Study of the skin effect in superconducting materials

Abstract

The skin effect is analyzed to provide the numerous measurements of the penetration depth of the electromagnetic field in superconducting materials with a theoretical basis. Both the normal and anomalous skin effects are accounted for within a single framework. The emphasis is laid on the conditions required for the penetration depth to be equal to London's length, which enables us to validate an assumption widely used in the interpretation of all current experimental results.Comment: 4 pages, 2 figures. arXiv admin note: text overlap with arXiv:1507.0333

An Observable Prerequisite for the Existence of Persistent Currents

“…Because the inertial force m e dj n dt has been shown to be negligible [15,16], the electric force c n eE and the friction one − m eτ n j n cancel each other, so that Eq. (3) boils down to Ohm's law, as expressed in Eq.(1).…”

“…(1) is valid for dj n dt = 0 and dj n dt = 0 as well, Eq. (4) holds in a superconducting material only if dj s dt = 0, because dj s dt = 0 defines conversely the persistent current case, for which the friction force is no longer active [15,16].…”

“…Additional evidence is provided by commercial microwave cavity resonators, made up of superconducting materials, displaying a very high, albeit finite conductivity (see [3] lowest line in p.38). Besides, the observable consequences of finite σ, regarding the skin [12,13] and Meissner [6,14] effects, have been discussed recently [15,16].…”

Study of the Superconducting to Normal Transition

“…However, the whole analysis 1-3 relies on the two-fluid model [6][7][8][9][10] , for which the conduction electrons comprise a homogeneous mixture of superconducting and independent electrons. Thus, since the BCS model is known to be characterised 4,5 by a many-body variational state at thermal equilibrium with Bogolyubov-Valatin excitations which are complex entities, quite unrelated to independent electrons, Refs.…”

Meissner Effect in Classical Physics

“…It is usually believed that its cause is hidden in quantum mechanical dynamics, and this fact is generally found in student textbooks. Although there have been some proposals for its explanation, both within classical physics [1][2][3] and quantum mechanics [4], so far, no one has been able to find its true dynamics without introducing some assumptions or new phenomena, making it difficult to obtain a conceptual understanding.…”