2
$\begingroup$

If a superconductor was placed inside a magnetic field(below critical magnetic field) can it experience the Lorentz force = $IL\times$ $B$?

Also, if a superconductor moving inside a magnetic field, will it have an induced-EMF $\epsilon$ = -$vBL$? Not sure how these superconducting electric motor/generators would work if not.

$\endgroup$
  • $\begingroup$ I suppose not and my feeling is based on the imagination that the electron's intrinsic spins and by this the magnetic dipole moments are aligned or neutralized in pairs in superconductors. There has not to be Lorentz force nor magnetic or electric induction. $\endgroup$ – HolgerFiedler Apr 20 '15 at 19:50
  • $\begingroup$ I would say you need inhomogeneity in the magnetic field and not too symmetric superconductor to let the superconductor rotating in a magnetic field. B penetrates only through vortices, and the electrons inside the vortices follows the Lorentz force. Otherwise current flows at the edges and screen the magnetic field. $\endgroup$ – FraSchelle Apr 21 '15 at 10:15
  • $\begingroup$ When a superconductor moves, it can produce a voltage drop, a current or a magnetic field. This last effect is called the London momentum effect. It's not well documented, but you can find some references using the keywords London momentum effect or rotating superconductor. To understand your question, a scheme of the experiment you have in head is necessary, as well as the type of superconductor (type 1 or 2). Check on Wikipedia first, and then ask a more precise question please. Your two equations are meaningless without (at least) a drawing. $\endgroup$ – FraSchelle Apr 21 '15 at 10:15
  • $\begingroup$ Superconductors are not so interesting in the circuit limit (lumped element limit), except perhaps Josephson systems in the microwave regime. So one needs to come back to electromagnetism in the version established by London's brothers or using e.g. Ginzburg-Landau formalism. $\endgroup$ – FraSchelle Apr 21 '15 at 10:17
  • $\begingroup$ Current flow in superconductors is on the surface wouldn't that generate a Lorentz force? Since superconductors expel the magnetic field passing through the material, however the surface is exposed to the magnetic field lines and should interact? $\endgroup$ – Pupil Dec 30 '15 at 21:46

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.