Cherenkov radiation from fluxon in a stack of coupled long Josephson junctions

TL;DR

This paper investigates Cherenkov radiation emitted by fluxons in coupled long Josephson junctions, revealing conditions for radiation emission, resonances, and potential detection methods.

Contribution

It provides a systematic analysis of Cherenkov radiation in coupled Josephson junctions, including new formulas for resonance positions and insights into detection possibilities.

Findings

Fluxon motion can produce Cherenkov radiation under certain parameters.

Resonances emerge due to wave-fluxon interactions in moderate-length junctions.

Formulas accurately predict resonance positions considering nonlinear effects.

Abstract

We present a systematic study of the Cherenkov radiation of Josephson plasma waves by fast moving fluxon in a stack of coupled long Josephson junctions for different fluxon modes. It is found that at some values of parameters current-voltage characteristic may exhibit a region of the back-bending on the fluxon step. In the opposite limit the emission of the Cherenkov radiation takes place. In the annular junctions of moderate length the interaction of the emitted waves with fluxon results in the novel resonances which emerge on the top of the fluxon step. We present more exact formulas which describe the position of such resonances taking into account difference between junction and non-linear corrections. The possibility of direct detection of the Cherenkov radiation in junctions of linear geometry is discussed.