I come back to the magnetostatic module (of FreeFem) and i discovered a residual error too much high for an another problem that i’m working on.
An analytical formula give the field at the center of the coil:
Bcenter = Jfil* (asinh((2* Rext)/length)/2-asinh((2* Rint)/length)/2)* length* u0
Jfil=5E6 A/m^2 , length=1 ; R1=0,1 m R2=0,2 m , Bcenter = 0.601128704 T
But with my files, i have still an error of 1-4% except if i increase drastically the mesh with more than 700 000 tetrahedrons and it take time to solve.
Could you give me any advice to decrease the error ? I would need something inferior to 1E-5 in relative.