Calculating EM Force in the Electromagnetic Waves (emw) Environment

Hi,

This should be a very straightforward question. I would like to calculate the time-averaged electromagnetic force (via integrating the Maxwell Stress tensor over a surface). The fields that I need are taken from the Electromagnetic Waves (emw) physics environment. There is no node available for "Force Calculation", as there is in some of the AC/DC environments. However, I do see that I can perform surface integrations in post-processing and that I have access to the z-component, etc., of the Maxwell Stress Tensor. However, this is confusing to me, since there are only 3 components available and there should be 9 components of the Maxwell Stress Tensor (it's a 3x3 matrix). Moreover, I was wondering if the integration is considering the surface normal of the surface of interest. I am interested in doing this for both a 3D case and a 2D axially-symmetric case.

So then, two main questions:

1) Why are there only 3 components available for the Maxwell Stress Tensor?
2) I would like to calculate the force using the Electromagnetic Waves (emw) environment. Can I do this?

Thanks for your help,
Brian