1. A method of determining an anhysteretic B-H characteristic of a material utilizing a primary coil and a secondary coil wound around a test sample of the material, comprising: holding the test sample in a test fixture with the primary coil and the secondary coil wound around the test sample; introducing a range of electric current through the primary coil and electronically recording the primary coil current and resulting secondary coil voltage over time; determining a measured magnetizing flux linkage versus primary coil current characteristic values for the sample from the recorded primary coil current and secondary coil voltage; establishing an expression for predicted magnetizing flux linkage incorporating spatial variation in the magnetic field intensity within the sample and based in part on anhysteretic magnetic properties of the material; and utilizing said expression to obtain values of characterizing parameters that cause a curve to fit within said measured magnetizing flux linkage versus primary coil current characteristic values, wherein said anhysteretic B-H characteristic is defined by said characterizing parameter values.