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Nitrogen 'Diamond' Created

michael posted about 10 years ago | from the squish dept.

Science 73

Sensible Clod writes "Researchers of the Max Planck Institute for Chemistry have synthesized a new form of nitrogen, with a stucture like that of diamond. This was accomplished by means of a crushing force (>110 GPa) at extremely high temperature (2000 K), of course. The result, according to PhysOrg, is a very hard crystal with a lot of energy stored in it, which leads to the possibility of using it as a non-polluting fuel or high-explosive."

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Properties? (5, Insightful)

justanyone (308934) | about 10 years ago | (#10505432)


Several Questions:
1. Translucent?
2. Melting point?
3. Stable at STP ?
4. Does It Burn if I touch a match to it? Explode?
5. Does it resemble N2, which is stable, or not?
6. What is the hardness level (Mohr's scale) ?
7. Will it degrade over time under exposure to water?
8. Is the method for creating it highly expensive or could this be scaled up?
9. If it is explosive, how do we store it safely?
10. What are the mechanical properties? If it's stable and otherwise useful, will it vibrate with a piezoelectric effect?
11. Is it a semiconductor, conductor, or insulator?
12. Does it lase (can we use it as a pump medium for a laser) ?

Re:Properties? (4, Interesting)

the morgawr (670303) | about 10 years ago | (#10505483)

From reading the article, it doesn't sound like they've gotten the material to stay that way at room temperature and pressure yet, so measuring much that stuff would be difficult.

Ummmm, Dunno (0)

Anonymous Coward | about 10 years ago | (#10505842)

Why don't you make one and test it? Let us know how it works out :^)

Re:Properties? (4, Insightful)

Kozar_The_Malignant (738483) | about 10 years ago | (#10505918)

From the article:
"First of all, we should try to recover the compound to ambient temperature and pressure", Eremets says.

Translation: "It spontaneously goes poof (or kaboom) when we release the pressure in the machine."

Re:Properties? (4, Funny)

Shadow Wrought (586631) | about 10 years ago | (#10506177)

Just mod the answers down now. It'll be easier for all conerned...

Several Questions: 1. Translucent?

No but it is transqwest.

2. Melting point??

Typically comes after an expensive dinner and a little champagne.

3. Stable at STP ??

No but it does keep horses in the Quaker State.

4. Does It Burn if I touch a match to it? Explode??

Only when the match is lit.

5. Does it resemble N2, which is stable, or not??

It more closely resembles Not, stability notwithstanding.

6. What is the hardness level (Mohr's scale) ??

It rates a 2.7 on the Less is Mohr scale.

7. Will it degrade over time under exposure to water??

Sort of. It gets these prune like wrinkles in its outer fringes...

8. Is the method for creating it highly expensive or could this be scaled up??

Cheaper than antimatter, but more expensive than pirated CD's.

9. If it is explosive, how do we store it safely??

We'll figure that out once we have them produced in order to build on the success of our nuclear storage program.

10. What are the mechanical properties? If it's stable and otherwise useful, will it vibrate with a piezoelectric effect??

As for the former, it owns two car repair joints over on the East Side, as to the latter, uhhhhh, sure.

11. Is it a semiconductor, conductor, or insulator??

It has a part time gig with the Philharmonic, so it is a semi-conductor.

12. Does it lase (can we use it as a pump medium for a laser) ?

It lazes very well, especially on Sundays during football season.

Re:Properties? (2, Funny)

nartz (541661) | about 10 years ago | (#10510989)

9. If it is explosive, how do we store it safely??
In Nagasaki and Hiroshima.

Re:Properties? (1)

Waffle Iron (339739) | about 10 years ago | (#10506225)

It's going to take some time to determine those properties. The researchers are proceeding very cautiously because they don't want to end up like Mikey, who was also working with gasses packed into a solidified form.

Or better yet... (4, Funny)

El (94934) | about 10 years ago | (#10505438)

"Here honey, but this diamond ring on and then go punch that wall..."

But the trick is always... (4, Insightful)

Banner (17158) | about 10 years ago | (#10505448)

Getting the energy out in a controllable stream, not all at once. It's not the storage of energy that is ever the issue: Capacitors and high-explosives store lots. It's just getting it out the way you want it that is the trick.

Re:But the trick is always... (4, Insightful)

Ayaress (662020) | about 10 years ago | (#10505966)

I guess that's why they listed high explosive among the uses. Even if you can't control the blast whatsoever, if it blows up, you can find a use for it.

