Re: How do I make a #12 Nickel wire explode

OK, Spencer, let me first say that you are a crazy man. :-) Although I have
no direct experience with exploding-wire plasma experiments, I do know that
they involve advanced pulsed-power systems that I would be wary of building
without a great deal of help from high-voltage experts. The only recent
journal articles I could find regarding such experiments were Japanese or
Russian. I did find a few old references by a guy named E.C. Cassidy at the
National Insitute of Standards and Technology, back in 1968. You can find
them at http://www.eeel.nist.gov/811/div/811_pubs_hv.html.
Only the references are there, you'll have to hit a library for the actual
articles. I couldn't find anything on the Web about current exploding-wire
experiments.

As any good physicist would do who knows little or nothing on a particular
subject, I did a few rough calculations. I won't bore you with the details, but
in brief you need 7.6 electron-Volts of energy to ionize a single Nickel atom.
That means you strip the outer electron off the atom, resulting in a plasma. If
you want the plasma as hot as the sun, you need an extra electron-Volt per atom. 
One centimeter of #12 wire would have about 3x10^21 atoms in it. This works out to about
3700 Joules (1J = 1 Watt-second) for ionization, assuming perfect energy 
transmission, and equal spread among the atoms. To the extent that these 
estimates are wrong, my guess could be very low. 

Based on this estimate, you need to get your hands on a 100 micro-Farad 
capacitor (BIG!),charge it up to at least 6 kilovolts, then 
discharge it through the wire. You'll need some pretty fancy switching, 
probably a spark gap, to handle the huge current discharge. You may also 
need to set up the wire in a vacuum system, to avoid discharging to ground 
through the air rather than through your wire. I think you gain alot by 
using much, much thinner wire, so the resistance will be higher and you can
use lower current. You still need the same amount of stored energy, and you 
still have to deliver it fast enough that the Nickel won't melt before it 
gets hot enough to ionize.

If you are still interested in crazy amateur experiments like this, you
should check out Bill Beatty's Amateur Scientist Web page. He has a whole
page of high-voltage capacitor-discharge "toys." He also has an excellent
disclaimer at the top about how insanely dangerous such projects are. Beatty
also moderates a few email list groups that discuss amateur science projects.
Info about them is also listed on his page.

I hate to be discouraging to a budding amateur scientist, Spencer, but you
are talking about a high-voltage, high-current experiment that is only done
in a very few specialized labs in the world. Playing with that in your
spare time is a great way to get killed.

My PhD advisor might say diffently, but your life really is more important
than the experiment! :-)

Have fun,

Jay H. Hartley
hartley1@llnl.gov