Response to a Dipole Magnetic Field of a Magnetic Sensor with a Finite-Length Magnetic Core

Abstract

A simple method was developed for using the resolution of a magnetic field sensor with a finite-length thin magnetic core in order to assess its ability to detect a tiny magnetic dipole source. The values of the total linkage magnetic flux to the core in a uniform magnetic field and in a dipole magnetic field are compared to determine the detectability of a tiny magnetic dipole source. For a given geometry of cores and a dipole source, the magnetic flux densities in a thin core are calculated numerically by means of a FEM package. For a given fluxgate magnetometer with the resolution characterized in the uniform magnetic field, one can tell whether or not it is possible for the magnetometer to detect a given tiny magnetized sphere within the limit of allowable access to the target.