Electromagnetic Propulsion via a Vacuum-Interactance Push

Scientific Paper
Title	Electromagnetic Propulsion via a Vacuum-Interactance Push
Read in full	Link to paper
Author(s)	Blair M Cleveland
Keywords	crossed-field antenna, electromagnetic momentum density, Graham and Lahoz experiment, Lorentz force, Poynting vector flux, electromagnetic propulsion, vacuum interactance
Published	1998
Journal	Electric Spacecraft Journal
Number	24
Pages	6-16

Read the full paper here

Abstract

Cleveland's paper won first place in the Electric Spacecraft Journal competition for innovative concepts in electric propulsion. [Electric Spacecraft Journal Issue No. 24 , 1998]

The “Lorentz force” equation is missing a force term proportional to the rate of change of electromagnetic momentum density carried by the Poynting vector-flux E x B. An abruptly pulsed crossed-field device (non-radiating) is proposed to interact with the “vacuum-medium” thereby creating an action-reaction propulsive force (push) which can be utilized for transportation means.

Overview

The paper — subtitled "An electromagnetic inertial impulse drive system", and printed in Electric Spacecraft Issue 24, Oct/Nov/Dec 1996, pp. 6–16 — proposes a propulsion method that ejects no mass. Blair M. Cleveland's thesis is that the electromagnetic field itself possesses mass and can store momentum, that momentum can be exchanged with the vacuum, and that a device generating an intense, non-radiating, one-sided Poynting vector flux would therefore be pushed by space in the manner of a body pushing off a wall. He calls the mechanism a vacuum interactance, and is careful to note that the term is his own, not that of E. G. Cullwick, whose Electromagnetism and Relativity supplies the underlying force expression.

The technical core is a claim about a missing term. The Lorentz Force as printed in textbooks, F = dp/dt = qE + q(v × B), accounts for forces on charges but not for the momentum residing in the field between them; Cleveland argues that restoring Newton's Third Law for the combined system of charges and field requires an additional term −(d/dt)(E × B)·dV. In a region containing no charges this term is all that is left, so the equation becomes a statement purely about the interaction of field momentum with the vacuum. The article is explicitly presented as "an introductory treatment only… a work in progress", requiring "further study and testing for proof of principles"; it offers a conjecture plus a proposed test setup, not a measured thrust.

The argument

From Faraday's orthogonality to the Poynting vector

Cleveland starts from a passage in Faraday's Diary (1832) stating that electricity, magnetism and motion "may be represented by three lines at right angles to each other". Drawing that as a rectangular vector diagram and applying the right-hand rule gives three cross products: −v × B = E (electricity), v × E = B (magnetism) and E × B = v (motion), with the equilibrium condition v = E/B — the "unity of forces". The third of these, he stresses, says a motional force can be generated wherever an electric field is made to coexist perpendicular to a magnetic field: a crossed field. Equation 8 is the familiar velocity-filter condition (a charge that is too slow is deflected by the Coulomb force qE, one that is too fast by q(v × B), one at just the right speed passes through), and Cleveland notes that boosting the fields while the particle is inside the crossed-field zone turns the filter into "a momentum booster".

Equation 7 mirrors Poynting's theorem, S = E × B (power per area), from which the electromagnetic momentum density follows as G = S/c² (momentum per volume). He emphasises, citing Pugh and Pugh, that S is not zero for static field configurations even though div S = 0 everywhere, so that the Poynting vector can be used to map sources (dynamos) and sinks (motors, resistors) of energy flow in DC circuits.

Electromagnetic fields have mass

This is the pivot of the argument, and Cleveland sets it in display type. Total mass is written M = mm + em — mechanical plus electromagnetic — with the electromagnetic part em = U/c², U = ½E² + ½B² being the field energy density. A charged capacitor therefore weighs more than an uncharged one; Cleveland cites James Woodward's careful capacitor-bank weight measurements, done with a resonant detector, as recording mass changes of several milligrams.

Two supporting authorities are quoted at length. H. G. Booker's "electronic wheel" — a fixed conducting circle whose rim consists only of the electrons constituting the current — has an inertia "controlled by the electric charge of the electrons rather than by their mass". And Richard Feynman's disc paradox is quoted from the Lectures, including the resolution: field Angular Momentum "must have been put there when the field was built up. When the field is turned off, the angular momentum is given back… This mystic circulating flow of energy, which at first seemed so ridiculous, is absolutely necessary." Cleveland extends the picture to the Earth, whose axial magnetic field and radial electrostatic field give a Poynting vector pointing west to east — suggesting to him that part of the Earth's spin is stored as field momentum.

