DETERMINATION OF 2-DIMENSIONAL CURRENT PATTERNS IN FLAT SUPERCONDUCTORS FROM MAGNETOOPTICAL MEASUREMENTS - AN EFFICIENT INVERSION SCHEME

An efficient inversion scheme is given to derive the local currents in a superconductor from the z component of the magnetic field measured above its surface, as is done using magneto-optical indicators. The me thod works for samples of arbitrary thickness provided that the curren t vector has only x and y components. Data storage is much lower and c onvergence much faster than in previously reported schemes. The influe nce of the distance of observation and of the sample aspect ratio on t he measured field H-z is investigated. The current calculated from the magneto-optical observation of a real sample (a Bi2Sr2CaCu2O8 single crystal) is in good agreement with the value measured directly by mean s of torque magnetometry.