SUPERCONDUCTING VORTEX AVALANCHES

We monitor the dynamics of superconducting vortices in the Bean state, as the system is driven to the threshold of instability by the slow ramping of an external field. Individual avalanches, containing as few as 50 vortices, are detected in real time. Thus our experiment is the superconducting analog of monitoring the granular avalanches produced by slowly dropping sand on a sandpile. The observed distribution of vortex avalanche sizes shows a power-law behavior over two decades, proving that the vortex dynamics in the Bean state is characterized by avalanches of many length scales. © 1995 The American Physical Society.