A superconducting wire($SC$) is moved rapidly in a magnetic field( $1$ $Tesla$), what would happen to the wire? Are there any forces induced of attraction or repulsion?

In a typical conductor, we know that if it is moved around a magnetic field $-V$ is induced within the wire based on Faraday's law, however, with the condition of the $SC$ what could happen if $R = 0$ $ohms$?

Will Faraday's law still be applied to that wire with no resistance? moving a $SC$ in a magnetic field will not induced $EMF$?

  • $\begingroup$ I think a plot of the experiment you have in head is warm welcome. The superconducting electromagnetism is well understood using the London theory. You could resolve the problem yourself. The problem in your case is that you want the superconductor to move. In some circumstance, non-trivial effects appear, related to the so-called London momentum. As long as the wire does not form a loop, I don't see any reason why the Faraday's law should be invoked, though (there is trivially no magnetic flux then). Only the Ampère's law should be useful. So again, a plot please :-) $\endgroup$
    – FraSchelle
    Mar 12, 2014 at 11:01
  • $\begingroup$ I assume by "plot" you mean a better explanation of the set up? If we had a SC that's length is 5 m, and moved it up and down in a magnetic field of 1 Tesla would faraday's law still hold? Faradays law states that V will be induced due to the change in flux over time, however ,this is a SC where R = 0, shouldn't V = 0 as well based on ohms law? $\endgroup$
    – Pupil
    Mar 12, 2014 at 11:57
  • $\begingroup$ No by plot, I mean a plot, a drawing, a scheme, whatever like a picture, an image, something like that, anything which help understanding how the field is oriented with respect to the superconductor, what the superconductor is doing, etc... $\endgroup$
    – FraSchelle
    Mar 13, 2014 at 9:07
  • $\begingroup$ @FraSchelle well the question is quite general, and simple in a sense I doubt a plot is necessary. If you still require a plot I will produce one immediately. However, my initial question is relating Faraday's law of induction to ohms law with any conductor. Even in the case of superconductors, if R = 0 how can you induce any EMF in a superconductor by changing it's surrounding magnetic field? $\endgroup$
    – Pupil
    Mar 13, 2014 at 11:37
  • $\begingroup$ Hi, what about this plot? hyperphysics.phy-astr.gsu.edu/hbase/magnetic/imgmag/genwir.gif hyperphysics.phy-astr.gsu.edu/hbase/magnetic/genwir2.html I'm still curious about answer to this question $\endgroup$ Jul 1, 2014 at 19:12

3 Answers 3


The induced current will flow in such a way that the flux produced will tend to cancel the change in flux. According to traditional classical electrodynamics, the magnetic field does not do any work and it is the electric field and the charge carriers which do the work and ultimately limit Faraday's law in extreme cases.


I suppose that the moving wire is a closed circuit and that the magnetic flux enclosed is time-dependent. The Faraday’s law is of course always applicable. The current will not be infinite. Yes R=0 but, what about the self inductance L? It is never zero, in such a manner that the total E field will be null. If you make the calculations the electric field in the superconducting wire has two contributions. The first one related to the variation of the external magnetic flux and the second associated to the time-dependent current by means of the self inductance L.


Kind of complicated thing to answer, best way is to do an experiment and not rely on math completely! and the fact that this is still unknown territory.

I will try my best, watch this ted talk very helpful:


Superconductivity is a phenomena of absolutely 0 electrical resistance. Given that a material is superconductive, the magnetic field lines go through the material to leave it in a state of "quantum locking". Given that Faraday's law predicts how a magnetic field interacts with a circuit to produce emf this law i assume will not apply due to the fact that the magnetic field is not interacting with the superconducting wire but the magnetic field is directly penetrating through the sc wire. But at the same time leaving it in a state of quantum locking i assume is still interaction?. So 2 answers, may be and may be not.

This is an assumption, i would try to do an experiment before coming to any conclusions.


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