# About magnetic force formulae<br/><br/><br/><br/>

Saturday, November 6, 2004 - 4:30pm - 5:00pm

EE/CS 3-180

Anja Schlömerkemper (Universität Stuttgart)

The formula for the magnetic force that is exerted by a magnetic field on a single magnetic dipole is well accepted. On the other hand, the formulation of magnetic force formulae for macroscopic magnetic systems has been under debate for a long time. A final answer to this question is of interest in the context of deformable magnetic bodies as for instance of ferromagnetic shape memory alloys.

In the first part of the talk, a brief overview of Brown's [1] approach is given and related work that was initiated by Brown's approach is mentioned.

Secondly, we focus on the formula for the magnetic force between rigid magnetic bodies which was derived from a lattice of magnetic dipoles in a continuum limit [2]. The main ideas of this approach and of the mathematical proof are presented. In addition to the classical magnetic force formulae, one obtains a surface force density which depends on the underlying lattice structure and includes short range contributions of the magnetic interaction at interfaces.

In the final part of the talk we address the question of whether this magnetic force formula describes nature well and compare it with Brown's formula.

[1] Brown, W.F., Magnetoelastic Interactions, Springer-Verlag, Berlin, 1966

[2] Schlömerkemper, A., Mathematical derivation of the continuum limit of the magnetic force between two parts of a rigid crystalline material, accepted for publ. in Arch. Rational Mech. Anal.

In the first part of the talk, a brief overview of Brown's [1] approach is given and related work that was initiated by Brown's approach is mentioned.

Secondly, we focus on the formula for the magnetic force between rigid magnetic bodies which was derived from a lattice of magnetic dipoles in a continuum limit [2]. The main ideas of this approach and of the mathematical proof are presented. In addition to the classical magnetic force formulae, one obtains a surface force density which depends on the underlying lattice structure and includes short range contributions of the magnetic interaction at interfaces.

In the final part of the talk we address the question of whether this magnetic force formula describes nature well and compare it with Brown's formula.

[1] Brown, W.F., Magnetoelastic Interactions, Springer-Verlag, Berlin, 1966

[2] Schlömerkemper, A., Mathematical derivation of the continuum limit of the magnetic force between two parts of a rigid crystalline material, accepted for publ. in Arch. Rational Mech. Anal.