Re: [TCML] Re: Slo-Mo Videos of Tesla Coil

[jimlux <jimlux@xxxxxxxxxxxxx>]

Greg Leyh wrote:

> Hi Bert,
>
> I remember reading that an arc discharge maintains a roughly constant 
> current density as it grows.  

That's for a steady state arc. It grows to keep the center core at 7000K 
or so, which is where the conductivity greatly changes due to thermal 
ionization. If the internal temp grows higher, it expands and cools 
(more surface area for radiation loss).  Since the energy loss is 
probably dominated by radiative losses, which go as T^4, it's a pretty 
strong effect.

I don't know that a typical individual TC spark lasts long enough to 
reach steady state, though.


This implies that a higher current arc
> would leave a larger diameter column of hot air in its wake.  Given the 
> squared/cubed cooling effects on the hot air channel, would you imagine 
> that a coil that launches higher current arcs might have a lower optimum 
> BPS for arc length vs. power?   GL
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