Let's outshine the sun

[Polverone]

I've been peripherally aware for a while that the shockwave from high explosives can heat noble gases to very high temperatures to produce a brief, intense pulse of light. Only tonight did I start to search for further information. For such an interesting phenomenon, there appears to be little information available online.

I extracted the following from a Usenet post that's a few years old. The original source for the text was a PDF at lanl.gov that is no longer online.

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica">... The smaller the specific heat, the greater the temperature that can be reached for a given energy input. Xenon is the best gas for reaching high temperatures, krypton is next best, and argon is appreciably poorer. On the other hand, krypton and xenon are expensive, whereas argon, present to about 1% in air, is inexpensive. Most experiments to date have been done with argon.

In argon, the temperature at the shock wave driven by a good solid high explosive is above 25,000 kelvins (K), and in xenon above 36,000 K.

... The shocked gas emits light nearly as a perfect radiator: the pressure and density are so high that the usual atomic line structure is broadened such that the lines merge and the spectrum is continuous. An argon shock wave is about 60 times brighter than the Sun, and a xenon shock wave about 100 times brighter.</font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">I have searched the web and Usenet with Google and found little more relevant information. Blinding weapons based on this principle are called "optical isotropic radiators" in a number of places. Other people mention that det cord wrapped around a balloon of argon gas will exhibit this phenomenon, though they did not mention how intense the phenomenon was. I've seen references in a few places to using multiple shock waves to achieve high compression/radiation of the gas.

I was unable to find further information in the databases I have access to, but my school doesn't subscribe to a lot of engineering/physics information. I've also run a few searches on the US patent database and didn't come up with anything relevant.

I see a few possibilities here. The first is that inducing mega light pulses in noble gases is so simple that nobody writes about it; you just detonate your brisant high explosive of choice in the chosen gas and BOOM - instant light. The second is that work in this area is obscure and/or militarily significant so not a lot of details about techniques are available. The third is that there simply hasn't been much experimentation in this area.

It's definitely an area that interests me in the abstract. Were I to obtain a cylinder of argon (an expensive proposition due to cylinder costs) I would certainly be interested in experimenting. A cylindrical charge of PETN down the center of a polyethylene soda bottle filled with argon? Look away from the explosion, of course...

I'd also be interested in proposals for merging shockwaves to maximize the light output of the gas. Does anybody have further references?

[nbk2000]

I believe that reason 2 (obscure AND militarily significant) is the reason why you can't find any info.

The isotropic radiator is being developed as a NLW to "temporarily" blind enemy troops. I put the word in quotes because it's not likely to be that if you're close enough to it.

I believe it starts out with the gas already highly compressed, and then it's shocked with explosive to excite it enough to give off light. I'd imagine some type of implosion, similiar to a muke design, is used to achieve the compression since I can't imagine a "stick in tube" design providing enough compression. Unless, of course, it really is so simple that just wrapping detcord around a ballon would do it.

If so, then small vials filled with xenon gas or such could be added into explosive devices to add a nice flash effect.

The closest I could find to relevant info was here:

<a href="http://www.google.com/search?q=light+emit+xenon+compression&hl=en&lr=&ie=ISO-8859-1" target="_blank">http://www.google.com/search?q=light+emit+xenon+compression&hl=en&lr=&ie=ISO-8859-1</a>

This mostly brings up soniluminescence (sound to light), but (with some imagination) could be applied to explosives.

<small>[ August 09, 2002, 05:12 AM: Message edited by: nbk2000 ]</small>

[Mr Cool]

I've seen a patent - I think it might be in the appropriate section here - that uses a HE-induced argon flash to pump a dye/ruby laser, for use as a blinding weapon. IIRC they used 3g of PBX (&gt;= 5kJ/g) and argon at 1atm, but I'd need to check to be sure.
I'm not sure if it'd work with an implosion design. Sure, you'd get a lot of light, but would the detonation products and regions of different density interfere with it too much?
I'm thinking of a shaped-charge like device, but with no liner, or a hemispherical cavity in a charge. The cavity is filled with argon at the required pressure, and when detonated it is compressed from everywhere except the front. The gas is heated to incandescence, and the light has a clear path away from the detonation.

[PrimoPyro]

Couldn't the same thing be accomplished by pumping the same amount of energy in the form of electric discharge into the gas, like a laser exploits for example?

The principle, I think anyways, is derived from the atoms becoming so raidantly energetic that the electrons jump to higher states to absorb the energy. As collisions occur between gas atoms, these electrons cascade back down to their ground states, falling through the orbitals, and releasing photonic energy energy that is a direct function of frequency is related to the energy drop from orbital to orbital. Since the electrons of various atoms are likely to be in several different energy states, you get several (probably thousands) photon frequencies, which is of course percieved as white light. The extreme intensity would come from more gas being subjected to this, or "further subjection" of the gas to the effect.

What I mean is you could either

a)use a bigger explosive and more gas (i.e. a bigger device) to get a bigger/brighter effect, or

b)Have a more efficient design, allowing more absorption of thermal and kinetic energy in the same amount of time before collisions react to transform the energy into photons. Personally, I dont think b actually works this way, I think the effect of this would be higher energy photons, not more of them.

The easiest way to get more light is to use more gas, and just compress it.

So I wonder, if a huge leyden jar-like capacitor of a few hundred farads, maybe a kilofarad or two, could accomplish the same effect? Like those lightning balls again heh. The center electrode would be the hot wire, and the spherical orb around it would be the ground electrode. The space between would be filled with compressed noble gas. Zap! Boom!

PrimoPyro

[PYRO500]

A few hundred farads! At high voltage! In a leyden jar! I don't think so, for a leyden jar to store a farad at just say 10KV you'd have a jar the size of a small town! They aren't really designed for peak power storage or anything that stores massive amounts of energy.
Even pulse capacitors (with decent ESR and hookups) would have to be the size of many rooms to do that. And after all that you'd need a few hydrogen thyristors triggered by IR lasers to control that electricity.
I think a better use it to use the extreme energy to pump a masive "super laser" although COIL lasers are looking more and more practical these days.

The problem I see with the nobel gas plasma giving off light is that it uis not going to be coherent or monochromatic (most likely) instead you have something like a xenon discharge into the air witch wastes a whole lot or radiation across the spectrum some wavelengths will penetrate the air beter and some will be stopped by it. with a massive explosive driven flashlamp driving a very large Nd:YAG or even better synthetic ruby laser tube you could create a very powerful discharge that's likely to very rapidly things on contact with the beam at fairly far ranges if you can keep the beam coherent.

[Mr Cool]

PrimoPyro: "Couldn't the same thing be accomplished by pumping the same amount of energy in the form of electric discharge into the gas, like a laser exploits for example?" - of course it could, haven't you ever seen a camera flash?!

