Dynamics of the Meissner effect: how superconductors expel magnetic fields

Dynamics of the Meissner effect: how superconductors expel magnetic fields

A normal metal cooled into the superconducting state expels the magnetic field from its interior. How does this happen? I have understood it several years ago and have attempted to explain it to solid state physicists [1], however solid state physicists believe that it is already explained by BCS theory [2] and are not receptive to alternative explanations. The fact however is, BCS theory only describes the final state but not the process. The Meissner effect results from outward flow of a perfectly conducting fluid that carries the magnetic field lines with it. This should be intuitively obvious to plasma physicists, what is not so obvious is (a) what is the nature of this fluid, that cannot carry either charge or mass, since if it did it would lead to a charge and/or mass imbalance, (b) what drives the outward flow, and (c) how is angular momentum conserved, since there is angular momentum in the Meissner current in the final state and there was none in the initial state. I will provide answers to these questions using standard concepts of plasma physics that are not commonly used in solid state physics, combined with standard concepts of solid state physics that are not commonly used in plasma physics.

[1] J. E. Hirsch, Phys. Rev. B 95, 014503 (2017).

[2] J. Bardeen, L. N. Cooper, and J. R. Schrieffer, Phys. Rev. 108, 1175 (1957).