Study of Vortex Avalanches using the Bassler-Paczuski Model

TL;DR

This study models vortex avalanche flux noise in Type-II superconductors using the Bassler-Paczuski model, revealing power-law frequency dependence and finite-size effects consistent with experimental observations.

Contribution

It applies a kinetic model to simulate vortex flux noise, providing insights into its spectral behavior and finite-size effects, which were not previously characterized in detail.

Findings

Flux noise follows a power-law with frequency, S_Φ(ω) ∼ ω^(-1.4).

Finite lattice size causes a high-frequency knee in the noise spectrum.

Deviations from experiments are due to uncertainties in material parameters.

Abstract

We have carried out a model calculation of the flux noise produced by vortex avalanches in a Type-II superconductor, using a simple kinetic model proposed by Bassler and Paczuski. Over a broad range of frequencies, we find that the flux noise $S_{\Phi}(\omega)$ has a power-law dependence on frequency, $S_{\Phi}(\omega) \sim \omega^{-s}$, with $s \sim 1.4$ in reasonable agreement with experiment. In addition, for small lattices, the calculated $S_{\Phi}(\omega)$ has a high-frequency knee, which is seen in some experiments, and which is due to the finite lattice size. Deviations between calculation and experiment are attributed mostly to uncertainties in the measured critical current densities and pinning strengths of the experimental samples.