Current Harmonics Versus Voltage Harmonics

The egg of a bird closely related to a chicken came first.

I have a different take. Harmonics is a natural occurrence with current. When current is established, a current M field is established. ANY change in current causes charge spin at that rate of change, this is the first spin. And that first spin causes repeated integer concentric spins. This is a natural current dynamic. Current is self reactive. Because it has electric charge and it has magnetic charge. E and M alignment.

Changing current has a longer path than steady current because of that spin. Changing current causes it's own delay. Because of that longer path. Multiple spins, multiple delays. But all in phase with first spin.

A cap(or opposite wound coil) inverts that spin. And can nullify that spin. Each spin has it's own impedance.

A coil can amplify and wind that spin and a cap can unwind and nullify that spin. And can frequency select a straight path for current. OR, equality of spin. Resonance.

A cap inverts, but also has spin. The opposite spin that is fed into it.

Charge alignment and charge spin is the true dynamic of current. Not the flow of it, it doesn't go far. Current is an intermittent flux. The flux alignment and rotation is the motion of current.....not the flow.

This is the way I see it. But most see it differently.

I presume that you are using the term "cap" to mean "capacitor". That is NOT necessarily obvious, especially to those whose first language is not English. A cap could well be a more-or-less cup-shaped object placed over an end of a coil, either conductive or not, ferromagnetic or not. There are undoubtedly other possible interpretations.

You've mentioned the spin concept quite a few times. I'm not quite in a position to say you're wrong, but I'm definitely among the "most", who see it differently.

You might see this for yourself, but it's messy. Make up a batch of ferrofluid and put it in a large flat pan/dish----work area. Use low freq AC-----1 to 15 Hz-----so your eyes can catch it. Place the circuit conductors in the fluid. You can also use DC and a series pot and turn it quickly to see this.

You can add a cap and coil in series above the fluid......and check out the spins on the input and output of the cap and coil. If you have an air cap, and air coil, submerge the entire circuit.

Design test circuit appropriately for test equipment.

A function generator or a 6-12 v battery should do. But the battery can supply more quick current without damage.

You might want to do this in the garage. It's a mess.

If one doesn't need a lot of convincing, one can watch youtube videos of this. Charge flow and charge formation on a wire. It spirals. It's twisty "torquey". A spring.