COIL - chemical oxygen/iodine laser, right? I never understood how they got these to work. It is my understanding that it reacts atomic oxygen with iodine vapour to cause the population inversion required for lasing. BUT, how do they keep the atomic oxygen atomic?! I've seen a demo (in fact, the same demo is shown on a site which I think I got to from a link here somewhere...) where chlorine is passed through 30% H2O2 to produce atomic oxygen, which very soon recombines and causes a deep red chemiluminescence. I don't know how they stop it from doing this for long enough to get it into the lasing cavity?

If using a HE argon flash to pump a laser, I think a dye laser emitting in the [rough guess] green [/rough guess] area would probably have absorbtion characteristics best suited to a radiator at 35K*K. A lot of light will be given off in UV-&gt;blue, but Nd:YAG is best pumped by red/near IR, and ruby by green wavelengths I think.

[Polverone]

You know, the reason I like this idea is because it *is* so uncomplicated. Pumping a laser rod with the flash may be a good idea, but am I going to recover the rod afterward? I might, if the charge were small enough, but then what's the point of using explosive pumping? It's not as if I need a system that's battlefield-ready. Shocking some argon seems to be straightforward and inexpensive enough that it might actually be done by a forumite, instead of just speculated about.

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica">I'm thinking of a shaped-charge like device, but with no liner, or a hemispherical cavity in a charge. The cavity is filled with argon at the required pressure, and when detonated it is compressed from everywhere except the front. The gas is heated to incandescence, and the light has a clear path away from the detonation.</font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">I rather like that idea. But I just realized something that had been nagging at me. The mysterious disappeared PDF that I quoted said that with argon you could achieve 60x the sun's brightness, and with xenon 100x (I wonder what radon would give you :D .) But they don't state at what distance from the explosion this brightness is measured! The sun is so distant that the relatively small movements possible on the earth's surface don't really matter, as far as changing brightness; the sun isn't appreciably brighter at 2000 meters than at sea level. But for nearer light sources, the inverse square law really matters.

[PYRO500]

You know, on my little internet quest to find more information on he net I happened to find a pdf not only mentioning the name of the device you mentioned but a whole taxonomic table of all the classifications of future weapons for the military. this is the first file I have actually come across that mentions the curdler unit and other things included in nbk's first pdf. I think this table is one to save. <a href="http://www.dtic.mil/ndia/nld4/fenton.pdf" target="_blank">http://www.dtic.mil/ndia/nld4/fenton.pdf</a>

[xoo1246]

I posted a patent number a while ago discussing an explosively pumped laser, well, here it is again.
#5,052,011

[Energy84]

Aren't computer monitors/tv's picture tubes full of argon? I can't remember and am too damn lazy to check, but if that's the case, couldn't you just make a BIG charge of ANFO or something (ANFO would be the cheapest bulk explosive I believe), enough to completely surround the monitor or tv and just detonate that?

[nbk2000]

The topic isn't lasers, rather explosively pumped flashbulbs (for want of a simplier analogy).

If the gas was contained in an optically resonant cavity (ala laser) that might be the difference between a flash and a gas. <img border="0" title="" alt="[Wink]" src="wink.gif" />

It still seems to me that implosion would be the key to compressing and heating the gas to an incandescent state.

[kingspaz]

it all depends how much light would be absorbed by the explosion....when i think about it its unlikely not much will be. it would be insignificant i think.

also i think so long as the explosive isn't very smokey then it should work fine. TNT and other very oxygen deficient explosives would produce alot of smoke absorbing a fair bit of light.

<small>[ August 09, 2002, 06:40 PM: Message edited by: kingspaz ]</small>

[xoo1246]

Ok, you don't want lasers, then this is an interesting patent, to kill/confuse the optical system of missiles. Basicly a ballon that inflates with noble gases, then a charge detonates inside the ballon.
Creating a nice little flash.
#6,324,955 (Explosive countermeasure device)
Here is an images taken from the patent on the inflated ballon before it detonates(I added some descriptions). For those who can't view full page patents.
<a href="http://w1.478.telia.com/~u47802930/Flash.jpg" target="_blank">http://w1.478.telia.com/~u47802930/Flash.jpg</a>
Don't know what pressure the ballon had before it detonated.

Edit: Try filling a condom(transparant) with aragon, but before you fill it, add a detonator(electrical) containg an apropriate amount of primary. Detonate(don't look at it).
Or better use a container such as a plastic bottle that can withstand a little higher pressure(fitted with valve, makes it a bit more complex ).
It might be as simple as it seems(ofcourse you get lower light-output), why not try it?

<small>[ August 10, 2002, 07:44 AM: Message edited by: xoo1246 ]</small>

[Anthony]

You can buy 1kg dispossable argon bottles for little MIG welders, few quid a pop and pressurised to over 100bar IIRC.

I wonder if it would work to just stand one upright in a bucket of ANFO, probably with the top uncovered if the gas needs a "way out"?

[xoo1246]

It could work and there is only one way to test it. <img border="0" title="" alt="[Wink]" src="wink.gif" />
I'm working on a pressurised(with argon an a little CO2) plastic bottle. Maybe I'll try it with a detcap.

[nbk2000]

I wonder if a Xenon Halide compound would be more effective than the plain gas?

[Mr Cool]

Too expensive for a start! And you'll have the bulky halogen taking energy away from the xenon. Hmm.. although this wouldn't be too significant if you used the flouride, which is probably the easiest to form anyway. What's the AM of xenon, 60ish? Fuck knows. Anyway, I think it'd be too expensive.
But hey, if you're using a compound get HE and noble gas in one and go for xenon trioxide!
Anthony: do they have those in B&Q (for example), or only specialist welding shops? Not only could I use the argon for this and other stuff, if they're cheap then I could get one and use the case for stuff too, e.g. cannons, crucibles (I'm tired of porcelain, I always crack it :(, plus these could be made to have a narrow opening, to keep air out, as is required for making CaC2, CaNCN, NaCN etc) and whatever else I think of. Perhaps I'll go and have a look...
Another thing to think about: do you think it might help if you mixed in a bit of C2H2/O2 mixture into the noble gas, to give it an extra boost? Or would this soak up too much energy from the shock wave of the HE?

[kingspaz]

i think the addition of C2H2 and O2 would help considerably. when C2H2 burns its very bright and hot so, when mixed with the noble gas being used it would be in direct contact so transfer energy better. not proper direct contact like in solids but if an implosion device was used the lot would be crushed to a very high temperature, denisity (better energy transfer) and pressure.

[xoo1246]

I read in a patent that explosives that produce alot of water reduce the light output.

[nbk2000]

Perhaps an explosive gas like Hydrazoic acid instead? This explodes at higher velocity than methane possibly could.

Assuming you actually can get a decent isotropic radiation effect, what would you use it for?

I'm thinking one good use would be to flash blind/destroy NVDs, such as sniper scopes or googles. The newest generation have ABC (Automatic Balance Control) that allow them to run even in daylight, but I don't think they'd react fast enough to protect the tube from an Iso flash since this is in the microsecond range, and much greater intensity than the sun (apparently).

