Re: Two Manifestations of Charge

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Dave,

For the picture at:

http://www.tesla-coil-builder.com/images/chiron01twosparks.jpg

I think the copper ball is the HV top terminal of your flat coil, there is 
a ground wire about three inches higher and the end of the florescent tube 
is between them.

Your hand appears to be a ground point as well but there is glow on the 
other side of the tube as is common with hand held tubes...

The question is why does the top spark appear to flow more current than the 
lower spark.

The problem is we don't know the voltages of the tube end.  Since the tube 
has significant voltage across it, it would appear that the voltage at the 
end of the tube is near that of the copper ball, but both of them are at a 
far higher voltage than the ground wire.

In this situation, a significant current flow would be going from the shaft 
of the tube to the coil too (our old pal, displacement current).

So the current in the bright spark goes to both the smaller sparks to the 
copper ball and to the coil from the shaft of the tube through capacitive 
coupling.  The wire is also a sharp point with one arc where the ball is 
spreading the arcs over a wide area.

You need to eliminate all the odd stray currents that the long tube is 
causing!  Styrofoam would be a good replacement since it is very non 
conductive and has a dielectric constant nearing 1.  You could still use a 
metal tip (from a broken tube) at the end of a foam rod now so that part 
could stay the same.  You should also use a tiny wire on the copper ball so 
that arcs are from a point like the ground wire.

If these changes are made, I think both the top and the bottom are will be 
the same.

Cheers,

        Terry


At 07:31 PM 7/2/2005, you wrote:
> > Original poster: Steve Conner <steve@xxxxxxxxxxxx>
> >
> > >In between the spherical top load and sharp pointed ground
> contact, I
> > >placed the butt of a fluorescent tube.  When the coil fired
> up, there
> > >was a thick white spark from the ground to the tube and a thin
> purple
> > >spark at the same time between the sphere and the tube.
> >
> > Was either end of the secondary coil connected to another
> > grounding point (water pipe, green wire of AC outlet,
> > whatever)?
>
> Yes, the secondary and primary ground were both connected to
> Earth ground, which is a 3/8" aluminum cable leading to a copper
> cage 17 feet deep in my cistern.
>
> Have you tried to produce the two distinct types of charge on
> your coils?  I would think this is a good project for Tesla
> coilers.  We spend big bucks honing in on length, but how much do
> we know about charge quality?  What exact conditions produce
> thick white sparks as opposed to thin purple sparks?  And why can
> these two separate manifestations exist in the same coil and in
> the same gap between the ground and top load?
>
> As I pointed out in another reply, I have also built a stand for
> the tube out of PVC plastic, with no ground to the tube.  The
> same phenomenon results.
>
> Dave