In his 1890's Lectures and his radiant patents, Nikola Tesla always talked about Impulses.
These where key for his radiant energy effects.
Instead of magnetic induction, he used dielectric induction,
which is also used by Maxwell to explain how capacitors can conduct current.
The displacement current, is what flows through the dielectric material.
It is not a conventional current which is bound to a conductor.
Instead it flows through a so called isolator. Like the earth is.
This is what Tesla used. Tesla currents are Displacement currents. Induced by rapid changes in voltage, which were the impulses he used.
He talked about current impulses and voltage impulses.
Current impulses are created from capacitor discharges.
While voltage impulses are created from coil discharges.
The displacement current created by the voltage and current impulses are different.
A voltage impulse of a coil is bidirectional
While a current impulse from a capacitor is unidirectional
So an impulse in the primary can induce resonance in the secondary, by dielectric induction.
Dielectric induction, from rapid high voltage changes, follows different natural laws than magnetic induction
better explained in this video:
https://youtu.be/YnijhZdAseA