Flux Jump Size Distribution in Low-κType-II Superconductors

The size distribution of noncatastrophic flux jumps in cylindrical specimens of Pb + 2 at.%-In alloys in an axial, homogeneous, linearly swept magnetic field has been measured as a function of field at 4.2°K and found to approximate the form $N\left(\varphi \right)=N\left(0\right)\mathrm{}\times \exp (-\frac{\varphi }{\overline{\varphi }})$, where the mean bundle size $\overline{\varphi }$ was of the order of ${10}^2{\varphi }_0$ to ${10}^4{\varphi }_0$. The fraction of the entering flux participating in the jumps was found to have a field dependence similar to that of $\overline{\varphi }$. When surface superconductivity was present, the jumping persisted up to $H_{c3\mathrm{}}$.