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Re: stepped leaders

Tesla List wrote:
> 
> >From MALCOLM-at-directorate.wnp.ac.nzMon Sep  2 11:45:03 1996
> Date: Mon, 2 Sep 1996 14:36:17 +1200
> From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
> To: tesla-at-pupman-dot-com
> Subject: Re: stepped leaders
> 
> Hi Jim,
>         You asked....
> 
> > Could I interject a thought on this condition? Under this condition,
> > the TC secondary IS acting like an unterminated transmission line with
> > the attendant high SWR that this condition implies. (Standing Wave
> > Ratio can be thought of as the ratio of forward power to reflected
> > power) With no load at the end of the transmission line (no sparks at
> > the discharge terminal) and all the power sent down to the far end of
> > the secondary is reflected back to the near, driven, end.
> >
> > This reflected power is transformed by the transformer action of the
> > TC secondary to TC primary coupling and is dissipated in whatever
> > lossy components are in the primary circuit. Given most construction
> > methods used by the coilers on this list, the primary is of low R, the
> > cap is of low D, that leaves the spark gap as the losseist component.
> > It starts dissipating the power of the system.
> >
> > One of my unanswered questions: is the output voltage of the TC
> > secondary: a) strictly the input voltage multiplied by the turns
> > ration of the secondary to primary? b)input voltage multiplied by the
> > turns ratio multiplied further by the 1/4 wave transmission line
> > properties of the secondary? or c)some combination?  I am waiting to
> > measure this until I can build some type of metering scheme; field
> > mill or HV resistive divider.
> 
> I'd like to inject a note on this. First off, turns ratio is out. It
> applies only when the coupling approaches 1. Wave action governs
> secondary behaviour IMO. The easy way is thinking about the bathtub
> scenario, where you give a wavefront sloshing between one end and the
> other a timed push at one end at the exact time it is starting to
> head up the other end again. In this system, energy accumulates with
> each push in exact proportion to the push imparted. In principle, you
> can give it any number of pushes and it gets higher and higher. In
> practice, it is going to reach an amplitude where some of it starts
> spilling over the edge (energy loss - spark). If this didn't happen,
> there is no theoretical limit to how high it reaches as long as the
> push is enough to overcome any loss with a bit to spare. The losses
> may grow with amplitude (e.g. dielectric losses) so what started out
> as an adequate push ends up being inadequate to over come these
> losses and the system reaches equilibrium.
>      Now for the fly in the ointment re our cap discharge systems.
> The push per cycle is not constant! It is in fact a decrementing push
> (primary ringdown). You can see that the energy accumulated in the
> secondary can only reach the level of that originally in the primary
> cap if no losses exist (gap ruins that ideal). It is easy to see that
> the voltage in a cap discharge system has a very real limit and that
> limit is the amount of energy originally contained in the primary cap
> (minus losses in getting it transferred to the terminal). This is the
> real scenario.
>      **Speculation**  In fact it's not even that good. The line is
> less than a wavelength long, so energy is distributed along it. In
> fact you can estimate terminal energy in a "full" line by using the
> ratio of the two capacitances (line and terminal). If they are equal,
> the energy distribution must be equal. ** End Speculation**



Nice speculation, I like it.  It needs testing though to a more critical 
degree.  I would tend to think that within the limits of coupling and 
loses (which are always high in a Tesla coil), the energy is distributed 
evenly any way.  It is just a matter of what form you want the output or 
usable energy to be manifested as!  If a large terminal cap is used, it 
is elerostatic or varying E-field energy and with the coil C (line) 
predominating it is EM which predominates.  (also speculation)
R. Hull
>    big snip



> Sorry for shouting. I firmed up on these suspicions during my
> experimental period in the weekend. I think it is clear why Tesla
> claimed that "no such pressures, even in the remotest degree" could
> be obtained from lumped circuits. I think it is also clear that the
> line can only accumulate as much energy as there is available to
> drive it.
> 
> Malcolm