Re:But the trick is always... (1)

NanoGator (522640) | about 10 years ago | (#10506213)

" It's just getting it out the way you want it that is the trick."

I'm itching to do a Wile E. Coyote joke, but I haven't had my coffee yet.

Re:But the trick is always... (3, Informative)

iwadasn (742362) | about 10 years ago | (#10508177)


High explosives don't store that much. If I remember correctly, TNT for instance has less energy than gasoline. It's not so much about the quantity of energy in an explosive, but rather the rate at which it can be released.

Re:But the trick is always... (0)

Anonymous Coward | about 10 years ago | (#10515145)

Nitrated compounds always tend to release energy very, very fast. The draw of creating 3 bonds increases the rate and energy. This is why many explosives are just creative ways of storing and arranging nitrogen so it can be released ultra fast to form N2.

Since this is purely nitrogen, N2 production is basically assured, and there is no way to pack in more nitrogen since it's entriely (single bonded) N atoms. It is, in a sense, the perfect energetic material (except perhaps from a storage and controlability standpoint).

Re: But the trick is always... (1)

Black Parrot (19622) | about 10 years ago | (#10509288)


> Getting the energy out in a controllable stream, not all at once. It's not the storage of energy that is ever the issue: Capacitors and high-explosives store lots. It's just getting it out the way you want it that is the trick.

Maybe they should make the crystals out of lithium-2 instead of nitrogen.

Re:But the trick is always... (0)

Anonymous Coward | about 10 years ago | (#10510983)

Uh. Yeah. Getting energy out of capacitors the "way you want it" is actually very easy.

a rock and a hard place (1)

Doc Ruby (173196) | about 10 years ago | (#10511530)

The real question is the efficiency of storing it. If it stores megajoules in cubic centimeters, but takes gigajoules to create, it's not such a safe bank in which to invest our energy. In which case it's good only as a bomb, and we've just invented a great way for countries to develop WMD without either nuclear tech sophistication, or critical factors like fissionables or klystrons. And even if it's an efficient battery, the transfer of energy into it will undoubtedly produce pollution. This is one big black cat out of the bag.

Re:a rock and a hard place (0)

Anonymous Coward | about 10 years ago | (#10516902)

But I like big black cats!!

yeah yeah, but we all know .. (1)

torpor (458) | about 10 years ago | (#10505460)

.. diamonds of purest nitrogen, holy of holies, won't be cheap enough for us mortals to own and use until the .. erm .. porn industry .. works out .. a use for it ..

*ahem*

Fuel? Baah. (5, Funny)

arkham6 (24514) | about 10 years ago | (#10505492)

A fuel? How much less energy do you get out from it than was put into it? It seems like a very difficult way of wasting energy.

Re:Fuel? Baah. (1)

smileyy (11535) | about 10 years ago | (#10505998)

Currently[*] all fuels give back less energy than was put into them. There are times and places where size and mass may be at a premium, e.g., launching something into space. [*] and by "currently", I mean "eternally"

Re:Fuel? Baah. (1)

marcus (1916) | about 10 years ago | (#10506003)

So is a common everyday chemical battery of any type, yet they are in use all over the world.

Re:Fuel? Baah. (1)

caseih (160668) | about 10 years ago | (#10506361)

Well all batteries do a terrible job of capturing the charging energy. The important thing is how much total energy it can store, and how efficiently it can release it. Losing energy during the charging conversion process is really unimportant.

Re:Fuel? Baah. (3, Insightful)

JohnPM (163131) | about 10 years ago | (#10508210)

Think rocket fuel. The weight is critical to how much fuel you'll need. Lighter fuels are invaluable even if it takes heaps of energy to generate them.

Reminds me of... (5, Interesting)

reverseengineer (580922) | about 10 years ago | (#10505663)

This seems somewhat like a what a polymerized azide ((N3)- ion)compound would be like, perhaps with many similar properties- I can see the uses as a high explosive, as sodium azide is generally the explosive in airbags- a couple grams of the salt is sufficient to generate over 50L of nitrogen gas quite rapidly. The rearrangement of this network solid into triple-bonded gas molecules should release an enormous amount of energy. I wonder if this is nearly as sensitive to shock as the azides are though.

