Lightning and tesla coil discharges are very diffe...

2007-10-17T05:42:00.000-07:00

Lightning and tesla coil discharges are very different things. About the only thing in common is that they are both electrically induced air plasmas.

Lightning is a pulsed DC current, produced when volumes of electrostatically charged atmosphere discharge to ground (or to another area of opposite charge.) A lighning 'strike' is usually one or more very brief, high current pulses in very quick succession. Usually too closely spaced to differentiate by eye, but sometimes you'll see a lighning bolt 'flicker' - you are seeing successive strikes along the same (or nearly same) ionisation path.

Tesla coils are high frequency AC resonant transformers, and the arcs are thus high frequency AC, with broad spectral content up into the Megahertz range due to the ringing square wave primary coil excitation. As a result, the visible behavior of tesla arcs is quite different to lightning. The processes in action are too complicated to explain in detail here, but the dominating ones are: point discharge, skin effect, persistence of ionization paths in air, charge mobility in air within the HF electric field surrounding the tesla coil head, and distortions of the field due to active plasma paths. Which all intereact to produce the 'bushy' spreading arc tangles typical of Tesla coils.

But, to address b. durbin's point, lightning (mostly) converges, but tesla arcs do actually diverge into the space around the coil, unless a single, direct arc forms to some nearby ground point. Its an AC current, and there is a single field source - the coil head. Hence, 'diverge' is a fair description.

Btw, the photo of Tesla surrounded by arcs is a double exposure he arranged. Documented, sorry don't have ref handy.

TerraHertz

Me neither. Great but dangerous experiments.

2007-08-17T05:54:00.000-07:00

Me neither. Great but dangerous experiments.

fascinating comment... I did not know this.

2007-08-16T19:57:00.000-07:00

fascinating comment... I did not know this.

Interestingly, lighting does not fork; it converge...

2007-08-16T19:19:00.000-07:00

Interestingly, lighting does not fork; it converges. The Tesla coil is, then, the terminus of the lighting, not the originator as you might think.

I learned this from a meteorological friend of mine. He said that almost all of the lightning strikes we see photographed are ground-to-sky lightning; the true sky-to-ground bolt is very rare.

Comments on Dark Roasted Blend: Tesla Power in Your Backyard

Lightning and tesla coil discharges are very diffe...

Me neither. Great but dangerous experiments.

fascinating comment... I did not know this.

Interestingly, lighting does not fork; it converge...