# RE: Coherence ?

```Hi Will,

> Original Poster: "Payne, Will E" <will.e.payne-at-lmco-dot-com>
>
> Malcom,
>   Although I'm still a bit fuzzy on the theory related to this thread,
> perhaps my meager understanding of RF theory will help.  If the voltage
> along the secondary is redistrubuted, then the current also will be.  It may
> be easier to instrument a secondary with current probes along its length and
> look for such a redistribution of energy.  At first blush the idea of
> voltage distrubution changing from linear to another distribution seemed
> impossible, but after considering the math from a few different
> perspectives, it seems more plausible to me.
>   The impulse nature of TCs impose boundary conditions I am not accustomed
> to solving, but here goes:  Let us ssume for simplicity that a helical
> resonator is shock excited by a uniform flux U(2) unit function arriving at
> t=0.  The linkage equation implies the initial boundary condition is the
> voltage gradient along the resonator is linear at t=0.  The other boundary
> condition, at t=inf,  an unloaded lossless resonator will have a voltage
> distribution of sin(wt)/cos(x).  A believe it could be derived that a loaded
> lossy resonator will approximate this distribution as it decays to zero, but
> our practical experience leads us to believe something similar to this
> simplistic model actually occurs.  Therefore the Corums may be right.
>    Bear in mind I have not read these controversial authors' papers, and
> please excuse this TC novice if I have totally misunderstood the questions
> in my attempt at a theoretical treatment.  I am grateful for the posts of
> you and all the experienced coilers out there, your patience and willingness
> to help us novices is invaluable.

I think you are correct with caveat: the secondary is not shock
excited in a TC. It is driven at Fr by the primary. Richard Hull's
thyratron experiment is close to shock excitation but that is not the
mode we normally use as our systems are not normally built to operate
like that.
My personal thinks is that the spectral analysis as produced by
the classical TC system has been misinterpreted. I think it is more
accurately viewed in the time domain where one can see the time-
related dynamics occurring. If one accepts this interpretation as
being correct, there is an immediate answer to why some magical hike
in output voltage has not been observed (by anyone I know anyway) -
the secondary *does* in fact ring up at Fr and is in fact already
coherent.

Malcolm
<snip>

```