I've succesfully derived the symmetric Energy-Momentum tensor for electromagnetism in free space in SI units.

However, I find that while my expressions for the energy density etc are correct, I cannot then go on frrm there to derive conservation of energy and momentum. I was wondering if anyone knew which technique to use?

I have been using Classical Electrodynamics by Jackson and have taken his expressions in Guassian units and converted to the SI unit system.

This wikipedia article has the same results which I derived:

http://en.wikipedia.org/wiki/Electro...-energy_tensor

Does anyone have any suggestions as to how to proceed in proving conservation of energy and momentum?

Cheers, sox