the spindle 4, and a battery 6 or other current source drives a current around the coil 5.

The flow of electromagnetic energy per unit area is given by the Poynting vector,

ε₀c Ε xB

and clearly in the case of the device depicted in Figure 1 the net flow of electromagnetic energy will be in one direction around the spindle 4, i.e. the direction in which current is driven therearound.

As dictated by the relation E=mc², energy is equivalent to mass, and hence a flow of energy will be associated with a momentum in the direction of the flow of energy. The momentum density in the case of a flow of electromagnetic energy is given by

If the current flowing through the coil is suddenly switched off, an electromagnetic field acts symmetrically and tangentially to the charged spheres, and this should generate a torque around the spindle 4. Observation supports this theory, and indeed the disk 2 will begin to rotate upon a sudden switching off of the current in the coil 5. This experiment could be conducted in vacuo, and no violation of conservation of momentum is committed since the mechanical angular momentum imparted to the disk 2 is equal and opposite to the angular momentum associated with the flow of electromagnetic energy around the coil 5 prior to the current therethrough being switched off.

This well known Feynman disk experiment illustrates the momentum of an electromagnetic field (R. P. Feynman, R. B. Leighton and M. Sands, The Feynman Lectures on Physics, Addison Wesley, Reading, MA, 1964,Nol II, pi 7-5). This experiment was performed by G. Graham and D. G. Lahoz "Observation of static electromagnetic angular momentum in vacuo ", Nature 285, 154 (1980) amongst others.

It has been proposed to utilise the momentum associated with a flow of energy to impart a linear thrust to an object. Devices devised for this purpose are so-called ExH or ExB devices. It can be shown that, in the case of static fields, a hidden mechanical momentum prohibits these devices from imparting a linear thrust. A full treatment of this hidden momentum can be found in V. Hnizdo "Hidden momentum of a relativistic fluid carrying current in an external field", Am. J. Phys. 65, 92 (1997). As discussed above, there is little or no matter in space against which a spacecraft may exert a force to alter the 8 momentum of the craft, and the ability to generate a thrust by balancing the momentum of a craft against that of a flow of energy would be invaluable. However, thus far efforts to provide a device capable of generating such a thrust have proved unsuccessful.

Turning to Figure 2, a flow of a positively charged incompressible fluid 7 clockwise around a loop 8 of cross-sectional area a is shown. The loop 8 is provided in a region of constant uniform electric field E, directed downwards in Figure 2.

In this static situation, the momentum associated with the flow of the fluid 7 is given by

and in this case

where I is the current flowing in the loop 8 and h and w are the vertical and horizontal dimensions of the loop 8 respectively. Hence, it can be seen that the flow of the fluid 7 around the loop 8 in the presence of the electric field E is associated with a non-zero overall momentum, which is directed to the right in Figure 2. 9

However, the fluid 7 flowing through the bottom limb 9 of the loop 8 (as seen in Figure 2) is at a higher pressure, due to the action of the electric field. As mentioned above, the flow of the fluid 7 is clockwise, and hence the greater pressure of the fluid 7 flowing through the bottom limb 9 of the loop 8 gives rise to a net energy flow to the left, which is given by

where v is the velocity of the fluid 7 and p is the charge density of the fluid 7.

Using the relation s=gc set out above, it can be seen that the momentum density associated with the net flow of energy to the left is given by

Saw IEhw

Pmech = s^a = —r = —r- c c

where aw is the volume of the bottom limb 9 of the loop 8. Comparing this result with that for the overall momentum of the fluid flow calculated above, it can be seen that the two momenta are equal and opposite. Hence, the flow of the fluid 7 around the loop 8 gives rise to a zero overall momentum.

In order to generate a non-zero linear momentum from an energy flow in a situation of this type, the symmetry described above, in which the bottom limb 9 of the loop 8 experiences a higher pressure, must be broken. This may be achieved if the electric field circulates around the magnetic field, and there is no opposing electric field arising from Ohm effects. This is possible if time varying fields and non-conductive media are employed, and this arrangement 10 corresponds to an inductor. Alternatively, a capacitor may be used, and in this case the magnetic field circulates around the electric field. In preferred embodiments of the present invention, the cycling frequency of the time- varying fields is in excess of 100kHz.