Re:Reminds me of... (1)

Kobal (597997) | about 10 years ago | (#10505897)

And here I thought what was in airbags was either silicone gel or a saline solution...

Re:Reminds me of... (4, Informative)

cryptochrome (303529) | about 10 years ago | (#10506011)

Well there is also the slight problem with the fact that azides are EXTREEEEMLY nasty. Here's the short warning:

Sodium azide is extremely toxic (LD50 oral [rat] 27mg/kg) and a powerful poison. Ingesting very small amounts can cause death in a short period of time. When mixed with water or an acid, sodium azide changes rapidly to a toxic gas with a pungent odor. However, the odor may not be sharp enough to give people sufficient warning as to the hazard. When heated to its decomposition temperature of ~275C, sodium azide may undergo violent decomposition. Additional hazards: Sodium azide also changes into a toxic gas when it comes in contact with solid metals. Sodium azide reacts violently with nitric acid, bromine, carbon disulfide, dimethylsulfate, and several heavy metals including copper and lead. Never flush sodium azide (solid or concentrated solution) down the drain -- the azide can react with lead or copper in the drain lines and explode. Do not store on metal shelves or use metal items to handle sodium azide (i.e., spatulas). Contact with metal shelves, containers, and utensils can result in formation of heavy metal azides and the risk of explosion.

Most of these issues stem from the fact that azide packs a very large amount of energy in a very reactive compound. I would imagine nitrodiamond dust could have issues as well. Although a state change between the solid and gas forms would produce no pollution, it could potentially be reactive with other compounds, like oxygen and carbon dioxide.

Do Not Taunt! (4, Funny)

justanyone (308934) | about 10 years ago | (#10506297)

Do Not Taunt Super-Happy-Fun-sodiumazide.

Re:Reminds me of... (2, Informative)

Muhammar (659468) | about 10 years ago | (#10511791)

You are exaggerating wildly. I work with sodium azide frequently and it is not terribly dangerous or poisonous material.
Extremely toxic is stuff that will make you ill (dead) from ingestion/inhalation of tiny amounts - like from having few whifs of vapor, licking your fingers or spilling few drops on your sleeve. Or something that accumulates over repeated exposure. If the tox from rat scales to human, 27mg/kg 50% mortality means that a grown man (80kg) would have to ingest something like 2g of the stuff for having a 50% chance of getting stiff. It is hard to ingest such amount without doing it on purpose. You can find much worse stuff than azide in a normal lab.

As far as not using metalic spatulas for sodium azide, this is way overboard. Copper and other heavy metal azides are very impact sensitive but their formation because of stainless steel spatula is not an issue. Bulk storage (preferably not in a metal drum) is another thing.

Every bottle of chemicals in US has wildly exaggerated warnings because of manufacturers liability. Acetylosalicylic acid (=aspirin) has warning: toxic-target nerves, thyroid. Benzaldehyde (food and fragrance almond flavor, present in cherry cola, soap and champoo) is labeled highly toxic if you buy it as chemical. Bottle of pure sand has warning "this material is known to state of California to cause cancer" etc.

Re:Reminds me of... (1)

cryptochrome (303529) | about 10 years ago | (#10513150)

Yes, but the context of the article is of using these rather potent substances as propellant or high explosive. Many of those applications involve rather more than a few grams.

Incidentally, we use sodium azide in my lab too. No deaths, but it does have the nastiest warning on the side of the bottle of all our chemicals. Except for that one bottle of ricin [cdc.gov] , which is potentially fatal with a mere 0.5 milligrams.

Re:Reminds me of... (1)

Nyrath the nearly wi (517243) | about 10 years ago | (#10513249)

Amusingly enough, something like this was predicted [technovelgy.com] by SF author E.E."Doc" Smith back in 1931.

non polluting fuel my ass (1, Redundant)

Splork (13498) | about 10 years ago | (#10505718)

look at the amount of resources that had to be spent just to get it into this form!

Re:non polluting fuel my ass (3, Insightful)

EdwardElric (799642) | about 10 years ago | (#10506489)

Every fuel takes more energy to produce than you can get out of it. This will be true whether the fuel is ethanol or anti-matter. It's the second law of thermodynamics.

What makes a fuel non-polluting is the waste products. A fuel that, when used, gives off water is non-polluting compared to a fuel that gives off carbon monoxide. In this case, if the polymeric nitrogen could be converted to the more stable triple-bonded molecule, you would get common molecular nitrogen and a lot of energy. Thus, this has the potential to be a non-polluting fuel source.

