Electric Currents, Magnetic Fields, Magnetic Pulses, and Electromagnetic Propulsion
| Scientific Paper | |
|---|---|
| Title | Electric Currents, Magnetic Fields, Magnetic Pulses, and Electromagnetic Propulsion |
| Read in full | Link to paper |
| Author(s) | John R Warfield |
| Keywords | Electric Currents, Magnetic Fields, Magnetic Pulses, Electromagnetic Propulsion |
| Published | 2008 |
| No. of pages | 12 |
Read the full paper here
This page and Electric Currents, Magnetic Fields, Magnetic Pulses and Electromagnetic Propulsion describe the same twelve-page paper, archived under two title variants differing only by a comma.
Abstract
A single circular loop conductor [ring] with its current induces a magnetic field, not only surrounding the ring but also within the substance of the ring. Subsequently, that portion of the magnetic field, which is located within the body of the ring, interacts with its own current to produce Lorentz forces. Electromagnetic propulsive forces are produced from this process. However, these forces are either blocked by the intact structure of the ring, or they are symmetrically oriented in opposing directions. As such, these later forces counteract each other. Essentially, all the forces are balanced; consequently there is no propulsion of the ring. However, if a directed magnetic pulse [magnetic flux compression producers] distorts the magnetic field relative to one side of the plane of the ring, then for the duration of this pulse, there will be within the ring some Lorentz forces that are neither blocked by its physical structure nor an-nulled by opposing symmetrical forces. Accordingly, these forces are unbalanced. As a result, there will be electromagnetic propulsion of the ring along its axis.
Overview
John R. Warfield, a physician writing from Scottsdale, Arizona, proposes a scheme for propelling a conducting ring through space with no propellant at all. The paper is unusual in method: it contains no equations, and its entire argument is carried by six labelled diagrams presented in sequence, each one building the geometrical picture needed for the next. Warfield states his three premises at the outset — that a current in a conductor induces a magnetic field not only around the conductor but within its own substance; that this interior portion of the field interacts with the same current to produce Lorentz forces inside the conductor; and that magnetic flux compression technology can project a powerful directed magnetic pulse "analogous to a gun."
The claim that follows is that a current-carrying ring is normally in perfect internal force balance and therefore does not move, but that a directed magnetic pulse fired from the centre of the ring toward one side of its plane destroys the mirror symmetry of the interior field for the duration of the pulse, leaving a residue of unbalanced Lorentz forces which propel the ring along its axis. Where mainstream propulsion physics requires that thrust be paid for by expelling something — mass, or at minimum field momentum — Warfield argues explicitly that no such payment is required here: the reaction on the pulse generator and the thrust on the ring "do not necessarily have to counteract one other, nor are they unavoidably equal to each other." That assertion, rather than any of the diagrams, is the paper's load-bearing step.
The six diagrams
Diagrams 1 to 3: straight conductors
Diagram 1 is a single straight wire with its current flowing into the page. The induced field is circular and exists inside the wire as well as outside it; the interior field crossed with the wire's own current gives Lorentz forces directed symmetrically inward toward the wire's axis, all around the circumference. Warfield is careful to say what follows: the forces are balanced, so "there is no motion." He also notes that he will resolve the forces into x and y components for ease of exposition even though the true pattern is radial.
Diagram 2 places two straight wires side by side with currents in the same direction. The two fields superpose into "one overall modified field." Within each wire the interior flux density is now greater laterally than medially, so the Lorentz force directed medially exceeds the one directed laterally, and each wire is left with a net medial force: the wires move together. Diagram 3 reverses one current, the asymmetry inverts, and the wires move apart. These recover the textbook Ampère result for parallel currents, though by a nonstandard route — Warfield locates the force wholly inside the conductors, stressing that "outside the substance of the wires in the region of the interacting magnetic fields, there is no force." He dismisses both cases as propulsion: once the wires touch, or once they separate far enough for the fields to stop interacting, the motion ends.
Diagram 4: the ring in balance
Diagram 4 introduces the ring, which Warfield defines as a single circular loop conductor. The field is the classical loop field, and inside the body of the ring the flux density is greater on the inner side than the outer side. The result, "throughout 360 degrees," is a residual Lorentz force directed radially outward everywhere around the circumference — a hoop stress, which the intact structure of the ring simply resists. With respect to the plane of the ring the interior flux distribution is mirror-symmetric, so the axial components cancel exactly. Every force is therefore either blocked by the structure or annulled by its opposite, and there is no propulsion. Warfield flags the escape route in advance: "if the Lorentz forces were somehow asymmetrical with respect to both sides of the plane of the ring, there would be propulsion. Commit this last concept to memory."
Diagram 5 supplies the missing asymmetry the ordinary way, with a second coaxial ring carrying current in the same sense — a two-turn solenoid. Each ring now sees a flux density greater on the side facing the other ring, and each is driven toward the other. Warfield again rejects this as impractical: on contact the pair becomes a single ring and motion stops.
