Magnet (unidirectional): linear approximation


This model ( Linear magnet described by the B r module ) defines a B(H) dependence of linear demagnetization.

Main characteristics:

  • the mathematical model and the direction of magnetization are dissociated
  • a single material for description of several regions

Mathematical model

In the direction of magnetization the model is a straight line .

The corresponding mathematical formula is written as follows:

B//(H)= μ0μr//H//+Br


  • μ0 is the permeability of vacuum, μ0 = 4 π 10-7 H/m
  • μr// is the relative permeability (recoil line slope)
  • Br is the remanent flux density T
The shape of the B(H) dependence in the direction of magnetization is given in the opposite figure.

In transversal directions one can write:

B(H)= μ0μr⊥H

where μr⊥ is the transverse relative permeability (μr⊥ = μr//)

Direction of magnetization

The direction of permanent magnet magnetization is “dissociated” from the model. In the software, it is defined separately.

The various possibilities available to the user are shown in the table below. (The basic plane is a plane XOY.)






Orthoradial positive Orthoradial negative

CR is the radiality center.