Stimulated transparency of a superconducting plate caused by nonlinear interaction of electromagnetic waves

Abstract

A nonlinear effect in the electrodynamics of hard superconductors is predicted and theoretically studied. It is shown, that a low-frequency (LF) electromagnetic wave can pass through a superconducting plate, due to its interaction with another wave propagating in the opposite direction, even at small amplitudes of the LF wave when it cannot reach the opposite boundary of the sample without assistance. The dependence of the LF surface impedance on the amplitude of the high-frequency (hf) wave is studied within the framework of the critical state model. The LF surface impedance is found to be drastically increased by the overlapping of the regions of wave penetration.

Flux-line cutting in granular high-Tcand semi-reversible classical type-II superconductors

“…The numbers along the profiles then increase from zero as H y is applied, traverses a full sweep extending between + and −H y,max and terminates at The mesa-like structure established during the field cooling (curve 0) is permeated with z-directed flux lines. As H y is applied the increase in the internal surface field, (14) causes additional flux to penetrate along the surfaces of the slab and impinge upon the sides of the mesa, thereby forming two V-shaped minima. Inspection of curves 1 and 2 of figure 9(a) shows that, as the minima advance to the centre of the specimen, the flux density threading the facades of the mesa is seen to drop.…”

“…The majority of these measurements have been carried out on samples subjected to a magnetic field changing only in magnitude. The high-T c superconductors behave as hard superconductors and, therefore, their magnetic response under such conditions has been well described with models [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] based on the well known Bean critical state concept [16].…”