Transport ac loss in a long cylinder with a hard superconducting core and normal conducting shell

Abstract

The power loss is analytically derived for a long cylinder with a hard superconducting core and a normal conducting shell under an applied ac current of amplitude I m . The core obeys the critical-state model with a constant critical-current density J c and the shell obeys the Maxwell equations and the Ohm law with a constant permeability µ 0 and conductivity σ . The dependence of the normalized ac loss per cycle per unit length upon I m /I c (I c being the critical current), the normalized frequency, and the radius-filling fraction of the core are studied. We provide a detailed discussion on the nature of the loss in the shell and the description of its low-frequency low-current limit and high-frequency limit.

Alternating current loss in a cylinder with power-law current-voltage characteristic

“…The decrease of q * with increasing f at i m * Ͼ 1.5 may be related to the loss occuring in the normal metal Ag in the shell. 15 The q * at i m * Ͻ 1 to be lower than that calculated from the PL E͑J͒ and the CS q calculated from Eq. ͑1͒ may come from a field dependent J c , which is not considered in the derivation of Eq.…”

Transport ac losses of a second-generation HTS tape with a ferromagnetic substrate and conducting stabilizer

“…The transport ac loss in a long cylinder with a hard superconducting core and a normal conducting shell has been calculated analytically in [30] based on the CS model, the Ohm law, and Maxwell equations. It is concluded that the current in the shell is not an eddy current as commonly named but a transport current that is inductively coupled to the superconducting core.…”

AC susceptibility of a long cylinder with a hard superconducting core and normal conducting shell

“…However, it seems to us that the simplest case of a long cylinder with a hard superconducting core and a normal conducting shell has not been treated systematically. Therefore we have calculated analytically in [12] its transport ac loss as a function of current amplitude at various values of frequency and filling fraction of the superconducting core. Describing the essential feature of the normal current in the shell, we have concluded that it is not an eddy current, as commonly called, but a transport current that is inductively coupled to the supercurrent in the core.…”