In electrodynamics, the phrase "in the absence of static and moving charges" refers to a scenario where magnetic effects are analyzed without the influence of excess electric charges or currents. This context is crucial for understanding magnetostatic material effects, as excess charges would introduce electrostatic phenomena and excess currents would create additional magnetic fields. The discussion highlights that while permanent magnets contain moving electrons, their overall charge and current are effectively neutralized at the macroscopic level. Consequently, the relationship B = μ(H) applies, where B is the magnetic field, μ is the permeability, and H is the magnetic field strength, under these idealized conditions. This approach simplifies the study of magnetic materials by isolating their inherent magnetic properties from other electromagnetic influences.
