Incidentally, I forgot to say in my comments to drawings for Wakefield 4 that wherever and whenever (spatially and temporally) we have a zero potential in the waveforms, it doesn’t mean the energy current drops to zero there and then. No! Energy current there is in magnetic H rather than electric E form. For example, when the switch is being connected short, the voltage drops from 7V to 0V. That’s where and when energy current changes it’s presence from E to H. But it carries on without loss (we assume lossless Tx line).
So, the above fact does only enhance the statement that the content of the capacitor is dynamic. We have spatio-temporal changes of the entire ExH content.
Here is a hopefully useful analogy:
Energy current is just like a rotating ribbon which in some points in time passes some points in space vertically but then turns to the horizontal plane and vice versa. When this cap (Tx line) was charged uniformly to 7V the entire ribbon was moving vertically. When we jammed it by short-circuiting the switch, it had to turn to horizontal in order to pass through our jam. In other points (A,B,C) it began to vacillate from horizontal to vertical and back.
But in order to vacillate it had to move and rotate like a conveyor ribbon inside the cap. With the switch being turned ON, we don’t push the ribbon forward we only jam it! It doesn’t need to be pushed. It has its own drive at the speed of light in the medium!
An interesting experiment would be to modulate the switch with some ON/OFF duty cycle!