CONJUGATE-GRADIENT ANALYSIS - A NEW TOOL FOR STUDYING SATELLITE MAGNETIC DATA SETS

Conjugate gradient and sparse matrix techniques are utilized in the so lution of a geomagnetic inverse problem. Global crustal data, sets col lected from low-earth orbit are quickly inverted (using a design matri x approach) or continued to a common altitude (using a normal matrix a pproach) even when using parameterizations of 10000 or more dipoles. T he sparsity results from the rapid decay of the magnetic field with di stance from the dipole. Iterative techniques such as the conjugate gra dient save computer time and space when compared to more direct approa ches using the Householder transformation, thus allowing problems that were intractable to all but the largest supercomputers to be performe d on workstations of only moderate power.