Re:non polluting fuel my ass (1)

WolfWithoutAClause (162946) | about 10 years ago | (#10507176)

Doesn't that depend on where you get the energy from in the first place? If they are right next to a nuclear power plant or a windmill or a hydroelectric generator and they use that power then there is no net carbon dioxide production.

Still, they haven't produced a crystal that survives at STP- as soon as they remove the pressure it goes back to being gas again- I don't know about you, but I don't usually carry a diamond anvil around in my car. It isn't a practical fuel, or energy storage technique at present.

Metallic Hydrogen next, please... (0)

Anonymous Coward | about 10 years ago | (#10505877)

Of course I'm probably the only one who read the book...

Re:Metallic Hydrogen next, please... (1)

julesh (229690) | about 10 years ago | (#10512076)

Not sure what book you're talking about but metallic hydrogen [wikipedia.org] has been around for quite a while.

Re:Metallic Hydrogen next, please... (0)

Anonymous Coward | about 10 years ago | (#10517562)

Sorry, I was thinking about "Metastable Metallic Hydrogen", which stays solid even if you take the pressure away.
I can't remember the book's title (and it was in German anyway), but it was a SF story about the exploration of a planet where an expedition found metallic hydrogen just "lying around".
The resolution was, that the whole planet was artificial, it was hollow, it had tides without a visible moon because it was inside the planet, and the metallic hydrogen was a by-product of the black-hole based energy source in the core of the planet...

fuel, my ass! (2, Insightful)

museumpeace (735109) | about 10 years ago | (#10505925)

This is like Bush talking about using hydrogen to solve the looming oil shortages...
How much energy do you put in to the process and the material compared to the amount you can get out of it? These uneconomical fuels are a half assed notion that only have real applications where weight or efficiency are hard constraints and money is not, i.e. space craft propulsion.

Re:fuel, my ass! (4, Informative)

j_cavera (758777) | about 10 years ago | (#10506346)

Fuel as in energy storage, not energy generation. Fossil fuels give net energy (but not by much) because they naturally exist in an unstable state. Nitrogen naturally occurs in its most stable state, so no net energy by burning N2. But put it into polymeric form and you have a strained lattice storing tons of energy, read: rocket fuel. As a comparison:

2 H2 + 02 -> 2 H20 12.6 MJ/kg
N4 -> 2 N2 60 MJ/kg (est.)

Other, even higher energy (non-nuclear) fuels include:

Metallic Hydrogen: 2 H(s) -> H2(g) 138 MJ/kg
Free-Radical Hydrogen: H + H -> H2 104 MJ/kg
Metastable Helium: He* -> He 480 MJ/kg
Ionic Hydrogen: H(+) + H(-) -> H2 835 MJ/kg

As much fun as you can have without going nuclear...

Re:fuel, my ass! (1)

museumpeace (735109) | about 10 years ago | (#10507822)

hmmm thats interesting. Ionic hydrogen couldn't be that easy to handle though could it? Seems like its just protons and would want to a plasama or one bad-ass acid. Didn't sound like the single bonded N was very stable either but I am not sure I was getting the article straight.

Re:fuel, my ass! (1)

j_cavera (758777) | about 10 years ago | (#10508396)

Storing hydrogen ions is a *huge* problem as you can well imagine. Some thoughts include magnetic confinement (probably more trouble than its worth) or as frozen, monoatomic hydrogen snow in a bath of liquid helium (also ranking in the "yeah, right" category). NASA (formerly Lewis) Glenn Research Center has done some on the hydrogen snow idea, but hasn't gotten very far.

Polymeric nitrogen will (hopefully) be stable once released from captivity. No one knows for sure though ...

Re:fuel, my ass! (2, Funny)

museumpeace (735109) | about 10 years ago | (#10508646)

...Polymeric nitrogen will (hopefully) be stable once released from captivity. No one knows for sure though ...

OK, you do the experiment, I'll read [or hear] the report;)

Re:fuel, my ass! (1)

Christopher Thomas (11717) | about 10 years ago | (#10509058)

Storing hydrogen ions is a *huge* problem as you can well imagine. Some thoughts include magnetic confinement (probably more trouble than its worth)

For space applications, you could use a large wire loop to make a big and _light_ dipole magnet, and store the ionized hydrogen in the extended side lobes (much as particles are trapped in Earth's van Allen belts). Density is low, but it's mass of the craft that matters, not size. You can only use it slowly, but that isn't a big disadvantage either (it's only launch that requires high thrust; high-Isp, low thrust drives are perfectly acceptable once you're in space).