Perhaps a specific ratio of an inert gas (Xe/Ar/whatever) with another gas/chemical could shift the flash from full spectrum to primarily IR. This way it won't affect unaided night vision (your eyes), but destroy your enemies NVD advantage. That, and it'd greatly conceal the source of the damage since their equipment would burn out in an instant, but they'd only hear a Boom!, but see nothing. :D

Then, once they're relying on eyes, you flashblind them with a fully visible Iso bomb to blind them while you cover your eyes. Now they're totally blinded while you can now use YOUR NVD with impunity. <img src="http://www.roguesci.org/ubb/icons/icon23.gif" alt=" - " />

Even more hi-tech would be to couple the Iso to an electro-optic LCD shutter that'd engage for only a second while the Iso is flashing the enemy (full spectrum), disrupting all their vision/optics, while protecting your eyes/NVD. The shutter is coupled to the RC det that controls the Iso's.

Speaking of radiation, a 1% solution of Triethyl aluminum (TEA) in n-Hexane, when dispersed and ignited in air by an explosion, burns with such intense heat that it causes 3rd degree burns from infrared heating, with no direct contact with the deflagerating TEA. Nukes are the only other weapons capable of that. It also burns with a blinding white light, similar to a magnesium flare, that'd burn out, or at least shut down, any NVDs in the immediate area.

<small>[ August 11, 2002, 09:35 AM: Message edited by: nbk2000 ]</small>

[Anthony]

I'm 99% sure I've seen them in B&Q, the range consists of pure CO2, CO2+argon and pure argon, if B&Q don't stock one of these it's probably the pure argon. Machine Mart definitely do them. Not sure about the price though, especially in B&Q (it's a distant memory :) ).

One thing that occurs to me is, I presume that a device like this would be tested at night? If so, how can we be sure it has worked (to a degree) considering that the explosive itself will produce a bright flash?

[nbk2000]

Photography light meters. :)

Or, you can make a simple meter from a photovoltaic cell from Rat-Shack and use that.

Then, simply explode two similar devices, one with, and one without, the gas filling. Compare the light output.

However, because of the extremely short duration, you may have to use filmstrips covered with variable density tint to determine which one is brighter. <img border="0" title="" alt="[Frown]" src="frown.gif" />

[xoo1246]

I'm planning to detonate a 2 gram HMTD B.C. in a 1.5 liter plastic bottle pressurised(I can't tell what the pressure is) with gas used in welding (argon/CO2) to see if there is any noticable effect at all. Hopefully I will get around to assemble it soon. The bottle is ready and I have the cap filled, need to assemble the ignition device.
I have tested to discharge 300 volts through a iron filament(explodes) in the bottle filled with gas to see if there was any difference in light output between that and in air. But no.
What do you think?
Edit: Here is an image of the bottle with bike-wheel valve. <img border="0" title="" alt="[Wink]" src="wink.gif" />
<a href="http://w1.478.telia.com/~u47802930/Bottle01.jpg" target="_blank">http://w1.478.telia.com/~u47802930/Bottle01.jpg</a>

<small>[ August 12, 2002, 02:29 PM: Message edited by: xoo1246 ]</small>

[nbk2000]

Filter out the CO2 first by passing the gas through lye water.

[nbk2000]

Here's a picture I found in a LANL PDF about criticality experiments.

<img src="http://server3001.freeyellow.com/nbk2000/xenon2.jpg" alt=" - " />

The xenon gas in the plexiglass chamber is going from 1 Atm (~15psi), to 140kbar (I don't know what that is in Atm, but I'm sure it's a lot) in 10 microseconds under magnetic flux collapse. This causes the xenon to do its thing (flash) as the shockwave (adibatic compression) travels through it.

<small>[ October 19, 2002, 02:58 AM: Message edited by: nbk2000 ]</small>

[xoo1246]

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<small>[ December 11, 2002, 01:02 PM: Message edited by: xoo1246 ]</small>

[nbk2000]

How hard is it to pass a gas through water? :confused:

ANywyas, the thermite mix you mentioned ISN'T suitable since it's the compression of the gas that causes the effect. And, in order to compress to sufficient pressure for it to flash, you need a very fast and brisant explosive. ANFO wouldn't (likely) do it, so certainly not something that's not much faster than gunpowder.

Though it might be useful as an anti-electronics explosive. (?)

[zaibatsu]

140Kbar = ~138200ATM or over 2,000,000 PSI! <img border="0" title="" alt="[Eek!]" src="eek.gif" />

[xoo1246]

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<small>[ December 11, 2002, 01:02 PM: Message edited by: xoo1246 ]</small>

[Mr Cool]

There is NO WAY that an Al/CuO mixture could raise the gas to 20,000+*K!! It would probably burn at only 1/10th of that temperature, and since it isn't a brisant explosive the shockwave won't manage it.

This is something I have wanted to do for a while, but have never done so because I was unaware of the availability of argon at B&Q! If the price is right I might pick up a cylinder next time I'm there, but I won't be able to try a big device, and I won't be able to show you anything except before and after pics <img border="0" title="" alt="[Frown]" src="frown.gif" />

[xoo1246]

Remove

<small>[ December 11, 2002, 01:02 PM: Message edited by: xoo1246 ]</small>

[nbk2000]

I think you're risking failure by allowing the CO2 to remain mixed in with your argon.

[xoo1246]

You think so? It's very possible, but I will give it a try, and in the next test I could use somewhat pure argon.

[Mr Cool]

xoo1246: The first post indicates that these things work at 25,000*K with argon.

I think the best explosive would be pure, high density RDX or PETN. No Al or other additives as these lower brisance.

[xoo1246]

Ok, my fault.
The conclusions are, use pure noble gases at high pressure, chock it with a explosive that has a high brisance to get the maximum intensity? So this has actually little to with temperature of explosion then, since it's not hight enough but the compression that the shockwave performs on the gas generates the high temperature.
Stupid me...

But the question remains, could an explosive with much lower vod be used to produce an useable(what is that?) flash?

NBK, what I meant with that CuO/Al explosive used as an anti-electronics device was that possibly the copper particles would allow current to go from say the power lines to the ground.

[Mr Cool]

I think most HE's would produce some light output, although with ANFO etc it might be an insignificant amount. You could probably get away with ANNM, but this is all just speculation. Just use the HE with the highest VoD that you can.
Hopefully I'll be going to check the prices of argon cylinders tonight, so I might be able to do some small tests soon. Do you think a 250mL pop bottle could be pressurised by turning the argon cylinder upside down, and squirting in a small amount of liquid argon and then sealing it? It'd be purged of air first, so that it only contains argon, but do you think the cold would weaken the bottle and make it crack or anything? This is one thing I'll try.
Camera flash tubes only use about 5J of energy in the flash cap, even if the HE method was 1/100th of their efficiency you could get a similar light output with about 0.1g of HE! What do you think, is that a reasonable conservative estimate of efficiency?

