An analytic model for the fluxgate magnetometer

The output voltages from various fluxgate probe types are found to have the same general form, and an analytic model has been developed with which the output may be calculated. In the saturation region where the output pulse is developed, the differential permeability can be closely approximated by an exponential, , where k1and k2are on the order of 100 and -2.0, respectively, for cores of Supermalloy or Permalloy 80. Using this model, the effect of the nature of the excitation function on output pulse amplitude and width and the effect of the squareness of the core characteristic can be clearly demonstrated, and good agreement with experimental results has been obtained.