Where does the energy come from? (superconduction)

[nonequilibrium]

When one cools down the temperature of a superconducting material below its critical temperature, a surface current is induced. Where does the energy (needed to create this new kinetic energy of the current) come from?

 

[pallidin]

When one cools down the temperature of a superconducting material below its critical temperature, a surface current is induced. Where does the energy (needed to create this new kinetic energy of the current) come from?

Well, in short, the cooling equipment has a specific role. And THAT takes energy.

 

[nonequilibrium]

Hm, but what if i just threw it into outer space? It'd cool by itself without any equipment.

 

[Antiphon]

The current comes from whatever stray magnetic fluxes are linking the conducting circuit when it goes superconducting.

It's like having a cork at the bottom of a bucket of molasses that abruptly turns to water. What makes the water stir as the cork pops up? Probably the worst analogy I've ever come up with but you get the point.

 

[nonequilibrium]

Hm, I'm not totally getting the analogy :)

But to come back to your first paragraph: ah since there's only an induced current when there was a magnetic field before reaching the critical temperature (after all, the induced current is there to remove that initial magnetic field inside the material), you're saying that when you calculate the energy in the magnetic field inside and outside the material before reaching the critical temperature, this will equal the energy stored in the magnetic field outside + in the current on the surface, after reaching the critical temperature?