Also, I may be able to video my tests by borrowing a friend's camera, do you think it would damage the electronics in anyway, assuming the flash was a few times brighter than a camera's? I'm just worried about the very short duration = very high peak power...

[Arkangel]

For stills, how about a camera that you can hold the aperture open, sat behind the glass from a welders mask? That way you it's not going to pick up any ambient light, and as long as it's never pointed at the sun, you'll just get the image of the flash/explosion.

(Really interesting thread though Polverone, thanks for starting it)

<small>[ August 14, 2002, 10:40 AM: Message edited by: Arkangel ]</small>

[Mr Cool]

That should work, but I don't have a suitable camera :(
If I can't get any video footage I'll draw an artist's impression of it in MS Paint :)

[Anthony]

Maybe point the camera at some nearby trees or other screen for the first shot? So that the camera sees the lighting effect of the flash rather than the flash directly.

The critical temperature for argon is -122*C, so I doubt that it's going to be liquified in the bottle :)

[Eliteforum]

Maybe of pointless information, but argon has is pumped in between double glazed windows.

[xoo1246]

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<small>[ December 11, 2002, 01:04 PM: Message edited by: xoo1246 ]</small>

[pyromaniac_guy]

i dont think you have to worry about the pressure of the gas being shocked, for example, flashlamps used for pumping lasers would have a pressure measued in a few torr, and small volumes.. the active volume of a 25 kj rated flashlamp is &lt;100 ml.... a 2l pop bottle should be much more than sufficent, even at STP [if you have never seen a 25 kj strobe go off, it is awsomely bright... standing in a 2000 sq ft or so room, with my back the the flashlamp [eyes open] still gave me an afterimage akin to staring at the sun for a long period of time.]

i would say use only a noble gas, up the explosive content, and use whatever has the fastest Vdet you can get your hands on...

Also, for those who suggested to use this phenomina to pump a solid state laser, most mediums such as nd yag or yag, and ruby have a top end energy storage of a few j per ml of volume. if you use a generous 5kj per liter as energy storage density, you can extract assuming 100% efficeny 5kj of laser pulse for every liter of medium you have... since not even the best system can extract all of the sotred energy, lets say maybe 2.5kj per liter... now the fun part. a laser rod a liter in volume would probably cost on the order of a new nissan maxima if the host was the least expensive nd:glass you could find. if it was YAG or ruby, you would have your choice of buying the rod or a new lamborghini... and since you are explosivly pumping the gaim medium, it's an awfull expensive one shot laser!!! FYI it takes about 60j of energy from a burst mode laser to vaporize a cubic millimeter of steel... 2.5 kj isnt going to do a whole heck of alot of damage!

<small>[ August 14, 2002, 10:24 PM: Message edited by: pyromaniac_guy ]</small>

[Polverone]

I am not very surprised that the mix with 23% CO2 failed. CO2 decomposition is strongly endothermic, and CO decomposition even more so; I would expect that both are going to happen in the target temperature range. The whole point of using the noble gases is that they don't dissipate energy by breaking molecular bonds; they have no molecular bonds to break. Nevertheless, I salute this first experimental attempt.

As far as the CuO/Al thermite that was mentioned upthread... After reading that message in alt.engr.explosives that was quoted, I had to try the mixture for myself. I made two charges of CuO/Al in stoichiometric proportions with very fine ceramics CuO and 300 mesh Al. The first was ignited at night; it burned in a fraction of a second with a hearty "whump!" and sent glowing slag (from the igniter charge) about 10 meters into the air. The second charge was initiated in the daytime with HMTD. It gave a respectable (not huge) explosion and a thick cloud of brown smoke, which I'm guessing was colored from copper vapor. I imagine this wouldn't be very healthy for electrical equipment, especially high-voltage electrical equipment.

[xoo1246]

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<small>[ December 11, 2002, 01:17 PM: Message edited by: xoo1246 ]</small>

[nbk2000]

Told you so. :p

Just some ideas for next time:

Cover half of the bottle with aluminum foil, with the shiny side facing inwards, to act as a reflector to direct most of the flash towards wherever you're watching it from. This will increase the probability of your detecting a flash, and may even amplify the effect by redirecting the UV/IR back into the reaction ala' laser.

Use a stronger plastic bottle to increase the pressure before rupture. The more compressed the gas is before being shocked, the more dense it is, and the greater the compression from the shock.

Those 5 gallon water cooler jugs come to mind. Or the smaller ones if you're conserving the gas.

An HE core that runs the WHOLE length of the container, and is initiated from the center (as per the patent) and NOT from the end. This way all the explosive is consumed in half the time as end initiation and thereby doubles the shock impulse. :)

[xoo1246]

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<small>[ December 11, 2002, 01:19 PM: Message edited by: xoo1246 ]</small>

[Polverone]

You could theoretically use the intense light pulse to set off other explosives with a high degree of synchronization. I have a PDF around here somewhere about explosives that can be initiated with light. Some of them are actually fairly normal primary explosives, IIRC. Now I'm not sure exactly why you would need to set off multiple charges with precision synchronization but I'm sure people can come up with some good reasons.

Oh, and even though it's off-topic, I'll answer your query: the CuO that I obtained was already a very fine powder. It may have already been through a ball mill, since that's how many ceramics materials are ground. The night time charge was about 30 g and the day time charge was about 50 g. 3 g of Al/S igniter mixture set off the first charge, 2 g of HMTD set off the second.

[rjche]

The balloon patent stated an explosive inside a balloon filled with certain rare gasses would work.

The pressure inside a balloon is just a tad greater than atmospheric pressure at its location. Upstairs that pressure may be quite low.

Also the pressure generated by a high explosive is in the millions of psi at the explosive surface. that pressure decreases as the volume increases. Pressure drops as radius cubed. IF the explosive is 1 inch diameter, then at a distance of 1 inch from the surface, pressure is down to an eighth of what it started out to be.

Thus whatever is near it is going to be raised to high pressure, and that pressure will drop but still be quite high at a distance of 1 foot.

(a 12 gage empty shotgun shell full of 75% dynamite broke concrete building blocks a foot from it in air). It would set off other dynamite within about 6 inches (air) of it, or several feet of water or wet dirt. Ditching dynamite (90%) would propagate hole to hole about 6 ft apart in wet soil. Only has to prime the end hole. The others followed
down the ditch line to the end. See any blaster's handbook.

A gas would achieve hundreds thousands of psi in a balloon a foot in diameter, with say ten grams of AP held in its center on a stick through its neck, and that stick used to seal the neck after gas was used to blow the balloon to size.

the wires to fire the ap could come out the stick (or pvc tubing).

To tell how bright it got, fire it behind a barrier at night and see how brightly it lights up distant hills etc.

Also take a photo of distant hills, with time exposure opened just before firing and closed after. Do two, one with explosion and one without, to check for residual time exposure contrast from night lighting. Then compare the photo of distant hills with a sunlight shot.

