THE CRITICAL STATE AND THE FLUX DYNAMICS IN SQUID ARRAYS

The low transport current in granular high-T(c) superconductors is undoubtedly attributed to the presence of weak links between grains. Magnetization and critical current measurements at very low field indicates that this low transport current behaves as expected from a critical state model. In this paper we show that a simple linear model of the granular system, based on an array of Josephson junctions and holes, can explain the existence of the critical state regime and shows dynamical effects, which have consequences even at low frequency allowing for instance to explain the flux flow resistance of these materials.