In the case of an inductor, the use of a substantially non-conductive, high permeability material, such as a ferrite, may be used to increase the magnetic field in the region of the inductor. In the case of the capacitor, a substantially non-conductive high permittivity dielectric may be provided, in order to increase the magnitude of the electric field in the region of the capacitor.

Turning to Figure 3, the direction of the electric and magnetic fields and of the Poynting vector, during the charge and discharge of a large circular capacitor, as well as around a long inductor of circular cross-section, are shown. Clearly, in such a symmetrical situation, the net Poynting vector (and hence the momentum associated with the Poynting vector) will be zero. However, it will now be demonstrated that an inductor or capacitor not displaying such symmetry may give rise to a net Poynting vector, and hence to a net linear momentum.

Although at first glance it might appear that such a result would give rise to a violation of the law of conservation of momentum, this is not so, as the inductor or capacitor exerts a force on the mass-energy present as a result of fluctuations in the quantum ground state of the electromagnetic field surrounding the inductor or capacitor. The energy-time uncertainty relation ΔEΔt < h (where h is equal to Planck's constant divided by 2π) dictates that, even in vacuo, virtual particles are constantly brought into existence and h destroyed again, although this process must occur within a timescale of

ΔE 11 where E is the energy associated with a particle. Such particles are commonly known as "virtual particles". It has been estimated that the mass density associated with these ground state fluctuations is of the order of 10⁹³g/cm³, although this is isotropic (R. P. Feynman and A. R. Hibbs, Quantum Mechanics and Path Integrals, McGraw-Hill, New York 1965).

An arbitrary long inductor will now be considered, the axis of which is oriented along the z-axis. The magnetic field associated with the inductor can be calculated using the Biot-Savart law:

The magnetic field at point 1 is calculated around a current loop, having elements ds₂ which are separated by rι₂. For the above-described case of a long solenoid, we only get a field in the z direction:

where 'C represents an arbitrary closed curve around which the line integral is performed. The electromagnetic momentum is given by: 12

For the purposes of a long inductor, this reduces to:

_Pem = ε_Q j{E_yB_zi + E_xB }iV

This can be further reduced by symmetry if the inductor is given a cross- sectional shape as shown in Figure 4, which is a polar plot of r = l+cosh(θ). The components of the electromagnetic momentum will cancel to give:

It is aimed to show sufficiency by calculating this integral over the dA area element only. E_y may be calculated as a function of B_z by Maxwell's curl equation for the magnetic field in a non-conductive media (note that differentiation is performed with respect to xi):

d

E = c² (jB_Mdt) dx_ϊ

Substituting the expression that was previously derived for B_z and making the appropriate substitutions:

x_x = (l + )saιθ_x]fiθ_x y_x = (l + )cos#_y μθ_y x₂

y₂ = (l + cosh θ₂ )sin#₂ => dy = [sinh#₂sin#₂ + (l + cosh#₂ )cos#₂ βθ₂

The integration may then be performed, and it can be seen that the result is non-zero: 13

This integration needs to be performed numerically, and it is found that the result is negative for the shape shown in figure 4. Hence, it will be appreciated that there is a net flow of energy to the left (as seen in Figure 4), and therefore a net flow of momentum in this direction will be associated with the flow of energy. In order for momentum to be conserved, a mechanical momentum to the right must be imparted to the inductor itself, and hence to a spacecraft in which the inductor may be situated.

Figure 5 contains a listing of a Matlab™ suitable for performing this integration, and this program reads very much like a 'C listing. The exact shape of the inductor, and hence the mechanical momentum that can be imparted thereby, can be optimised by analytical or numerical techniques. However, what is essential is a bulbous, elongated but symmetrical structure, an example of which is shown in Figure 4. The cross section of the inductor has at least one axis about which the cross-section in substantially asymmetric. It is envisaged that several different shapes may prove effective in providing a net linear thrust in the above-described manner.

