Dear Mark,

    All materials will be saturated with flux density above 3 T. So I presume the core permeability is 1 (like in the air, wood, aluminum,..).  So that device is a coil: some core with a winding (please see the picture attached).

    At the horizontal axis the force will have only X-component. But if the particle is placed outside the axis - it will be pulled to the nearest pole.
    The Fx distribution is represented in pdf file.
    
    Time spent: 1 hour.

Best regards,
Alex



Dear Alex,

           After you solve the previous problem with 3x 7T magnets, Kindly solve this. This is a single large magnet horse-shoe model electromagnet. We will see what happens to the magnetic nanoparticle placed at the centre of the field as shown in the diagram attached to this mail, or if required the particle can be placed at 10 to 15 cm location from North or South poles.
           This is a horse-shoe magnet and I hope you can work on this model. 

with regards,
Mark