Re: Making lightning with a thin wire

On 21 Dec 2006 19:34:30 -0800, Electroniker <Railtramp@xxxxxxx> wrote:

Winfield Hill wrote:
Ignoramus17570 wrote...

Another question, can such things be viewed with an autodarkening
welding helmet. (1/20,000th of a second darkening time)

Be careful: 50us isn't fast enough.



While in college, I worked in an on campus instrumentation lab. Our
job was to build whatever it was that researchers needed. I was given
the task of designing an safe fuse and detonator for an
acetelyne/oxygen bomb developed by the US Bureau of Mines. It was
called a CERB (Controlled Electronic Rock Blaster).

The fuse consisted of a piece of #30 wirewrap wire strung between two
mounts. This was sealed into the gas mixture housing. The fuse was
considered safe since only a huge amount of energy could cause
ignition.

Ignition was accomplished by charging a large capacitor (5 uF) to 15
KV. This cap was the input to a triggered spark gap. The output was
the #30 wire in the gas mixture chamber. The cap was charged, arming
the circuit, and then the spark gap trigger by a thyraton, causing the
cap to be discharged into essentially a short.

Pretty much what I did this evening. Same voltage even. It was
LOUD. OMG. What did you say?

The discharge event lasted less than 5 usec, in which time, the wire
would vaporize igniting the gas mixture. A combustion wave would
propagate down the cylinder, and at 100K psi, a shear plate would
release, sending a shock wave down toward the area to be "blasted".
The theory was that the shock wave could be more controlled, better
directed, and the blast would consume less energy than conventional
explosives.

That was used in some nuclear weapons also (blast directing foil onto
the secondary explosive).

This was one of the best projects I ever got to work on. The first
test was in a basement lab and we had no idea what the effect of that
kind of force would be. The room was destroyed. The shear plate
punched a hole in the concrete wall, all the lights were in shambles.
Later, a steel plate was used as the target and even this ultimately
had a hole abraded through it.

sounds like fun.

i
.