How does Ansys Maxwell compute the surface and volume force density?
The way that Ansys Maxwell computes the surface and volume force density is described in Maxwell Help > Maxwell Coupling > Maxwell Harmonic Force Coupling > Force Density Calculation. You can find documentation here.
Fx,Fy, Fz are the force at the indicated direction (x, y , z).
Mag Force = sqrt ( Fx^2 + Fy^2 + Fz^2 )
In cylindrical coordinate systems, the force needs to be calculated using the Fields Calculator. In this case, the direction is specified in Vector / Scal? / Scalar X.
In cylindrical coordinate systems, the equivalence is:
X -> Radial
Y-> Phi
Z -> Z
The Mag Force is calculated using the equation described above, but it is based in the cylindrical coordinate systems.