Comment on "Reversible superconducting-normal phase transition in a magnetic field and the existence of topologically protected loop currents that appear and disappear without Joule heating" by Hiroyasu Koizumi

TL;DR

This paper critiques an alternative superconductivity theory, arguing that it incorrectly predicts no Joule heating and misinterprets energy conversion during the superconducting-normal transition.

Contribution

It provides a critical analysis of Koizumi's theory, clarifying the energy dynamics and thermodynamics involved in superconducting transitions.

Findings

The kinetic energy is much less than magnetic field energy.

Both kinetic and magnetic energies decrease during transition.

The critique emphasizes the difference between reversible and irreversible processes.

Abstract

This comment is written on the article by Hiroyasu Koizumi, in which an alternative theory of superconductivity is proposed. No Joule heating is predicted in this theory unlike the conventional BCS-London theory of superconductivity. The theory is based on the author's opinion that the kinetic energy for the supercurrent is converted into the energy of the magnetic field during the transition of a bulk superconductor into the normal state in the presence of a magnetic field. The Comment indicates that this opinion cannot be correct, since the kinetic energy is much less than the energy of the magnetic field and both of these energies decrease during the transition to the normal state, according to the generally accepted point of view. It is briefly explained how a reversible thermodynamic process differs from an irreversible process.