Current distribution maps in large YBCO melt-textured blocks

We report on the progress on computing the current maps from the magnetic induction in bulk samples of YBCO melt-textured compounds. Typical sample size is in the cm range and induction maps B-z(x,y,z) are obtained by Hall probe measurements. Currents are obtained by solving the inverse Biot-Savart problem. No assumption is required on the number of domains or geometry of the sample; the only constraint in the model is that the current circulation should be confined in the basal plane and uniform in the sample thickness. A current map with a resolution of 0.25-0.5 mm is typically obtained. Critical tests of the stability and accuracy of the current flow solutions have been performed. We have applied the algorithms to remanent flux maps obtained after both FC and ZFC magnetization processes. The algorithms can be readily used and thus can constitute a helpful tool for superconductivity engineers. The use of our software implementation is available free of charge at http://jaumetor.upc.es:8080/caragol. (C) 2002 Elsevier Science B.V. All rights reserved.