Re: lightning, Xrays

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>


 >          There are lots of  'industrial x-ray sources' that
 >          use radio isotopes, no power, no vacuum.  I believe
 >          X-Rays from hot plasmas (of which lighting is a case)
 >          have been described: it takes VERY high energies,
 >          and specific conditions.  I Suspect usual coiling,
 >          at least up to pole-pig levels, is too low.

I'm not so sure... lightning is fairly high energy... 100 kJ/meter is a nice
round number, and the peak power is fairly high: that 100 kJ gets dissipated
in around 10 microseconds, so 10 GW/meter power levels.  But the real
question is the mechanism by which the energetic radiation gets created..
Is it a pinch effect?
That's what does it for high di/dt discharges.. but lightning isn't anywhere
near that kind of di/dt (at least the return stroke)

Is it an efield effect?
Well, lightning strikes occur in a field around 10-20 kV/meter, a lot less
than that around a TC, which is probably more like 100 kV/meter), but maybe
there is a high field in the immediate vicinity of the stroke or leader..

While it's not directly TC related, I wonders if one were to set up a
"exploding wire" type experiment at 50-100 kJ/meter kinds of energies with
microsecond scale discharges, whether you'd be able to detect anything..

At least with lightning, your detector can get the radiation from very many
meters of discharge, which does help with the probability of detection.

Sort of the next step for you pulsed power afficionados after you've gotten
bored with shrinking quarters...  Get to fool with all sorts of other nifty
HV stuff (like PMTs).. and, better than using a wire (because, as Malcom
points out, the UF experiments had metal in the spark), you could use a
streamer from a TC as the discharge path (a bit of clever design will be
required here to make sure you don't dump that 100 kJ into your poor little
TC)  It wouldn't need to be a big coil... say you want to discharge 50 kJ
over 0.5 meter... Using the "Freau equation" a few hundred watts into the TC
should do it (a NST powered coil..)