Maxwell Stress Tensor

Hello all,

I'm new to Comsol and Im having a little difficulty getting my head around how the Maxwell Stress Tensor operates. I understand its operation when applied to parallel wires (Like in the example given in Comsol) but when I try to use it for my own model I don't understand it's behaviour.

I'm currently using Comsol to look at the scattering of electromagnetic waves from a dielectric sphere. I also want to look at the forces on the sphere.

All I've tried to do is to add a line integration, with the surface of the sphere chosen as the line, and then there is an option to get the upward and downward Maxwell Stress Tensor.

This gives me a complex result which doesn't make sense to me. Perhaps my understanding of the problem isn't complete? Is there a better way to work out the force on the particle?

Any help would be greatly appreciated!

Thanks,
Mark.