Inversion calculation of two dimensional current distributions from their magnetic field

This is the authors' abstract. We don't add key points for this paper.

For nondestructive evaluation and geophysical explorations, e.g., with superconducting quantum interference devices, efficient inversion calculations are needed. A program has been developed to compute the current distribution in a plane from the magnetic field sampled in a parallel plane. The process uses an iterative matrix inversion for the relation between current and magnetic field (the Biot-Savart law). Examples of the determination of up to 100*100 current dipoles out of magnetic field components with different signal-to-noise ratios as a function of distance are presented. The efficient indirect inversion procedure for calculating currents of up to 100*100 dipoles requires about 1 h on a VAX 3100 workstation, even if all three components of the magnetic field are disturbed by noise and the distance between the field and current plane is large, corresponding to a normalized distance g=10.>