Diagram 6: the pulse
Diagram 6 is the proposal. A magnetic flux compression generator, attached to the ring, emits a uniform magnetic pulse from the ring's centre directed to one side of the ring's plane, toward +y. For a very brief interval the pulse distorts the field on that side and destroys the mirror symmetry of Diagram 4. The radial outward forces survive and are still blocked by the structure, but there are now net axial forces around the whole circumference directed toward +y with nothing to cancel them. During each pulse the ring is propelled along its axis. Warfield's summary of the mechanism is that "the directed magnetic pulse mimics the magnetic field that was induced by the upper ring as illustrated in diagram 5, even though that ring is nonexistent." A rapid train of pulses gives continual motion. Expanding the field on one side drives the ring one way; contracting it drives the ring the other.
He then makes the paper's decisive claim. The reaction force on the generator is opposite to the emitted pulse, but the thrust on the ring may be in the same direction or the opposite one, "these two forces do not necessarily have to counteract one other, nor are they unavoidably equal to each other, conceivably the disparity in magnitude is massive."
Appendices
Appendix 1 illustrates hollow-tube and helical magnetic flux compression generators, and concedes that these are explosive, single-shot devices; the scheme requires a non-explosive generator capable of rapid repeated pulses, which Warfield says he believes exists but is "not readily available for review in the literature, given that they are classified." Appendix 2 reproduces the well-known photograph of a frog levitated diamagnetically inside a solenoid, and argues from it that an astronaut in such a craft would not experience "compaction," so that very high accelerations could be sustained without harm. Appendix 3 compares the predicted craft — disc-shaped, strongly magnetic, emitting powerful magnetic pulses and electromagnetic radiation from its underside, propelled along its axis, needing no propellant — with photographs of reported unidentified flying objects, and closes with the suggestion that if such craft exist, their builders "do not manipulate gravity as assumed, but rather they are the absolute masters of electromagnetism."
Assessment
The paper's real merit is its discipline about the negative cases. Warfield does not claim that a lone current loop propels itself; he works through Diagrams 1 and 4 and concludes, correctly, that the internal Lorentz forces sum to zero net thrust and leave only a hoop stress. He is equally clear that the two-ring and two-wire cases, while genuinely producing motion, are useless because the motion terminates. Many propulsion proposals of this kind never get as far as identifying which configurations do not work. The interior-field bookkeeping in Diagrams 2 and 3 also reproduces the standard attraction and repulsion of parallel currents, which is a fair check that the geometrical reasoning is being done carefully.
The difficulties are structural, and the first is decisive. That a closed current distribution exerts no net force on itself is not an accident of symmetry that a clever geometry might defeat; it is a theorem of Maxwell's equations, following from the vanishing of the volume integral of the total Maxwell stress over a surface enclosing the whole system when no field momentum crosses it. Warfield's Diagram 6 does not evade this, because the pulse generator is stipulated to be attached to the ring. Generator plus ring plus radiated field is a closed system, and the momentum it gains must be balanced by the momentum the pulse carries away. Warfield sees this objection coming and answers it not with a calculation but with a denial: the two forces "do not necessarily have to counteract one other." Nothing in the paper derives that. It is the one step that has to be earned and the one step that is asserted.
The second difficulty is that the paper contains no numbers whatever. There is no estimate of the ring current, the interior flux density, the pulse amplitude, the pulse duration, the duty cycle, or the resulting thrust — not even an order of magnitude. Since the field momentum carried by a directed electromagnetic pulse of energy U is U/c, a scheme that produced thrust only by field-momentum recoil would be a photon rocket, with about 3.3 micronewtons per kilowatt; any claim to do better needs to say by how much, and against what. A propulsion proposal that never computes a force cannot be compared with any measurement, and so cannot be tested.
The third is the frog. Diamagnetic levitation of a frog in a roughly 16-tesla solenoid is a real and well-documented result, but the paper misreads it twice. A levitating frog is in equilibrium and is not "accelerating away from the surface of the Earth"; it is at rest. And its lack of internal stress follows from the fact that the diamagnetic force is a body force distributed through the tissue nearly in proportion to local mass density, which is precisely why it mimics free fall. Warfield's device does not act that way: its Lorentz forces are confined to the conductor of the ring, as he himself insists throughout, so an occupant would be accelerated by contact with the structure and would feel the full inertial load. Weightlessness and absence of inertia are also not the same thing, and the appendix treats them as interchangeable.
Finally, the paper's closing turn to unidentified flying objects is not argument. The inference runs from a device whose feasibility has not been established to photographs on a hobbyist website, and it invites the reader to take the resemblance as mutual support. Stripped of that, what remains is a clearly drawn geometrical exercise showing that current loops are internally balanced, together with an unsupported claim that a pulse fired from a source bolted to the loop can unbalance the whole.