Master Ivo posted an interesting video this morning. text from the video:
"This experiment with 3 bifilar coils shows a disruptive discharge right BEFORE the pulse turns on. But why is it happening at that point in time? C2 (20nF) is tuning the L3 coil to resonate to the pulses of L1. L1 produces inductive spikes, captured vis the diode, into C1(220nF) and L2. All coils are bifilar Tesla pancake coils, each 0.7 Ohm 0.31mH"