8000FPS Slow Motion Tesla Coil Spark Formation and Collapsing Hot Spots

[Mads Barnkob]

Slow motion Tesla Coil recordings of SSTC sparks. Recorded at 8000 frames per second and replayed at 15-30 frames per second. Notice the step leader, known from natural lightning strikes and the hot spots that might be forming from collapsing plasma channels.

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What do You think about the hot spot from collapsing plasma channel idea/theory?

[Uspring]

The initial long spark is quite puzzling since I believe it to require lots of voltage and power. I don't know, where that could come from since you are using mains ramped power input, which should be low between pulses. It would be interesting to see scope shots which give some indications of power input like e.g. current of the primary or secondary (base).

Interesting is also your second observation. Since the hot spots seem to localise around sharp bends, I think they could be the result of parts of the arc warming each other. Air thermal conductivity limits the temperature that the arc can obtain and cooling works less well if there is hot air around.

[Mads Barnkob]

The initial long spark is quite puzzling since I believe it to require lots of voltage and power. I don't know, where that could come from since you are using mains ramped power input, which should be low between pulses. It would be interesting to see scope shots which give some indications of power input like e.g. current of the primary or secondary (base).

Interesting is also your second observation. Since the hot spots seem to localise around sharp bends, I think they could be the result of parts of the arc warming each other. Air thermal conductivity limits the temperature that the arc can obtain and cooling works less well if there is hot air around.

Initial break down of air from the topload capacitance being shot off and then we have the recharging of topload/pumping of energy throughout the primary pulse length? I would have to do it on another coil, I do no longer have this particular coil available.

"Plasmoids" was suggested on Youtube or Facebook, but that is a theory made for stuff happening in space

[Uspring]

Initial break down of air from the topload capacitance being shot off and then we have the recharging of topload/pumping of energy throughout the primary pulse length?

Yes, something like this. But that would require some energy supplied to the coil initially and quickly. QCWs don't work like that. Perhaps you have some smoothing caps, which have some charge left between half waves, which happens if you turn the interrupter off between half waves. The flash would then occur, when you turn the interrupter on. I'm just speculating here.