If it makes sunlight type illumination at a hundred yards
the light was 4 suns at 50 yards, and 16 suns at 25 yards.

for a night adapted eye that will cause prolonged night blindness.

Course a million CP hand held spotlight in the eyes of a nighttime intruder will do a good job also.

Would be good for lighting up door busters who like to use bright flashlights to defeat any NV goggles in use. Don't use NV, use a much bigger light than they got.

Ordinary photographic flash powder is also great. That's all a flash bang grenade is.

The amount of eye desensitizing is related to the total power not so much its peak intensity. It's a chemical bleaching problem, depends on total energy absorbed.

Thus a million CP for a second could do more than a hundred thousand CP (non directional burst) that lasts only microseconds.

To see what even a hundred CP can do, with night adapted eyes, flick on the dark room's flourescent lights for 5 seconds then off, and see if you can see anything in the room that you could see before you did that.

Time how long it takes to regain your adaption.

Another factor screwing you up will be the eyes will retain the image of what they were looking at during the bright flash, after they are back in the dark again. That takes several seconds to dissipate. Helps speed it up by moving your eyeballs back and forth. Its a chemical problem, and movement hastens flushing out the bleached chemicals.

One can open adapted eyes in a dark room, and fire a photoflash or one of the older flash bulbs, and after its dark again see the room all lit up from the stored image, by holding the eyes from moving. Most can look at the image for about half a minute, and see details he didn't see while the flash lasted. Move the eyeballs and it goes away, but comes back several times, each time a bit dimmer.

Of all the methods, I believe flash powder would be the most practical, if you only wanted temporary incapacitation.

The power of a laser is because it can put several milliwatts into the pupil of the eye if it can hit that small target.

To do that with a non focused light source takes mucho power. You can calculate it. Total power of the light, spread over the size of its spot gives so many watts per square millimeter of area at whatever distance you measure the spot size.

The night eye pupil is 7 mm diameter. Area is about 150 sq mm.

If a spotlight at 25 yards is a meter diameter

That's about 3 million square mm area.

The power of the light is say 12 volts at 5 amps or 60 watts.

Efficiency is about 10 % so the light output is about 6 watts.

6 watts spread ovewr 3 million sq mm gives 1.2 E-5 watts per sq mm

or 12 microwatts per sq.

Bright noonday sunlight (no smog) puts 1 mw per sq mm. on the earth surface. That's 1000 microwatts per sq mm.

Looking directly at that causes permanent eye damage, and serious temporary blindness, especially if you go into a dark area right after doing that.

So, the lamp example above is about a tenth as serious as looking at the sun.

one only looks at the sun for about a tenth second before the eyes automatically shut.

So a 1 second look at the spotlight could cause the same degree of blindness as a look at the sun.

It would not however boil a spot of the retina in a quarter second or so, as the tenfold more powerful focused spot of the sun would. But it could do some damage.

Sure would make one unable to see at night for a spell.

I recall a light weapon from the 60's that used a flashbulb in a small reflector that was to be put about 3 ft or closer to one's face and fired, as a nightime get away device.

[nbk2000]

Not all ballons are like the rubber ones you buy at the toy store. A ballon made of suitable polymeric film can retain hundreds of PSI of pressure.

The inverse square rule applies to light sources. Being 2x as far = 1/4 the light intensity, 3x = 1/9, etc. BUT, the apparent size of the light source has a great bearing on the effectiveness in destroying night vision.

A bright light that appears as a point source in the distance isn't going to do squat. But, a bright flash that lights up the entire field of view will cause total disruption.

If the ballon was made in the shape of a disc, rather than a sphere, than you could maintain a constant explosive pressure against the gas, rather than have the decrease in pressure as the shockwave expanded in a spherical manner, since the disc is of a constant thickness across its entire area, relative to the explosive.

A disc ballon is made, with one side being covered with a sheet explosive like det-flex, the other side being clear. The explosive is detonated in the center, and as the explosion radiates outwards towards the edge, it causes an ever-increasing ring of light to be created as the noble gas is compressed into radiating.

This would also extend the length of the flash from microseconds to milliseconds. Might not make a difference, but it may...

So, instead of a spike of light, with a rapid decay (with the sphere), you'd get a rapid build up with a sudden cutoff at maximal intensity (disc).

Exploding an Iso against a dark background (like a tree line) wouldn't be nearly as effective as a light background (like white painted walls). Just using foil or mylar mirroring would greatly increase effectiveness by reflecting otherwise lost light energy back to the target.

As for now, since xoo is trying for proof of concept, it's better to brute force the flash with overkill to get SOME result, rather that to finesse it and fail. Polishing the device to optimize results can come later, after you get the "first light" to encourage further testing.

[xoo1246]

Remove

<small>[ December 11, 2002, 01:23 PM: Message edited by: xoo1246 ]</small>

[xoo1246]

Remove

<small>[ December 11, 2002, 01:19 PM: Message edited by: xoo1246 ]</small>

[nbk2000]

If by center you're referring to the spherical ISO, then you could use the "straw slightly larger than my detonator" trick. Just find a soda straw slightly larger than your detonator, cast/pack your explosive around the straw (the end being in the middle of your charge), and insert you detonator when ready.

Not that hard.

Don't worry about photos. Just look for a bright flash lighting up the surroundings at night. While looking away, of course. :)

Once you've removed the CO2, you'll also have to remove the water vapor. That'll absorb energy by conversion to steam. Passing the purified argon gas through oven-dried silica gel should do nicely.

[xoo1246]

Remove

<small>[ December 11, 2002, 01:18 PM: Message edited by: xoo1246 ]</small>

[rikkitikkitavi]

not if is only a few litres of gas(@ NTP) bubbled through, the high heat capacity of the water prevents any large temperature rise.

There is however two good reason for using a chilled lye-solution

1) gas-liquid reaction is normally speeded with colder liquid due to most gases increase solubility in colder liquid, thus the CO2 is more easily absorbed

2) the vapour pressure (Pwater) of a colder solution is lower than a warmer. And the concentration of water in the gas is Pwater/Ptot regardless of total pressure. So at 1 atm it is about 10/760(you have to look up in a table for the exact value)

You could try to run the CO2-free gas through a PVCtube in a freezer , so most of the vapour condenses ( I assume you dont have a cold-trap and LN2 :) to further dry it. Unless you use a chemical absorbant of course

/rickard

<small>[ August 18, 2002, 05:33 PM: Message edited by: rikkitikkitavi ]</small>

[Xtramad]

There are a lot of explosive replies to your question, but it dosn't have to be that dramatic. Soniluminescence is the easiest solution and it has been shown to work in laboratory tests. Hydrogen bubbles have been hydrosonically imploded (cavitation) creating heat and light (1 million degrees centigrade if I remember correctly) for some nanoseconds. The frequency used was 25MHz I think. The shockwaves from the reaction where dissipated in the test jar so only small amounts of energy where produced. I can't help but think that if these shockwaves where used to feed more such reactions the process might be self supporting.

