Magnetic levitated electric wire

[AHashemi]

Hi
I'm thinking about making an instrument to show the force on a wire carrying electric current for students in lab. A normal wire which levitates from ground after it has current flowing in it.

We have the following equations

F = ILBsin(a)
W = ALg

'A' being the mass of unit length of the wire. We will make the magnetic field perpendicular to the current flow so a=Pi/2 and sin(a)=1 and I want the wire to be suspended above the ground so in equilibrium we must have:

F = W
ILB = ALg
IB = Ag

Since g and A are constant in this device what I will need to do is playing with magnetic field and electric current.
I'm not very familiar with the Earnshaw theorem but I know if I use an AC current this is doable. I can use normal power outlets (220 V in this case) but I don't know how to create the uniform magnetic field needed. Are natural magnets (Like Neodymium magnets) better or a magnetic field generated by another wire or coil?
Is there any easier way to do this?
What are notes to keep in mind in this experiment?

 

[vanhees71]

If you want a homogeneous magnetic field, search for Helmholtz coil:

https://en.wikipedia.org/wiki/Helmholtz_coil