Dynamics and morphology of dendritic flux avalanches in superconducting films

TL;DR

This paper introduces a fast numerical method to analyze the nonlinear, nonlocal electrodynamics of superconducting films, revealing stability conditions and flux avalanche behaviors consistent with experimental observations.

Contribution

A novel numerical procedure for analyzing nonlinear, nonlocal electrodynamics in superconducting films, enabling detailed study of flux avalanche stability and morphology.

Findings

Flux patterns match experimental magneto-optical images.

Identified a threshold magnetic field for avalanches.

Predicted temperature rise during avalanches.

Abstract

We develop a fast numerical procedure for analysis of nonlinear and nonlocal electrodynamics of type-II superconducting films in transverse magnetic fields taking into account realistic boundary conditions. Using this procedure we explore stability of such films with respect to dendritic flux avalanches. The calculated flux patterns are very similar to experimental magneto-optical images of MgB2 and other superconductors, where the avalanche size and morphology change dramatically with temperature. We also find a threshold magnetic field, which agrees with both experiments and linear stability analysis. The simulations predict the temperature rise during an avalanche, where for a sub-microsecond time T ~ 1.5 Tc, and a precursor stage with large thermal fluctuations.