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30 BPS, 60 BPS tests
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From: Bert Hickman [SMTP:bert.hickman-at-aquila-dot-com]
Sent: Thursday, March 19, 1998 7:07 AM
To: Tesla List
Subject: Re: 30 BPS, 60 BPS tests
Tesla List wrote:
>
> ----------
> From: Jim Buck [SMTP:jimbuck1-at-bellsouth-dot-net]
> Sent: Tuesday, March 17, 1998 5:11 PM
> To: Tesla List
> Subject: Re: 30 BPS, 60 BPS tests
>
> Tesla List wrote:
> >
> > ----------
> > From: Bert Hickman [SMTP:bert.hickman-at-aquila-dot-com]
> > Sent: Tuesday, March 17, 1998 9:07 AM
> > To: Tesla List
> > Subject: Re: 30 BPS, 60 BPS tests
> >
> > Tesla List wrote:
> > >
> > > ----------
> > > From: John H. Couture [SMTP:couturejh-at-worldnet.att-dot-net]
> > > Sent: Tuesday, March 17, 1998 12:36 AM
> > > To: Tesla List
> > > Subject: Re: 30 BPS, 60 BPS tests
> > >
> > > At 12:16 AM 3/12/98 -0600, you wrote:
> > > >
> > > >----------
> > > >From: Robert W. Stephens [SMTP:rwstephens-at-headwaters-dot-com]
> > > >Sent: Wednesday, March 11, 1998 12:27 PM
> > > >To: Tesla List
> > > >Subject: Re: 30 BPS, 60 BPS tests
> > > >
> > > >> From: John H. Couture [SMTP:couturejh-at-worldnet.att-dot-net]
> > > >> Sent: Monday, March 09, 1998 11:22 PM
> > > >> To: Tesla List
> > > >> Subject: Re: 30 BPS, 60 BPS tests
> > > >
> > > >John Couture wrote:
> > > >
> > > >> Because the TC system contains capacitors it has the ability to store
> > > >> electrical energy over more than one spark gap operation. This means the
> > > >> electrical energy can build up in the secondary circuit and provide one
> > > >> extra long random spark. This type of operation is obvious because the
> > > >> random sparks emitted from the secondary terminal are not of the same length
> > > >> indicating different amounts of voltage and energy on the secondary terminal.
> > > >
> > <SNIP>
> >
> > John,
> >
> > Sorry - I've got to agree with Malcolm and Rob here...
> >
> > With the base of the secondary coil grounded, a typical coil/groundpath
> > resistance of less than 1 kOhm, and typical coil and terminal
> > capacitance of 50 pF, the amount of time that any residual static charge
> > to fully dissipate would be a maximum of 250 nSec. The bang-to-bang time
> > is about five orders of magnitude longer than this... No residual ES
> > change will be there. Other gas-discharge phenomena under repetitive
> > sparking conditions are much more probable explanation for varying
> > spark length...
> >
> > -- Bert --
>
> After reading this thread for a while I just wanted to throw in my 2
> cents worth.
>
> Couldn't varying spark length be due to simple observable things? If a
> spark has fewer smaller branches doesn't the extra energy remain in the
> main spark channel? Also what about when a spark straightens out? And
> finally if the voltage rises and the current drops (same energy) doesn't
> the spark get longer and thinner?
>
> Jim Buck
Jim,
Varying spark length may be caused by a lot of parameters interacting
chaotically and non-linearly with one another. Optimally-quenched and
capacitively top-loaded disruptive coils seem to have an output voltage
characteristic that's ideal for supplying heavy current to an advancing
streamer during ring-up. Combine this with a rep-rate that permits
partial re-use of the arc-channel blazed by the previous bang, and you
now have the recipe for streamer growth on successive bangs.
Eventually, a balance must be reached between power dissipated in the
entire streamer versus the effective power supplied from the coil's
output. At any given time, the streamer's length will be strongly
dependent upon streamer root peak temperature, previous streamer length
and "sinuosity", and a whole host of other factors. Because of negative
resistance characteristic, higher current flow will tend to make the
plasma better conducting, allowing the potential of the discharge
terminal to extend "further out". The important thing is that the length
of a given streamer will be a function of the past history of the
channel even though the electrical events ("bangs") are independent from
one another. To my knowledge there are no measurements of output voltage
which have indicated the presence of any DC voltage between "bangs".
This does not say that there aren't a whole lot of left over ions in the
immediate vicinity of the coil...
-- Bert --