Simple superconductor question

[sniffer]

suppose we have a superconductor speciment above Tc, and we put it in magnetic field. then we cool it down to below Tc, then a screening current is produced.

where does the electron get the energy to initiate the current on the first time?

 

[Caesar_Rahil]

Magnetic field. If not, then the energy it gets is from the energy you used to cool it down.

 

[sir-pinski]

The energy for initiating the screening current in a superconductor comes from the external magnetic field. When the superconductor is above its critical temperature (Tc), it does not have perfect conductivity and can allow some magnetic flux to pass through it. However, as the temperature drops below Tc, the superconductor's conductivity increases significantly and it starts to expel the magnetic field, generating a screening current to cancel out the external field. This process is possible due to the formation of Cooper pairs, which are pairs of electrons that can move through the lattice without resistance. Therefore, the energy for initiating the screening current comes from the external field, but it is sustained by the superconductor's unique properties and the Cooper pairs.