Study of Vortex Avalanches using the Bassler-Paczuski Model

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.