Re: Sparks jumping from 4' to 9' (was Re: 20 joules)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Steve Conner <steve@xxxxxxxxxxxx>

> At a constant input voltage, it is probably not the
> interruption of the output that allows longer
sparks.

I agree. I think what happens is that the use of an
interrupter allows us to change the design such as to
push the output voltage a lot higher.

To take an example- My DRSSTC- which is pretty modest
as DRSSTCs go- delivers a 5.5J bang in 180us, so the
peak pulse power works out at 30kW. The output
voltage, as far as I know, is about 200-250kV. A
single one of these bangs produces a 22" spark, and
multiple bangs at 100Hz rep rate can jump up to 40".
The average power is only about 500-600W.

Now if I were to take the same coil and run it CW, the
average power would be around 30kW, and I'm sure I
would get a sheet of flame at least 40" :-o But the
little tabletop sized coil would try to draw 125A from
the line and self-destruct in a fraction of a second,
which is the point I'm trying to make.

High peak power is what makes long sparks. We design
the coil with enough peak power to produce the size of
spark we want, then use interruption to reduce the
average power to a manageable level that won't burn
anything out, without hurting spark length much.


Steve Conner