Dipoles, susceptibility

An electric dipole  est composed of two electric charges  -q et -+q set at a distance  λ: d=qλ . A magnetic dipole  est composed  of a small  loop of current I and of surface s: d=Isn, where n est la positive normal . The fields  of the two kinds of  dipoles are closely  similar.

The program, which  you may download, in its first  part, allows to compare  field lines from  differents dipoles et quadripoles (two identical neighbour dipôles) and  to vary their parameters.

In its second part, you may see and compare volumes, made of dielectric and ferromagnetic material, put inside an external  uniform field , so that they  are ensembles of dipoles. Charges and currents  neutralize themselves inside the volume, but not at its surface. . Resulting  fields are shown, with  their field lines,  together with surface densities of charge and current. Shown  volumes are: a sphere, an ellipsoid of revolution (rugby ball ) and a cylindric bar  of  finite length.

To get the executable, please click below: