my2cts. I'm also interested in the theoretical knowledge necessary to answer the question. I just meant that I expect practical details, and not only a long theoretical page of calculus. Regarding the plasma frequency, please assume what pleases to you if that can help to provide an example. Also, if this is a crucial point, what parameters should I tune to obtain a given plasma frequency.

Do you have reference for Einstein etc. supporting advanced waves? well regarded books? Also, have you succeeded in convincing a professor of physics about your article? I'm curious, but there are so many theories by persons that think they have discovered something, that turn out to be just big errors of understanding right the physics....

"If the real part of the power in coil 1 is positive, it indicates that energy is flowing in from coil 1. Coil 1 is now a primary coil. Otherwise, coil 1 is a secondary coil." +1 for this part. Regarding your article, it's hard for me to believe Maxwell's equations are inexact. But I'm not really a physicist, so good luck.

@Emilio Pisanty: I disagree with the fact that uniform charge densities are "as not physical" as point charges: the charge densities are defined by smoothing the microscopic charges by convolution with a Gaussian, leading to the macroscopic field which is smooth. Sure, the macroscopic field is a mathematical being, but it is real, just like the mean of your score in a competition is real.

I can't believe. I am currently writing an article with exactly the same title: the capacitance matrix revisited. This subject has hunted me for years. And now that I have set up all the material and begun to write, I discover you have published a similar article.

Yeah, I founded it in Griffith too since I posted this thread some years ago.

Michael. I cannot upvote this answer since it is partial and temporary, but thx.

But I think the simplest and the best answer is that of basics. Since it has been unduly downvoted, I demand other persons to upvote it.

So, you introduce electric charges inside an E field to be able to use a potential energy in the context of analytical mechanics during a brief time. You are a real fan of analytical mechanics, aren't you :-)

(at least if the wood rod is sufficiently heavy for the water friction to be negligible in first approximation)

@Kuhlambo. I can understand why basics feels bitter. If you have tried to experiment this case, I think the problem may be you have to be very careful about the way you apply the torque to the rod: fingers are not good. Maybe a wood rod immersed in water with 2 small propellers (mounted with an elastic) to create the forces F1 and F2 may give a better idea of what is going on.