Of course, the above considerations relating to cross-sectional shape apply equally to the shape of a capacitor, which may also be used as a drive element in embodiments of the present invention.

As described above, varying fields must be established to break the symmetry of the arrangement depicted in Figure 2, and in use of advantageous embodiments of the present invention an inductor of the type described above will be alternately charged and discharged. 14

The thrust imparted to the inductor will be in the same direction during the charge and discharge phases of each cycle, and this can be seen from the above equation defining P_β , since during discharge phase the polarities of the

E_y and B_z components are reversed over the integration area as compared to the charge phase.

The motive force provided by an arrangement such as that described above is proportional to the energy asymmetry (i.e. the magnitude of the overall energy flow) and to the frequency with which the current is cycled. This scheme is not to be confused with photonic propulsion, where radiative pressure provides a force. Energy radiated in devices embodying the present invention is minuscule compared to the field energy flowing through the system as it cycles. In photonic drive systems, the flow of energy supplied to the system is employed in producing the required fields, the kinetic energy of the system and the radiation. The present invention exploits a different mechanism of actually pushing against the mass-energy of the surrounding electromagnetic field's quantum ground state.

It will now be shown that forces arising from the radiation are minuscule (indeed, the device is much below wavelength size so antenna efficiency is very low anyway) compared to the momentum of the flow of electromagnetic energy needed to set up the fields in a device embodying the present invention. The asymmetry in the flow of electromagnetic energy to the device will be modelled by a number k, that lies between 0 and 1. The fields will be considered far from the device, to avoid the necessity to consider complicated near-field effects, and this is perfectly acceptable in terms of energy conservation. Consider an 15 asymmetric capacitor which, from a large distance, looks just like a dipole. The magnitude of the electric far-field from this dipole is given by:

In the far-field the power output is given by E /e₀c. In the limiting case of the acceleration of the charges tending to zero, the radiated energy also tends to zero, but the same energy must be invested in setting up the device's fields. A certain proportion of this energy, independent of frequency k, resulting from the asymmetric field distribution will impart kinetic energy. Thus, the propulsion is not provided by radiation-pressure.

The inductor form of the device of the present invention benefits from the high energy density of the magnetic field, compared to that of the electric field. Nethertheless, an asymmetric capacitor confers additional benefits at high frequency.

Turning to Figure 6, an alternative arrangement embodying the present invention comprises a long chain molecule or matrix with an asymmetric charge distribution, that is excited by very high frequency radiation substantially parallel to the axis of molecular polarisation. The radiation gives rise to a vibrational mode in the molecule or matrix, the effect of which is to alternately compress and expand the molecule or matrix in the y direction (as shown). The magnetic field circulates around the displacement current, and the electric field is perpendicular to the plane of the elongated molecules, in counter-symmetry to the asymmetric inductor case. 16

Whether the drive element employed to impart a linear thrust is an inductor, a capacitor or a molecular arrangement, power must be effectively distributed to the active portions of the element, without excessive fields existing in associated power generation and storage equipment, thereby creating a counter momentum acting against that produced by the element. This may be easily achieved by ensuring that such power generation and storage devices display circular symmetry.

Only a small portion of the total field energy of the device is consumed in imparting kinetic energy to the device. Regenerative re-cycling of energy improves the efficiency of the device. Figure 7 shows a circuit for regenerative field excitation of an asymmetric inductor, although a skilled person will readily appreciate similar arrangements for use with the capacitor or molecular embodiments of the present invention. In the circuit, a power source P is placed in parallel with a drive inductor L_l5 L₂, a first switch Sp being placed adjacent the power source. The drive inductor Li, L₂ is to be used to generate the required linear thrust.

High frequency switching of voltage sources into inductors is problematic, since one must aim to provide the circuit with a low time constant. A high voltage power supply is a possibility, but in practice very little end use power goes to the actual voltage source, and clearly such an arrangement is inefficient. Similarly, active current sources are also inefficient.

