If one has a superconductor that's being levitated on a track and you apply a force through its c.m. completely parallel to the track it's on (perpendicular to gravity), would there be any kind of friction or loss of momentum from the the magnetic field? Or would it be unimpeded? Not considering collisions with surrounding gas etc..
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In general the answer is yes. Since we are disturbing the electromagnetic field, an electromagnetic wave will be created which leads to a radiative loss. Energy conservation requires that there has to be a net force on the superconductor to make up for that loss.
Now lets assume that the configuration has an additional symmetry, e.g. a rotating superconducting disk over a magnetic field with rotational symmetry. In this case there can be no such em wave. But even then we have to consider that not the entire material is superconductive. Depending on type I or type II superconductors there is a thin layer of material the gets penetrated by the magnetic field and for type II we are even dealing with flux tubes inside the bulk of the material. The material in this volume is not superconductive and we still have eddy currents in these thin layers/tubes. So even in the fully symmetric case there would be losses and a net force would be needed to make up for them.
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$\begingroup$ Thanks for the answer. What math/formulas would you use to find said force. Would you be able to point me towards what that would fall under, or any reading about moving superconductors in a field. $\endgroup$ Commented Oct 9, 2022 at 19:02
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$\begingroup$ @NickArnold I can't give you a quantitative answer. The effect might be quite small for slowly moving superconductors. What I have seen are analyses for AC current losses in superconducting magnets and conductors like in this presentation: indico.cern.ch/event/440690/contributions/1089769/attachments/…. $\endgroup$ Commented Oct 9, 2022 at 20:13