Faraday magnetometer with polar hemispheres: Stability zones for measuring of magnetic susceptibility of particles

Abstract

The polar hemispheres proposed for use (in Faraday magnetometer) are accompanied by the families (for the different values of the distances between the poles b) of the coordinate characteristics of the field induction B, the gradient gradB and the magnetic force factor BgradB. According to the conditions of placing the study sample and based on the example of polar hemispheres with the diameters of 100 mm and 135 mm, the dependences on the effect of b on the values of the coordinates of the xextr extremums of gradB and BgradB parameters are obtained when measuring pondermotive force, in the vicinity of which those parameters are stable (approximately constant). Moreover the characteristics of B are obtained for three coordinates: longitudinal x (along or parallel to the line of action of the ponderomotive force) and transverse y and z (for values of x in the vicinity of the extremums of ∂B/∂x and B∂B/∂x). It allowed to prove the possibility of simplifying of the gradient stability zones and the force factor (as 3-dimentional micro-objects) is substantiated. It is shown that within the stability zones of the parameters ∂B/∂x and ∂B/∂x the partial derivatives ∂B/∂y and B∂B/∂z can be neglected, assuming that ∂B/∂x ∼ dB/dx ∼ gradB.It was registered that the possibility of manifesting the stability zone of the force factor is excluded in the Faraday magnetometer with mutually nonparallel coils (to obtain the stable gradient zone for certain values of the coils size and the angle between them); and the prerequisites for the manifestation of a stability zone for the gradient and the force factor in the magnetometer with a permanent magnet are absent.