A preferable solution is to shunt a storage inductor L_s, whose current has already been set up using the switch S_P and battery (as shown in Figure 7), in parallel with the power source P and the drive inductor Li, L₂. The inductance of the storage inductor L_s is larger than the inductance of the drive inductor Li, L₂. Inevitably, not all of the field energy generates kinetic energy on each cycle, 17 and advantageously a portion of this energy is recovered by a regenerative technique employing an opposite polarity coil. A pair of further switches Si and S₂ in Figure 7 make this possible, the further switches Si and S₂ are connected to a central point of the drive inductor Li, L₂ and to an end of the drive inductor Li, L₂ respectively, and are placed in parallel to one another, both being ultimately connected to the power source P.

The operation of the device is as follows. Firstly, the storage inductor Ls (which, it should be noted, is of circular cross-section) is charged via switch Sp. Other switches are open at this point. Next, the required field is set up, and this is achieved by closing switch Si, while the other switches are open. Finally, the field is switched off and energy is returned to the storage inductor L_s, by the closing of switch S₂ while the other switches are open.

To minimise stray capacitance, well-spaced windings can be wound around the drive inductor Li, L₂. A typical technique in this regard is to separate turns by nylon wire. Nested layers may also be separated by nylon sheet. The skin effect of the windings can be minimised by use of Liftz wire, which increases power efficiency. To reduce the current requirements, a high permeability but low conductivity core for the inductor, such as ferrite, is preferably employed. The upper frequency of operation is limited by the losses in the core, and by the performance of the switches.

A technique for making fast, high-voltage, high-power switches will now be described with reference to Figure 8, in which two inductors L_a and L_b are shown in series with one another.

Current flow from the first inductor L_a (corresponding to a storage inductor) can be blocked by placing an even greater inductor (i.e. the second 18 inductor L_b) in series therewith. Thus, a switch is provided whose inductance can be varied.

In the arrangement of Figure 8, in which two inductors L_a and L_b are effectively provided, the first inductor L_a is considered as being composed of two coils of opposing polarity, there being a slight difference in the number of turns on each coil. This arrangement ensures good flux linkage for a coil with only a few turns. Winding on a toroid leads to near perfect linkage, but for ease of analysis a long solenoid is considered. The switch on the step-down side sees only a low voltage, and can be made from a field effect transistor.

To consider how the inductance of this arrangement varies, consider

B_T = t-(N₁i₁ +i₂(N₂ -N₃))

where

B_τ is the total flux density through the coils; " μ is permeability; 1 is the length of the coils; N number of turns; and i is current.

By Faraday's Law,

Substituting i₂ from the above expression for B_τ into this equation gives 19

where ΔΝ is the difference in the number of turns on the coils. This first order differential equation can be solved as

The inductance of coil 1 is

I R 1 _₍

\ - _e ι*^Aw t, /

The flux is banished from the core, leading to a very low inductance. After five time constants, the flux is effectively at its full normal value (in practice, it will be at 99% thereof). The parameters of the arrangement are set so that this window is longer than the cycle time of the circuit using the switch.

It will be understood that the present invention provides an effective an useful manner of generating a linear thrust, which is likely to find application in the field of travel in low-pressure environments.

In the present specification "comprises" means "includes or consists of and "comprising" means "including or consisting of.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in 20 terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

21CLAIMS

1. A device for generating linear thrust, the device comprising: a drive element; and a field generator to produce an asymmetric distribution of time-varying electric and magnetic fields around the drive element such that an overall Poynting vector exists in the region of the drive element, thereby giving rise to a net flow of energy in a first direction.

2. A device according to Claim 1, wherein the drive element comprises an inductor or a capacitor, the cross-section of which has at least an axis about which the cross-section is asymmetric.

3. A device according to Claim 2, wherein the field generation means comprise means to sequentially charge and discharge the inductor or capacitor.

4. A device according to Claim 2 or 3, wherein the cross-section of the inductor or a capacitor is substantially in the form of a polar plot of the function r = l+cosh(θ).

