Re: [TCML] Lichtenberg on TV

[Carl Noggle <cn@xxxxx>]

The Lichtenberg figure forms often when sparks slide over the surface of 
a dielectric.  It is typical of dendritic figures that form when water 
or some substance has to spread out (or be collected from) a surface (or 
in the case of Bert Hickman's figures, or tree roots).  In this case, 
charge has to be distributed.  If the dI/dt is fast enough, the high 
dielectric constant of the water in the body will dominate over the 
resistivity and the current will flow over the surface.  dI/dt can be as 
high as 10E11 amps per second in the vicinity of a lightning strike.  
This is probably why only about of 10% of lightning strike victims die.  
Power line electrocutions, however, are very often fatal, since the 
dI/dt is much slower and the current can flow into the body.  This is 
basically a skin depth argument in the time domain and applied to a very 
lossy dielectric.  We would not expect figures on the skin of a power 
line electrocution victim.





> On 1/7/12 4:08 PM, Bob Wroblewski wrote:
> > On the CBS network television show A Gifted Man (Friday night 
> > 1/6/2012) the storyline featured a young boy with a perforated 
> > eardrum. Upon removing his shirt to check for other injuries there 
> > was a prominent Lichtenberg pattern on his back. I immediately said 
> > to my wife he was hit by lightning. The doctors on the show were 
> > puzzled and searched online to reach the same conclusion soon after.
> >
> > My astonished wife said how did you know that before the doctors? So 
> > I related a story of several Rochester Teslathons where Bert Hickman 
> > made and sold Lichtenberg figures in various acrylic forms and I have 
> > several on display in my office cubicle. They are also viewable at 
> > his Teslamania.com website.
> >
> > Anyway the episode should be available at the cable tv on-demand or 
> > network websites or hulu or elsewhere on the interweb by now.
>
> I had a similar experience at a family gathering where one of the guys 
> was an ER physician, and he had some journal with a "what causes 
> this?" mystery puzzle in the back. It was the photo of a man's back 
> with a great Lichtenberg figure on it, prompting speculations about 
> some sort of weird dermatitis, or a surface skin infection that had 
> spread.
>
> I saw and instantly said, Lichtenberg figure, he was hit by lightning.
> That's what it was, of course.
>
> Here's a TC list question about which I've been wondering... Would 
> such a figure occur with an ordinary HV incident (e.g. contact with a 
> power line).  Or would it have to be pulsed power with very high peak 
> current/voltage?
>
> Lichtenberg figures are similar to the dendritic treeing that occurs 
> in dielectric, but not from the same cause, as far as I know (and 
> treeing is a long duration aging kind of effect), although the fractal 
> nature IS similar (and for the same reason.. field distributions)
>
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