In this photo you see on the right-hand side that the outer wall current is negative and the inner wall current is positive. That is, they are directed in different directions. But if the applied magnetic field is in the z direction as shown, then shouldn't they both be in the same direction do to the fact that j_s = -j = rotB? That is the shielding current goes in the opposite direction of the current caused by the magnetic field. Why is it so that the currents are in different directions?
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$\begingroup$ What is the definition of positive current on this diagram? Also, I think it is no helpful to talk about the current caused by magnetic field. You could apply magnetic field at room temperature and then cool down. You would end up with the same distribution. There is applied magnetic field, and magnetic field due to shielding currents, and the latter do whatever is necessary to enforce zero magnetic field in the superconductor $\endgroup$– CryoApr 21, 2021 at 16:33
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$\begingroup$ Nevermind I understand it. I was under the impression that there was still a homogeneous mag field being applied but there isn't. $\endgroup$– mikanimApr 22, 2021 at 9:39
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