But anyway, if your interested try searching for:
Zero point energy
Zero point gravity
Soniluminescence
Cavitation
Implosion

Or try these links:
<a href="http://www.calphysics.org/zpe.html" target="_blank">http://www.calphysics.org/zpe.html</a>
<a href="http://www.voicenet.com/~eric/skeptic/ceticrav.txt" target="_blank">http://www.voicenet.com/~eric/skeptic/ceticrav.txt</a>
<a href="http://www.padrak.com/ine/db/DEVICES.html" target="_blank">http://www.padrak.com/ine/db/DEVICES.html</a>
<a href="http://www.und.ac.za/und/prg/sonochem/ultraphy.html" target="_blank">http://www.und.ac.za/und/prg/sonochem/ultraphy.html</a>

[nbk2000]

Soniluminance ism't going to work.

The energy conversion from sound, to mechanical implosion, to luminance is pathetic. You pump in thousands of watts of power and get a barely visible microbubble of faint light.

Explosive pumping of xenon would be infinitely more efficent.

RTPB:

KISS (Keep It Simple, Stupid)

[Xtramad]

Did you wonder where the first post went? I deleted it, and after this one the same will happen to you. DO NOT DISRESPECT THE MODS, ESPECIALLY ADMINS LIKE NBK!

<small>[ August 19, 2002, 03:51 PM: Message edited by: zaibatsu ]</small>

[xoo1246]

Ok, some progress, but moving slow.
<a href="http://w1.478.telia.com/~u47802930/Iso01.jpg" target="_blank">http://w1.478.telia.com/~u47802930/Iso01.jpg</a>
<a href="http://w1.478.telia.com/~u47802930/Iso02.jpg" target="_blank">http://w1.478.telia.com/~u47802930/Iso02.jpg</a>
A bigger container could be used, but I'm having problem finding any suitable(thick walled enough, portable, transparent, cheap, etc.), or possibly I'm not looking hard enough.
Have to find a better cork that can be fitted with a valve without leaking, and finish the washing bottle and a second bottle filled with something to absorb moisture. How would a layer of prilled and dried AN work for water absorbtion? Good enough is my guess.

[Polverone]

Ammonium nitrate might work. Dry calcium chloride or oxide would probably be better. One thing that just occurred to me: can you test the "goodness" of the purified gas by firing a spark through it? Okay, maybe you don't have any high voltage equipment around. But I would think that brighter sparks from electricity would be indicative of more light from shock heating, since in each case you're going to have a better peak temperature with a purer noble gas. Even disposable cameras make a pretty good flash with just a little bit of xenon and a modest capacitor. Hmm, starting to wonder what you could do with a big cap bank and a homemade giant flash tube...

[Spudgunner]

A line and a half is the longest sentance you have ever written? Are you under 12? Or is it that English isn't your native language and you have never written that long of a sentance in English?

Anyway, setting them off at the same time shouldn't be THAT hard, just use the EXACT same length (and gauge) of wire to your caps, make the caps the EXACT same each time. Or, use exactly equal lengths of det cord, thus the electricity (or the shockwave) will get there at the exact same time as they have to travel the exact same distance.

Spud

[Anthony]

I don't see why you'd use shaped charges as there is nothing that the liner needs to penetrate. It would be better to just use the monroe effect of the colliding shockwaves.

[nbk2000]

Well, after further researching, I've found some interesting tidbits.

Firstly, argon isn't the only gas that can be used. Any mono or diatomic gas can be used. The higher the molecular weight and/or pressure, the better the flash.

Helium, argon, xenon, hydrogen, neon, krypton, and even plain old air (nitrogen) will work.

The gas will emit whatever spectra it would if energized in an electric tube, like a neon light. So, xenon would be blue-white, neon red-orange, etc.

The munroe effect can be used to amplify the intensity of light emitted because of the highly concentrated shockwave it emits. The important thing is that there be no liner and the cone is itself filled with the desired gas.

The duration of the flash depends on the distance the shockwave has to travel from the explosive to the casing, at which time it ruptures the container and ends the flash effect. The further away the tranparent casing is from the charge, the longer the flash effect.

Any decent HE will work, such as TNT or Picric Acid, so you don't have to have RDX or HMX to make it work (though bigger is always better <img border="0" title="" alt="[Wink]" src="wink.gif" /> ).

I've come up with an idea that might allow for very long flash time, relative to current devices.

Rather than a spherical charge, use a tubular charge. Imagine a hollow tube (like a straw) with a very high length to diameter ratio. Something like 5 feet long to 1 inch around (for instance). The entire inner surface of the tube is lined with a sheet explosive for its entire length.

The tube is filled with argon or such under very high pressure, with one end capped with a detonator assembly with a waveformer to cause the explosive shockwave to travel the entire length of the tube at an equal rate, like a ring, to the opposite end which is capped with a clear window for the light to escape.

As the shockwave travels down the tube, it implodes towards the center, compressing the gas into luminensce. Also, as the shockwave races towards the end, it compresses the gas that way too, increasing the pressure even more.

You don't have to worry about any gas escaping out the blown end because the shockwave has something like 10,000,000 PSI of pressure, MORE than enough to retain the argon in place for the few thousandths of a second the device will exist. :)

So, instead of a flash duration of 1/1,000,000th of a second, you could get (assuming 7,000m/s explosive velocity at 2 meter length) have 1/3,500th of a second duration.

It might even be possible to build this in a laser configuration using helium-neon or such, line with a highly reflective liner material like silver, with a 98% mirror instead of a clear widow. Explosively pump the gas into lasing and direct as needed.

Given the insanely high energy levels decent explosive liberate in microseconds, you could get, even with crappy conversion rates of 1%, several watts of laser energy. A few watts doesn't sound like much, but 5 watts of IR energy will burn through steel plate. <img border="0" title="" alt="[Eek!]" src="eek.gif" />

Direct a beam of visible laser light at a gathering of people at night from miles away, and you could likely blind them, if not permanently, then at least temporarily.

Because of the distance, you'd be well outside of any security perimeter, thus politicial rallies, celebrity gatherings (oscars?), sporting events...all present high profile target opportunities.

Or, blind the cockpit crew of an airliner as they're landing. Crash and burn baby! Who needs boxcutters when you've got a HE pumped pulse laser? :p

<small>[ October 20, 2002, 07:16 AM: Message edited by: nbk2000 ]</small>

[vulture]

I'm afraid nitrogen gas won't work, as ionizing N₂ requires breaking the triple bond which requires an energy of about 800kJ/mole and that's a shitload of energy, there will almost be no light emitted. This goes for all diatomic gasses, although N₂ has a somewhat extreme enthalpy.
It's not because noble gasses are inert and N₂ is also inert to most chemicals that they show the same ionisation behaviour.
This depends largely on valence and binding properties.

[nbk2000]

The patents specifically mention "air". Now, I'd figure that to mean the nitrogen in the air, which constitutes the vast majority of the stuff, but it might be from the other gases listed, like the hydrogen and argon.

