While browsing for Space propulsion, I've found the following article

As shown in Figure 2, the conductor I0 gets through the coil L0, and they are fixed together and form a system. a is the main view and b is the left view. When there are time varying currents flowing through the conductor I0 and the coil L0 respectively, the moving electrically charged particles in the conductor I0 are located in the magnetic field generated by the coil L0 and their direc-tions are unparallel. The conductor I0 will be subjected to two Lorentz forces. One is the acting force that the cur- Figure 2. The operating principle of Lorentz Force Propel-ler rent-carrying conductor is subjected in the magnetic field generated by the current and the other is the acting force that it is subjected in the magnetic field generated by the induced electric field. For the above-mentioned system, the former acting force is an internal force of the system. Its reacting force is the Lorentz force that the coil wind-ing is subjected in the magnetic field generated by the current-carrying conductor. Since the conductor I0 and the coil L0 are fixed together, the couple of acting force and reacting force can’t make any relative movement between the conductor I0 and the coil L0. So the relative position between them is also unchanged. The latter act-ing force is an external force of the system and it hasn’t any reacting force.

When the current-carrying conductor I0 moves under the action of the force, the coil L0 will be driven and move together with the conductor. Therefore, the system achieves propulsion.

Do you think it is true. Thank you.


2 Answers 2


The linked paper looks very bogus.

Electromagnetic propulsion by itself is nothing unusual. Pushing against the Earth's magnetic field or similar can very well be used to generate some mild thrust.

One would expect such a paper to include some kind of operating principle (other than insisting that Newton’s third law is not tenable).

... Or some references to existing work in the field? Seems to be just a stack of introductory physics textbooks.

... Or some equation or calculation describing the system? Maxwell's equations are quoted, but that's it.

Being familiar with some of the physics supposedly used here, this is just mumbo jumbo strung together without any substance.

Just another trash journal to add to the list.

  • 2
    $\begingroup$ I think the paper is not trustworthy at all. $\endgroup$
    – Uwe
    Jan 26, 2023 at 17:30

The same theory they use to predict the effect has been mathematically proven to conserve energy and momentum. In short, no correct application of electromagnetic theory can result in prediction of a left over force. Any such left over force is an indication that something was left out or misapplied.

If someone does invent such a thruster, they will need to prove it functions by physical measurements, not handwaving about forces without reacting forces. They need to demonstrate that current theory fails. Electromagnetic theory will then have to be modified to be able to describe the newly discovered behavior.

  • $\begingroup$ ...and such a discovery would be guaranteed to earn a nobel prize. If this was possible, then some smart researcher would have done it already and we'd know about it. $\endgroup$ Jan 27, 2023 at 12:31
  • $\begingroup$ You can temporarily transfer some momentum to the EM field, so if you look only at the forces on the charges which create the field, it may look like momentum is not conserved. You can even transfer some momentum permanently to the field if you generate EM waves, so in principle, you can produce thrust this way. But under any reasonable power consumption, such thrust would be tiny: to produce 1 N of thrust, you will need at least 300 MW (i.e., 1 N times $c$) of power. $\endgroup$
    – Litho
    Jan 27, 2023 at 16:55
  • 1
    $\begingroup$ @Litho you can't exclude the momentum carried by the electromagnetic waves from consideration any more than you can exclude the momentum of the exhaust from an analysis of a chemical rocket. And there's a much, much simpler way to generate electromagnetic radiation for a photon thruster: get something hot. $\endgroup$ Jan 27, 2023 at 18:29

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.