Stephen A. Lawrence wrote: > The E and B fields together form a rank 2 tensor (the "Faraday" > tensor). The application of that tensor to a charged particle's > 4-velocity yields the 4-force on that particle due to the EM field. > Changing FoR changes the components of the Faraday tensor but doesn't > change the effect it has on a particular object.
This seems like a correct way of looking at the problem. Aren't you agreeing with my original point that the statement "magnetic fields never do work" is really not helpful in understanding electromagnetic forces. In commercial finite element analysis software forces are commonly calculated by using changes in magnetic field energy with position without any reference to electric fields. Do we need to change the way engineers think about these useful techniques. So where does the energy come from? Do you agree with my statement that it comes from both the ring and the dipole or do you say it all comes from the ring. George Holz Varitronics Systems