Cullwick's missing term

From Cullwick he takes the statement that "the inertia of a system is not confined to the material bodies", together with the reaction force density

F′ = −(d/dt)(E × B)·dV

whose counterpart (d/dt)(E × B)·dV Cleveland labels the vacuum-interactance term. Adding it to the textbook expression gives his Eq. 15,

F = qE + q(v × B) − (d/dt)(E × B)·dV

and in charge-free vacuum simply F = −(d/dt)(E × B)·dV. That, he says, is an action–reaction system: the field pushes on space and space pushes back, "a vacuum Lorentz force".

The Graham and Lahoz experiment

The empirical anchor is the 1980 Toronto work of G. M. Graham and D. G. Lahoz, published in Nature 285 (1980) 154–155 as "Observation of static electromagnetic angular momentum in vacuo". A cylindrical vacuum capacitor at V₀ = 1–2 kV sits in an axial field B_c = 0.5–1 T; the B field is modulated at 0.3 Hz and the E field at 220 Hz, and a torsional pendulum read by an optical lever and laser detects a torque of order 10⁻¹² N·m, with an electronic feedback system. Graham and Lahoz's own summary is quoted: the observed changes in angular momentum "agree with the classical theory within ~20 %", implying "that the vacuum is the seat of something in motion whenever static fields are set up with a nonvanishing Poynting vector, as Maxwell and Poynting foresaw."

Cleveland's reading is that the crucial run was the third, in which the dielectric and magnetic materials were removed from the detector volume and the reaction force was still detected — in his words, "Graham and Lahoz seem to have detected an interaction between the E × B field and the vacuum." He also quotes their own more guarded conclusion, that "no known particle can be identified as the agent of the observed electromagnetic angular momentum exchange. However, this does not imply that a new entity has to be introduced, because the concept of energy momentum carried by the macroscopically quasistatic electromagnetic field is already contained in Maxwell's equations."

The proposed device

Since radiation would carry momentum away, Cleveland insists — again in display type — that "the fields generated by this electromagnetic propulsion technique must not propagate away from their source. They must interact with the vacuum in the immediate vicinity of the source, like pushing off from a wall." Radiation "is like the ejection of mass"; what is wanted is a local inertial impulse.

The listed components are a power source, a crossed-field device for creating an intense thrust vector, a high-energy pulse modulator with fast rise time, an impedance-matching network, and a mechanical structure to couple the impulse to the hull (or an array of such devices forming the hull). The first candidate is the crossed-field antenna of Kabbary, Hately and Stewart, which synthesises S = E × B directly from separately driven electric and magnetic structures and whose physical size is independent of the radiated wavelength. But Cleveland immediately rejects it: the design of Fig. 3 "will not satisfy the requirement and will have to be redesigned", because what is needed is a curl-free Poynting vector asymmetry — flux that does not curl back onto the source, since that would cancel the thrust, with the resultant vector passing through the centre of mass.

His preferred candidate is therefore a cavity-mode thruster (Fig. 4): a cavity resonator does not radiate but resonates field patterns inside its volume, and can be thought of as a container holding electromagnetic mass whose volume density is electrically controllable — "a way to control the mass and inertia of an object". The block diagram (Fig. 5) is a conventional pulsed-power chain: DC primary source, charging inductance, trigatron, pulse-forming network impedance-matched to the load, pulse transformer and air-core coupling into the thruster, with gigawatt peak power on nanosecond timescales. The proposed test (Fig. 6) hangs the thruster on a waveguide balance-arm with self-contained high-power electronics as the counterweight.

Two patents are offered as precedent: T. T. Brown's "Electrokinetic apparatus" (US 3,187,206, 1965), tested in vacuum, of which Cleveland quotes "The propelling force, however, is not reduced to zero when all environment bodies are removed beyond the apparent effective range of the electrical field"; and R. L. Schlicher's "Nonlinear electromagnetic propulsion system and method" (US 5,142,861, 1992), an antenna pulsed at extremely low frequency to trap magnetic flux inside the loop geometry. Both, he notes, call for high-permittivity and high-permeability materials and for arrays of thrust elements.

