IEE ring problem

["ahmad_m_eid" <ahmad_m_eid@xxxxxxxxx>]

Dear all 

I used FEMM in solving the attached ring problem.
the attraction force I get is about 20 mN while the actual attraction
force is 76.5 mN.

I used Lorentz and Maxwell tensor they give nearly the same answer
around 20 mN.

I attached the problem and my solving in another email.
Please comment on this problem.

the problem found in :
A. Benhama et all.," force and torque computation from 2D and 3D
finite element field solutions", IEE Proc.-Electr. Power Appl., vol.
146, No. 1, 1999. 

thanks a lot
ahmad