5. A device according to any preceding claim, wherein the drive element is an inductor, further comprising a shunt inductor of greater inductance than the drive element, the shunt inductor being placed in parallel with the drive element.

6. A device according to any preceding claim, wherein recovery means are provided to recover a portion of the energy associated with a field around the drive element. 22

7. A device according to Claim 6, wherein the drive element is an inductor, and wherein the recovery means comprise a coil of opposite polarity to the drive element.

8. A device according to any preceding claim, wherein the drive element is an inductor, and is formed from a substantially non-conductive, high permeability material, in order to increase the magnitude of the magnetic field in the region thereof.

9. A device according to any one of claims 1 to 4, wherein the drive element is a capacitor, and wherein a high permittivity, substantially non- conductive dielectric is provided, in order to increase the magnitude of the electric field in the region of the drive element.

10. A device according to Claim 1, wherein the drive element comprises a long chain molecule or a molecular matrix comprising a plurality of asymmetric charge distributions.

11. A device according to Claim 10, wherein the asymmetric charge distributions are associated with individual atoms or ions in the long chain molecule or a molecular matrix.

12. A device according to Claim 10 or 11, wherein the field generator comprises means to generate radiation in a direction parallel to the axis of polarisation of at least some of the asymmetric charge distributions. 23

13. A device according to any preceding claim, wherein the net flow of energy in the first direction gives rise to a corresponding thrust in a direction opposite to the first direction.

14. A vehicle having a drive mechanism comprising a device according to any preceding claim.

15. A method of generating linear thrust, the method comprising the step of generating an asymmetric distribution of time-varying electric and magnetic fields around a drive element such that an overall Poynting vector exists in the region of the drive element, thereby giving rise to a net flow of energy in a first direction.

16. A method according to Claim 15, wherein the drive element comprises an inductor or a capacitor, the cross-section of which has at least an axis about which the cross-section is asymmetric.

17. A method according to Claim 16, wherein the step of generating an asymmetric distribution of varying electric and magnetic fields around the drive element comprises the steps of sequentially charging and discharging the inductor or capacitor.

18. A method according to Claim 16 or 17, wherein the inductor or capacitor has a cross-section substantially in the form of a polar plot of the function r = l+cosh(θ).

19. A method according to any one of Claims 15 to 18, wherein the drive element comprises an inductor, the method further comprising the steps of 24 providing a shunt inductor of greater inductance than the drive element, and placing the shunt inductor in parallel with the drive element.

20. A method according to any one of Claims 15 to 19, further comprising the step of recovering a portion of the energy associated with a field around the drive element.

21. A method according to Claim 20, wherein the drive element comprises an inductor, and wherein the step of recovering a portion of the energy associated with a field around the drive element comprises the step of providing a coil of opposite polarity to the drive element.

22. A method according to any one of Claims 15 to 21, wherein the drive element comprises an inductor, and is formed from a substantially non- conductive, high permeability material, in order to increase the magnitude of the magnetic field in the region thereof.

23. A method according to any one of Claims 15 to 18, and wherein a high permittivity, substantially non-conductive dielectric is provided, in order to increase the magnitude of the electric field in the region of the drive element.

24. A method according to Claim 15, wherein the drive element comprises a long chain molecule or a molecular matrix comprising a plurality of asymmetric charge distributions.

25. A method according to Claim 24, wherein the asymmetric charge distributions are associated with individual atoms or ions in the long chain molecule or a molecular matrix. 25

26. A method according to Claim 24 or 25, wherein the step of generating an asymmetric distribution of time-varying electric and magnetic fields around the drive element comprises the step of generating radiation in a direction parallel to the axis of polarisation of at least some of the asymmetric charge distributions.

27. A method according to any one of Claims 15 to 26, wherein the net flow of energy in the first direction gives rise to a corresponding thrust in a direction opposite to the first direction.

28. A device substantially as hereinbefore described, with reference to Figures 4 to 8 of the accompanying drawings.

29. A method substantially as hereinbefore described, with reference to Figures 4 to 8 of the accompanying drawings.

30. Any novel feature or combination of features disclosed herein.