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RE: Streamer growth and filming it all

first some assumptions/definitions: 
1.) streamer&arc Fself-oscillation >> Fres Secondary so Xc_HFarc=low ohms,
    implying >>HF enhances connections over longer distances due to lower Xc
as freq ^ )
2.) streamers(disconnected) & arcs (connected to plate opposing top terminal
    which could be any significant conductor possessing sufficient effective
size
    enabling energy storage/sinking capacity to produce the connected
visible power arc)
    represent breakdown in the dielectric, air 

Here is my guess (educated from my experiments w/single shot mode, gut feel,
etc),

a.) A streamer or arc starts life as a (relative) conductor,
    a physical projection relative to its local surroundings,
   (and at microscale, exaggerated/attracted by opposing physical structure)

    the projection functioning as a very effective and sharp pointed field
concentrator 
   (ref: AFM Atomic Force Microscopy)

    above a TBD field intensity threshold, (TBD=in controlled STP still,
N2/O2 air mixture)
        one perceives the corona glow, the visible blue/uv light emission
spectra 
        resulting from concentrated local field ionic breakdown
    below this threshold, a field is present and reaching out randomly
    but directed/attracted by random dielectric reactance's of relative
opposing plate(s)
        a dynamic network of reactance's 
       (which range from dielectrics of different densities 
        to isolated conductors (plates) possessing charge/reactance, series
capacitor(s)
       (even your body as you walk around - possesses capacitance, reactance
and charge
         a dielectric breakdown streamer/arc attractant 
    participating in the complex top TC terminal capacitance)
    and finally to larger structure conductors (room walls ceilings) which 
       present the lowest reactance, the first order opposing plate to the
top terminal.

b.) Streamers stop growing visually when field intensity is not sufficient
to maintain air 
    ionization, including hysteresis 
      (initiating field intensity needs to be higher than the field to
sustain streamer)
    which is related to the Ctop potential and how much and when it deviates
as a function 
    of how many of what length streamers are continuing, growing, receding,
newly issued or
    terminated due to local (may not be global, reactance isolation?)
potential fluctuation. 
    nS propagation's produce random potential paths in the Ctop surface from
Fres impulse
    yielding random corona (or leaders which may become arcs) emission
points
    that follow the path of least resistance (reactance). 
    Corona reaches out along the path of least resistance each time,
    the path of least resistance is simply changing quickly but may retain
physical 
 (d)identity such as in the Banjo affect at moderate break rates. 
    Multiple bangs may serve to make the discharge medium more consistent
   (more uniformly excited ? ) than occurs with long interval single shots.

c.) This could be best answered using them in the instrumented Single Shot
Mode.
    On a single TC, My Oscilloscope verifies each arc event to be unique
    defying prediction as to what nature of output pulse is produced, 
    some + or - polarity only, some both, though all brief <1uS period most
<400nS
       under identical physical point to point arc external conditions 
      (then no two arcs take the exact same route/path !! 
       each arc's electrical length varies as a function of that route, 
       ref: Tesla's 'straightening out' of his arcs)
    nor correlated to when, in the resonant rise the arc occurs.

    Bottom line, there are abundant potential differences opportunities 
    between two coils to put on a good show.
    It would be a great show to demonstrate like polarity repulsion,
    if you could devise the controls in polarity and time.

----------------- other
x.)  I use an Olympus DL-100 2.2Mpixel digital camera for arc capture & a
Panasonic VHS-c.
     Both use CCD's, I've experienced no serious problems. 
(some noise when video of Jeff Parisses 5-6' Tesla demo at Moorepark
exhibition,
 none from Overstreets ~4' nor at SoCal Teslathon)

The problem with CCD still capture is there is no Open Aperture capability, 
(no B bulb option probably concern for accumulated dark current wash out)
making timing exposure tricky.

I need to press the DL-300 button ~1.5 sec before I trigger my single shot
TC !

But I do have a host of nice pictures as a result, already in .jpg format to
post process.

I would like control of the exposure duration. 
By random chance 
I capture some just the end of arc (late press) or 
just the beginning of an arc (way early press)
the difference is obvious from the lack of saturation in the arc channel 
i.e. its all a pretty blue rather than white ! 
or one end is blue the other white.

I don't think I've ever captured the mid-white affect as is frequently
visually seen.
May shed value on difference in the 'capture' of CCD vs our vision ?

It does poorly on disconnected Streamers from a photographic/artistic
standpoint
but I can post process and enhance all the branches losing color and
background quality.

Regards, Dale 
Redondo Beach, Calif

-----Original Message-----
Sent: Wednesday, November 03, 1999 10:58 AM
Subject: Re: Streamer growth and filming it all

Original Poster: "Reinhard Walter Buchner" <rw.buchner-at-verbund-dot-net> 

Hi Jeff, Jim, Terry, John, all,

A few comments in general first.  What I would like to
see is how exactly streamers (and/or arcs) are formed.
A few questions that pop up right away are:

a.) How exactly do they form. Do they form nm for nm or
     does the initial streamer "lash out" a few inches and grow
     the rest of the length?

b.) Why do they stop growing. Is it really *just* a matter of
     temperature. In other words, does the ion channel simply
     cool off too fast?

c.) Using two coils, how are streamers attracted to each other?
     The point where these two connect must get pretty hot. Why
     donīt (or do they?) branch out from here?

d.) What is it with the Banjo effect? Is it really just a matter of
     the surrounding, heated air, which drives the sparks into
     this form. If so, why do they go up and down (i.e. the banjo
     form). I would expect, sooner or later the air is hot enough
     to just move the streamers upward, similar to a Jacobīs
     Ladder, until the rip off.

e.) How (if it) does the ion channel change, once the streamer
     hits something grounded (i.e. turns into an arc)? I think an
     infrared film would help as one could analyze the spark
     and ion channel temperature.

f. ) Following d & e: I would think the banjo effect would be more
     pronounced once an arc forms (more current=> higher flame
     temperature), yet my coil seems to form more "banjos" when
     it is simply "streaming" into thin air.

g.) Why and how do streamers branch out. Is it really the same
     streamer or is it just an optical illusion, (i.e. not really the
     same streamer), because our eyes arenīt fast enough to
     detect this.

h.) High speed filming of the RSG, might also tell us something.

>As you can imagine synchronizing with the spark
>development might be a challenge.

Do you really mean *synchronizing* the two or do you
mean *starting* the camera at the right moment. Clearly
you will need to start the camera just a "nanosecond"
before you start the TC,  but why would you need to
*phase* camera and spark?

One reason AGAINST the electronic camera: Itīs
electronic ;o). You would have to be sure that it is
within a well shielded enclosure to prevent EMF, AM/FM
noise from false triggering the camera and "knocking
out" the CCD. Also, you would need to protect it from
getting hit from any sparks. 

Coiler greets from Germany,
Reinhard