Retrieving "Geomagnetic Survey" from the archives

Cross-reference notes under review

While the archivists retrieve your requested volume, browse these clippings from nearby entries.

1. Magnetometer

   Linked via "geophysical surveys"

   The fluxgate magnetometer is an active device that operates based on the non-linear behavior of a ferromagnetic core when driven by an alternating current (the excitation field). When an external static magnetic field is present, it causes an asymmetry in the core’s hysteresis loop. This asymmetry results in the generation of even harmonics in the core's magnetization response. The amplitude of the second harmonic ($2f$) is directly proportional to the component of the e…