I spoke with my EE friend about this quite a bit and, without going into detail, we came to the conclusion that some of the energy absorbed by new load is intercepted from existing loss pathways, and some is taken from the power line. The proportion depends on relative position in space and the relative "impedances" of the various pathways.
Picture a steel bar held a given distance from a bar magnet, and you insert another piece of steel between them. What happens to the lines of flux through the original steel bar? Do they increase, or is some of the existing flux redirected to the new steel? We concluded that the answer is some of each, and feel the electric field behaves similarly.
We also believe that fluorescent tube doesn't light from electrical current inside, but from the phosphors being directly excited.
Close, but not 100%. I went back to one of my physics books. My "
caused by mag field" comment earlier was not correct.
There is a current that flows through the bulb. The only analogy I can give is like you taking a plastic straw that has tiny funnels on each end and placing it parallel to a running stream of water. The air gap resistance between lines and ground are some #, and now the bulb becomes less ohms over its length vs air of same length, etc. The electrons can more more freely through the bulb in that electric field, etc.
Inserting the bulb into the alternating high magnitude electric field causes electrons to flow through the bulb which hit the mercury gas atoms to excite them, and in that process (power line leakage current passes through the bulb) the ions (atoms) change electrical state and give off UV, that UV then strikes the phosphorus that is inside the bulb, the phosphorus is a catalyst which absorbs the UV energy and then gives off some photons in visible spectrum. That's how the light happens.
As for the power discussion. Since the whole process of mercury excitation and emitting photons in visible band does also include exothermic heat (aka energy loss), power is being used! The bulbs will likely shine brighter as the rel humidity increases.
The bulb in the E field is a small capacitor, thus it does change the impedance the source sees. The bulb has basically increased the leakage current by some small amount, etc. It's very analogous to your metal in mag field example, but in this case adding a metal rod (instead of bulb) in the E field will have same affect as bulb.
Not all energy dies a heat death. If I use it to elevate a mass it does not. If I use it to store energy in a molecular bond it does not (like manufacturing a product or similar). Some energy gets converted into other than thermal energy.
Almost all energy conversion involves heat energy which is typically lost from the system. The entropy of the universe is always (always) increasing.
