Scattering of quasi-one-dimensional solitons on impurities in large Josephson junctions

TL;DR

This paper investigates how fluxons, or magnetic flux quanta, scatter when encountering impurities in a quasi-one-dimensional Josephson junction, combining analytical and numerical methods to understand transmission and retrapping phenomena.

Contribution

It provides new analytical formulas and numerical analysis for fluxon scattering on various impurity shapes in Josephson junctions of intermediate width.

Findings

Analytical formulas match numerical results for junction widths of several $bb \\lambda_J$.

Retrapping current depends on impurity shape and junction width.

Good agreement between theory and simulation for intermediate junction widths.

Abstract

Fluxon transmission through impurities of different shape in a quasi-one-dimensional long Josephson junction is investigated. The junction width is significantly less than its length but, at the same time, is of the order of the Josephson penetration length $\lambda_J$ or exceeds it. The retrapping current on the impurities of the point, line and rectangular shape is computed as a function of the junction width both numerically and analytically. Good agreement between the analytic formulae and the numerical simulation results for the intermediate (several $\lambda_J$) junction width is observed.