The conclusion returns to Maxwell — "all energy is the same as mechanical energy" — and to the proposal that if mass can be varied electrically and inertia measures mass, then a sudden mass change produces an inertial reaction that, properly directed, changes momentum. The closing image is a jellyfish, which moves by taking water into a cavity and expelling it: "Think of the jellyfish as a spacecraft, the water as the vacuum medium, and the ocean of water as the universe."

Assessment

The paper's real strength is that it builds on genuine, mainstream physics rather than inventing new laws. Electromagnetic field momentum density G = S/c² is standard; hidden momentum in static fields is a well-documented subject, and Cleveland's reference list (items 10–26) is a serious bibliography of it — Romer, Pugh and Pugh, Shockley and James, Furry, Stedman, Aguirregabiria, Gough, Herrmann and Schmid, Hnizdo — that any reader wanting to learn the topic could work through profitably. The Feynman disc paradox and the Graham–Lahoz measurement are correctly described, and the insistence that a working device must be non-radiating and must produce a curl-free Poynting flux shows that the author understood exactly where the difficulty lies. He is also candid: he rejects his own first candidate device in the body of the paper, states that the treatment is introductory, and reports no measured thrust.

The central difficulty is nevertheless fatal to the argument as presented, and it is a matter of what the equations actually say. Cullwick's term is not a "missing" force in the sense of an omission from electrodynamics; it is the rate of change of the field's own momentum, and Maxwell's stress tensor already accounts for it. Writing dp_mech/dt + dp_field/dt = surface integral of the Maxwell stress makes plain that momentum conservation holds for charges plus field, with no third party required. The vacuum is not a fourth entity that can absorb recoil; Graham and Lahoz themselves say so in the sentence Cleveland quotes — the effect is "already contained in Maxwell's equations" and does not require a new entity. Their result confirms that field momentum is real and localisable, which is exactly what makes the self-propulsion inference fail: if the field carries the momentum, then a closed non-radiating system cannot gain net momentum, because whatever momentum the fields hold must be given back when the fields are switched off — which is Feynman's own resolution of the disc paradox, quoted approvingly two pages earlier. A cavity resonator that does not radiate cannot, for that very reason, export momentum.

Several supporting steps are asserted rather than derived. The set of relations −v × B = E, v × E = B, E × B = v is dimensionally inconsistent as written and can only be read as a mnemonic for orthogonality, not as equations; Cleveland does warn that "some constants of proportionality have been omitted", but the argument then leans on Eq. 7 as though it licensed motion from crossed fields. The step from "the field has mass" to "the mass of an object can be varied electrically, hence its inertia controlled" skips the question of what the reaction partner is. The Earth-spin remark is offered as a suggestion and is not quantified. And the identification of vacuum energy with the astronomical missing mass, taken from a New Scientist piece, conflicts with the measured value: the vacuum energy density predicted by quantum field theory exceeds the observed Cosmological Constant by many tens of orders of magnitude, and Dark Matter is in any case inferred from clustering and lensing, not from a uniform vacuum energy.

The experimental precedents are weaker than presented. T. T. Brown's electrokinetic thrust is now well understood as ionic wind at atmospheric pressure, and the residual force in vacuum has not been independently replicated at any significant level; the Schlicher device likewise has no confirmed replication. Against this background it is worth recording that Cleveland's own co-author on later work, George Hathaway, published a rigorous null result on a different claimed gravity-modification effect (Gravity modification experiment using a rotating superconducting disk and radio frequency fields, 2003), which shows the standard of measurement such proposals must eventually meet.

Most telling is the editor's note appended by Electric Spacecraft Journal to this very article: "Cleveland has recently informed ESJ that he doesn't believe the cavity resonator will be able to generate the fields needed to synthesize a Poynting vector." The author had already withdrawn confidence in his own preferred device before the issue went to press. That is to his credit as a matter of intellectual honesty, and it is the fairest summary of the paper's standing: a well-read, well-referenced conjecture, honestly labelled as such, whose proposed embodiment its own author no longer endorsed and whose central inference is blocked by the momentum bookkeeping of the theory it invokes.

See also

• Lorentz Force · Maxwell's Equations · Electrodynamics · Electromagnetism
• Newton's Third Law · Angular Momentum · Inertia · Mass
• Vacuum · Casimir Effect · Category:Zero Point Energy
• Michael Faraday · Richard Feynman
• Gravity modification experiment using a rotating superconducting disk and radio frequency fields
• Category:Propulsion · Category:Antigravity