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Re: Research directions


-----Original Message-----
From: Tesla List <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: Friday, April 14, 2000 12:49 PM
Subject: Research directions


>Original Poster: FutureT-at-aol-dot-com
>
>Hello all,
>
>Although much of TC theory is now understood, probably the greatest
>mysteries still lie within the area of streamer dynamics; how the
>streamers grow as a result of various TC configurations, and why the
>sparks branch in various ways.


It on my To-Do list to get some books refered here on spark and arcs. I have
a basic understanding from things I've read about high-power switching.
Anyways one concept I'm entertaining now is that:

1. An ion channel is initiated from a pin-streamer source

2. the current into an arc can be controlled, such that arc instabilities
(kink, sausage, pancake) don't develop


3. alternating charges are applied to the path, so each discharge follows
residual opposite ion path of the previous charge

then it may be possible to produce directed, straight discharges, over a
single channel that are much hotter and brighter.

Of course this requires formidable control challenges, a constant current
regulator on the primary or secondary.

Scott



>We know that a higher break rate will tend to coalesce the sparks and
>cause spark growth due to the re-ignition of streamer ion channels.
>What is unknown is what the best break rate might be.  Some have
>said that each TC requires its own best break rate.  This may be true,
>but is not quite what I mean.  What I mean is; of all the possible TC
>designs and break rates can be be utilized, which is the absolute best
>for obtaining max spark lengths using minimum input power.  However,
>one would not want to reduce the break rate to the point where the
>sparks appear to be intermittent or pulsed because this would be
>"cheating".  Certainly one could pulse a coil once a year, and say it
>was "very efficient".  (please see below for how I'm defining efficiency
>here)
>
>Everytime I write what I'm writing here, someone responds by saying
>that their sparks got longer as they raised the break rate.  This is not
>what I'm refering to.
>
>I have done some tests at relatively low power levels that suggest that
>a break rate of around 120 bps is best.  Higher break rates may give a
>brighter or fuller spark for the same spark length, but more power was
>then needed.  As I increased the break rate, the TC became less and
>less efficient.  I am defining efficiency here from a practical standpoint
>of spark length vs input power.  I am not refering to charging efficiency,
>but solely to effects occuring once the capacitor is already charged,
>and measuring wattages based on cap joules and bps.  Gap losses,
>and other losses come into play here too.
>
>The performances of Greg leyh's two large TC's were very interesting,
>as well as awe-inspiring.  His older coil had a somewhat linear break
>rate vs spark length relationship;  If you doubled the break rate, the
>spark length would tend to double.  In contrast, his Electrum TC, was
>less dependent on break rate.  Almost full spark length was achieved
>at a relatively low break rate, and higher break rates added mostly to
>the fullness of the streamers rather than their lengths.  It had been
>suggested that a larger TC can tolerate a lower break rate.
>
>It is easiest for these kinds of comparisons, if the coils being tested can
>provide a variable break rate along with a constant bang-size (as Greg's
>TC's did).  DC coils of various types tend to fit the bill nicely here;
>systems such as Greg's rectified 3 phase system, Larry Robertson's
>H-drive, or Marco's solid state TC driver.
>
>Much may also be learned from running pulsed CW systems.
>
>Much work to be done,
>Cheers,
>John Freau
>