A NEW ANALYSIS OF THE INTRODUCTION OF THE MAGNETIC FIELD STATE QUANTITIES IN SOLIDS

Abstract

The introduction of the primitive magnetic field state quantities on a macroscopic and a microscopic scale is achieved by thought experiments. A comparison is made between the introduction of the macroscopic quantities via a direct procedure and via the average of the microscopic values. The average of the microscopic quantities is performed, in the known works, by the calculation of the average of the microscopic electric current density in the right-hand side of the law of magnetic circuit or of the Amp\`ere theorem, and then the average of the vector curl of the left-hand side is expressed. This indirect derivation involves certain difficulties. In the present work, a direct deduction is used by calculating directly the average of the primitive magnetic field state quantity. For this purpose, two physical models have been proposed: the elementary magnetic dipole model and the elementary solenoid model. It is shown that the average for the former model gives the macroscopic field strength, whereas the average for the latter gives a quantity proportional to the magnetic induction.