Regardless, it works with plain ol' air. Just not as well as argon.

I wonder, is there a gas that'll emit IR? I know CO2 is used in IR cutting lasers, but would it disassociate under explosive force? I believe it would.

[nbk2000]

Another idea:

Personal body shields that have small discs (&lt;5 grams) of a sheet explosive like det-flex covered with a plastic bubble filled with xenon. These discs sit on a pumice foam layer to absorb the shock. There is no direct contact of explosive with the shield that might weaken it.

When facing an adversary in darkness, you can trigger a disc, blinding anyone in the immediate area in front of you, while the shield protects you from the flash and blast. Since there's multiple discs, you can trigger them as often as needed.

Since the shield is bullet-resistant, and the explosive shock sensitive, any bullet strikes on a disc will immediately set it off, flashing your attacker, while the shield stops the bullet.

The use of shields made from lightweight bullet-resistant paneling goes towards a concept of highly armored criminals, much like the LA bankrobbers, only better. :)

[Dave Angel]

"for a leyden jar to store a farad at just say 10KV you'd have a jar the size of a small town!"

Or maybe a storm cloud...

http://www.roguesci.org/theforum/showthread.php?t=1815

After reading through the thread on attracting lightning, I wondered if one could combine these ideas. Connect the ground end of the conductive wire on the rocket to a cylinder of argon and use a lightning bolt to initiate the iso pulse.

It's probably not as simple as this, as the bolt could earth around the metal casing of the cylinder 'ignoring' the argon within. The container may not even rupture.

Perhaps a non-conductive container with metallic points at the top (wire attached) and bottom (ground) to guide the bolt through the argon. Putting a fine wire between the two points could make sure of this.

Of course, the first example would be more desirable if it could work, due to the simplicity, and that your kilo of argon is pre-pressurized, most likely at a higher pressure than one can create with ones own container.

[JoeJablomy]

COIL - chemical oxygen/iodine laser, right? I never understood how they got these to work. It is my understanding that it reacts atomic oxygen with iodine vapour to cause the population inversion required for lasing. BUT, how do they keep the atomic oxygen atomic?! I've seen a demo (in fact, the same demo is shown on a site which I think I got to from a link here somewhere...) where chlorine is passed through 30% H2O2 to produce atomic oxygen, which very soon recombines and causes a deep red chemiluminescence. I don't know how they stop it from doing this for long enough to get it into the lasing cavity?

It isn't atomic oxygen, it's an electronically excited state of O2 ("singlet oxygen") that has about the right energy for near IR lasers but is actually too stable to effectively lase, or something to that effect. The iodine gas is atomic, and has an appropriate metastable transition, and the singlet O2 transfers energy to it. I get the impression that COILs operate at a low internal pressure to reduce the incidence of the singlet O2 undergoing a pooling reaction to ground state and a less stable form that spontaneously emits at, I believe, 730 nm. To give you an idea of the complexity of this chemical system that someone had to come up with, the less stable O2 species actually serves to split the I2 gas that goes into the chamber into atomic I gas.

[matjaz]

...The gas will emit whatever spectra it would if energized in an electric tube, like a neon light. So, xenon would be blue-white, neon red-orange, etc...
NBK, Not meaning to be a smart-ass but I just stumbled across this. Actually, at high pressures, it doesn't work this way. The mean free path of atoms/molecules is so short, that the next colission occurs before the entire "photon" would be radiated away in a neat wavepacket of a defined color. This cuts the wavepackets short and thus broadens the spectral lines so much that you get a very continuous spectrum, depending mostly on the temperature, not on the original charasteristic transitions (as known from low pressure applications).

I wonder, is there a gas that'll emit IR? I know CO2 is used in IR cut...
Again, at extreme temperatures and pressures, other mechanisms govern light output. If the excitation level of an atom is high enough for a visible or even a UV photon, it will do it, rather than climbing down slowly via many IR transitions, even if they were possible.

So unless a very exotic material is fashioned, any IR output must be accompanied by a vast amount of visible and UV energy.

[JoeJablomy]

NBK, Not meaning to be a smart-ass but I just stumbled across this. Actually, at high pressures, it doesn't work this way. The mean free path of atoms/molecules is so short, that the next colission occurs before the entire "photon" would be radiated away in a neat wavepacket of a defined color. This cuts the wavepackets short and thus broadens the spectral lines so much that you get a very continuous spectrum, depending mostly on the temperature, not on the original charasteristic transitions (as known from low pressure applications).

I believe what the reference at the start of the thread said was that the spectral bands were broadened into effectively white light. This is a doppler effect where the emitting molecule is moving toward or away from the direction that it emits in and the energy (thus wavelength) of the photon is changed. The hotter it is, the wider the emission bands.
Under what theory can photons be cut "short", implying a shorter wave, and have less energy? What is a "wavepacket"?

If the excitation level of an atom is high enough for a visible or even a UV photon, it will do it, rather than climbing down slowly via many IR transitions, even if they were possible.
Only if it has a higher tendency to make that transition. Lasers would not be possible if all particles behaved this way; according to your statement, both three state and four state cycles would be impossible because the emitters would go directly to ground state rather than stopping at the second and/or third states.

[Guerilla]

Dave, that sounds like an interesting idea.

However, would this actually result in any brighter flash than a normal lightning strike has? That is, with such an insane amount of voltage the gas sure would get ionized *completely* but after that the current would just run through it, resulting in maybe a relatively prolonged (due to high ionisation potentials noble gases have compared to air) and different colored but not noticeably brighter flash, no?

Anyways, I'm willing to carry out a similar test if nothing else then as an exciting experiment; the idea of attracting lightning fascinates me. ;) Last summer I happened to be around 100m from a lighting strike, it really blinds you for a few secs even if you don't look straight at it, I don't think it's much of a risk to a camcorder though.. Instead of a rocket and a pressurized cylinder I thought I would just use a 20-30l helium filled balloon that has two pieces of foil on both sides as electrodes, the lower one grounded with a 50-100m long copper wire. There could also be a smaller balloon hanging above, tied to the upper electrode with a bare conductor, making the current more likely to move through the gas. The whole event could safely be observed from inside a car without having to be too far from the grounding zone.

[Dave Angel]

"would this actually result in any brighter flash than a normal lightning strike has?"

Hmm, I'm not sure, but it would be fun to find out! I wonder what it would do?

Look at the brightness of a lightning bolt arcing through atmospheric gas at atmospheric pressure. Some of the energy goes into breaking molecular bonds and yet it is still so bright. With pressurised argon, no bond breaking is involved and there's a lot more gas around to get ionized...

A longer flash, different colour, maybe brighter? Perhaps with all that hot gas needing to expand, one might create an incredible thunder clap. But who knows? There could be some counter-intuitive things going on here and physics isn't my best subject.

Worth trying for the whole 'Frankenstein Feeling' anyway. Good luck with your attempt.

