Tesla had a circuit which discharged a capacitor through an inductor and a spark gap. This produced a Plasmoid, which is a type of plasma which is magnetized. He didn't have semiconductors, so he used a magnet to blow out the spark and the pulse frequency was a result of the strength of the magnet. Low frequencies produced physical vibration of objects and a painful sensation, but pulses shorter than one tenth millisecond were harmless. This energy is a form of static and won't short out in water, so a light bulb can be put under the water.
With the fluorescent tube, the energy is coupled through an rf effect. And just for fun I'll point out that a CFL has a type of bifilar winding, in the shape of the glass. This single layer winding is bidirectional.
With the VIC, the capacitance is built in, due to the capacitance between the layers of the coil, and even the spacing between the windings of each layer. Increasing this capacitance is why I like to use wax paper and lacquer between the layers. Also to insulate against high voltage puncture.
Tesla called his energy paramagnetic. I've shown that water will repel or attract a Plasmoid, depending on polarity.