[matjaz]

This is a doppler effect where the emitting molecule is moving toward or away from the direction that it emits in and the energy (thus wavelength) of the photon is changed. The hotter it is, the wider the emission bands.That's another broading mechanism, yes. It works also in hot gases at low density.

Under what theory can photons be cut "short", implying a shorter wave, and have less energy? What is a "wavepacket"?No, less energy would be longer waveLENGTH. I meant shorter WAVE, hence bigger uncertainty in wavelength. (To answer: With wavepacket I meant a photon here. And if I really must pick a name for the theory, it would be QED.)

Lasers would not be possible if all particles behaved this way; according to your statement, both three state and four state cycles would be impossible because the emitters would go directly to ground state rather than stopping at the second and/or third states.Because you don't have a high temperature there, just a dense flux. If you pumped the level distribution to a much higher temperature (with forced implosion, etc), ionize even, the steep energy dependence of the transition probabilities would prevail over the multipolarities, I think.

Oh, just thought of another broadening mechanism. When the gas is ionized (hi-temp), you can do "transitions" where enegies are continuous in principle, because you can move between the continuum states (free electrons) and bound states (defined energies).

[Jacks Complete]

Any blackbody radiation is going to put out a large portion of it's energy output as IR. Pushing more energy out requires going further up the temperature scale, and hence shifting the peak wavelengths. This still increases the IR energy further, meaning things get very inefficient very quickly - less than 10% of a hundred watt light bulb is actually visible light.

You have to do clever things with atomic spectra and re-radiative absorption, etc. to sway things so that the energy is output as what you are after - hence the massive numbers of Krypton and Argon bulbs, which shift the IR up into the visible using photon recombination (iirc)

Lasers and semiconductor devices avoid this by using a different light output mechanism, leading to greater efficiency (not that most lasers are anything like efficient, unless looked at from the brightness at a required frequency) by not wasting lots of power via the majority of the black body spectra.

The downside to the laser approach is that throwing more power at it generally doesn't work. Think along the lines of a sensitive scale - you can use more force or less force, but there is only one right answer!

Anyway, to outshine the sun, the simplest way is to cheat, and get a diode laser pointer, which will be ten million times brighter than the sun at the chosen output wavelength. The other way is to go and buy a 5 million candlepower lamp. Mine is charging upstairs right now! It is intense, to say the least.

Vulture,
the N2 triple bond can be broken, and when it reforms, it outputs in the UV part of the spectrum. It also self-terminates very rapidly, so much so that you can't make a normal laser from it, as the beam would re-absorb before it got out the tube! However, the ability is there, and you can use it with the right design.

[Marvin]

Nitrogen does not require the triple bond to be broken in order to ionise, nor does it require to be broken or ionised to lase. The efficiancy of a UV nitrogen laser is very very small though 0.1%ish IIRC making the output energy per pulse very small indeed. Furthur more as you increase the pressure collisional deactivation reduces the lifetime of the excited state even furthur, and its allready too fast for anything but special electronic methods. The gas being excited by the shockwave would be too turbulent to lase even if a method were found to get the shockwave through the gas within a few nanoseconds....

The energy in a a HE is usually less than a typical pyrotechnic mixture, and the energy in the shockwave is small compaired to the total chemical energy released. In terms of generating a bright flash I dont see any real advantages over a flash powder unless the short pulse is being used to optically pump a laser.

If someone was after temperary blindness, using visible light would be essential, but for perminant eye damage theres no advantage.

matjaz,
Nice idea about uncertainty caused by 'cutting short' a photon, but that would require the emitting species to be left in an equally uncertain state to avoid conservation of energy problems. Since its limited to discrete states this cant happen. I think you are confusing lifetime broadening with collisional broadening. Collisional broadening is based on the location of neerby atoms affecting the energy levels of the orbitals. We still assume that absorption and emission happens much faster than the movement of atoms (Franck-Condon Principle). Your statement about lifetime of excited states decreasing with increasing energy doesnt affect the initial statement about UV and visible decays - which is allready a specific energy band, though its a valid point for anyone trying to make X ray lasers. UV/Vis transisions are heavily influenced by spin and symmetry rules. Increasing the termperature (like increasing the pressure) would decrease the probability of seeing a rare transition, not increase it, because there is a greater chance of collisional deactivation/intersystem crossing making alternative emission (in stages) much more likley.

[Jacks Complete]

Marvin,
I think the OP is not going to work. At least, not in a non-military setting.

You can actually make a single mirror UV pulse laser that will work just by taking the O2 out by combustion, then absorbing the CO2. Apparently the remaining N2 is pure enough that you can make it lase with a flashlamp and a pulsed lamp. The biggest problem is that the lamp is massively inefficient, before you get anywhere near the Nitrogen!

There is an Amateur Scientist column from SciAm on it, somewhere, but I don't have it in full any more.

[Marvin]

You have the right idea, but the N2 laser cannot be optically pumped. Lifetime of the excited state is around 25ns, lifetime of what it drops to is in the 10's of us. Add a cavity and you only have gain for about 6 or 8ns. Practically the only way to get energy into the N2 this fast is to build a flat plate capacitor and have an N2 discharge area built into one of the edges, ie transverse discharge rather than lengthways through the gas as in ordinary lasers.

An 8ns long pulse of light has some uses, like bullet stopping flash photographs, but its very difficult to focus and low pressure N2 has a crappy energy density anyway (for a laser).

[Jacks Complete]

You're right... I was getting confused between the dye laser and the N2 laser! Now you mention the flat plate capacitor, I recall it a bit better. I wish I still had that article. (see below)

It's a flat bit of double sided PCB, etched into a sort of flat plate, with the gas flowing down the center of one side. The article reckoned you used a vacuum pump to drop the N2 pressure far enough for it to spark, and then the gas flowed out, and was replaced, and it would fire again (iirc, again that might have been the dye laser).

I'm going to go and try to get a copy of the article. It was in a collection of plans called "Light and it's uses"

EDIT: In fact, I just found a photo- http://www.repairfaq.org/sam/ccn2ls.jpg
and the plans - http://www.repairfaq.org/sam/n21asm.gif
as well as a lot more detail than you will need for something like this - http://www.repairfaq.org/sam/lasercn2.htm

Seems you can't lase the air, much as I thought, due to the O2 stopping it in concentrations above 1%, though someone says that about .3% O2 can actually improve performance.

[Jacks Complete]

Just had to post a boast on here.

I have just got my hands on two rather lovely things that can outshine the sun. I've got a 5 million candlepower spotlamp and a 5mW Green laser pointer. Both are brilliantly cool toys.

The lamp is insanely powerful, easily lighting a room up in daylight, and capable of shining right through post, hands, etc. Gets hot quite fast though...

The laser is great, you can light a tree up at a mile without any trouble, and you can even see the beam through the air at night. Seriously bright, and very coherent, with a very low divergence (beam spread)

I'm going to be building the dye laser soon, since I have got some great dye of of eBay. I'm still trying to find a chemical supply house nearby, though...