You could use two dipoles like this that were of opposite polarity and tethered axially, to store both types of ion. Reel in the tethers, and there's enough leakage between the gas toruses for reaction to occur. As long as you can set things up so that there's a favoured direction for production (different sized magnets?), the resulting energetic neutral hydrogen makes a very nice rocket plume.

Alternatively, you could use three coils and do a solenoid with two field bulges separated by a pinch, but that's worse for long-term containment.

I'm kind of wondering where the energy goes when you react two ions in vacuum, though. I think you'd either get it dumped as light (not very useful for a space drive), or you'd get H2+ and one of the electrons kicked off at high speed to shed energy (which means the reaction product is charged, and so affected by your containment field). Can anyone who's actually studied monatomic H+/H- reactions clarify this for me?

In summary, I think the problem is solvable in a way that's useful for a space drive.

Re:fuel, my ass! (3, Informative)

Vellmont (569020) | about 10 years ago | (#10508351)

Not to pic nits, but fuels can be used to produce energy because they're not in the lowest energy state, not because of instability. Endothermic reactions can result from instability, but absorb energy.

Re:fuel, my ass! (0)

Anonymous Coward | about 10 years ago | (#10511770)

A good rocket fuel does not care how much energy is released, it more cares about increasing in volumne as quickly as possible. Some of this is done by increasing temperature (energy) but a good rocket fuel gives off more moles of "product" than there are of the "reagent". I can't think of any examples right now but you guys needed to be stoped talking about energy release when you need to be talking about explosive power as a massive and rapid increase in volume (which is the definition of an explosive as I recall)

Re:fuel, my ass! (1)

Christopher Thomas (11717) | about 10 years ago | (#10516280)

A good rocket fuel does not care how much energy is released, it more cares about increasing in volumne as quickly as possible.

A good rocket fuel cares only about exhaust velocity. This is a function of the number of moles of exhaust product, and their kinetic energy (temperature).

All of the fuels described above have spectacularly good Isp despite having few moles of reaction product, because energy per mole of product is huge, and the molecular weight of the products is very low compared to most things (H2O has an atomic weight of around 18, while H2 has an atomic weight of 2 - meaning at the same temperature you get about 3x the exhaust velocity (and Isp) from expanding molecular hydrogen than expanding steam).

In summary, energies this high help a _lot_, number of moles notwithstanding.

Re:fuel, my ass! (1)

X-rated Ouroboros (526150) | about 10 years ago | (#10513550)

Metastable Helium: He* -> He 480 MJ/kg

As much fun as you can have without going nuclear...

Isomeric transition is a nuclear process.

Re:fuel, my ass! (1)

Christopher Thomas (11717) | about 10 years ago | (#10516236)

Metastable Helium: He* -> He 480 MJ/kg
As much fun as you can have without going nuclear...


Isomeric transition is a nuclear process.

This isn't a nuclear isomer - it's an electronic isomer. Helium normally has both electrons in the 1s orbital with opposite spins. He* has one in 1s and one in 2s, with the same spin, so there's no one-photon decay path. This state is therefore much more stable than most excited states (half life of around 2.3 hours if undisturbed).

Keeping He* contained is another matter. If it can interact with other matter - even itself, if in a disordered gas - that hastens the decay process by allowing other decay modes that involve exchange of angular momentum with other atoms. There was an interesting study about binding it as molecular helium with He + He*, and attempting to keep spins stabilized by applying a strong external field, but funding was cancelled for that (review board didn't think it had enough chance of working to continue studying it past the review time).

Re:fuel, my ass! (2, Interesting)

Christopher Thomas (11717) | about 10 years ago | (#10513904)

Other, even higher energy (non-nuclear) fuels include:

Metallic Hydrogen: 2 H(s) -> H2(g) 138 MJ/kg
Free-Radical Hydrogen: H + H -> H2 104 MJ/kg
Metastable Helium: He* -> He 480 MJ/kg
Ionic Hydrogen: H(+) + H(-) -> H2 835 MJ/kg


It occurs to me that if you're prepared to use magnetic confinement to store reagent ions, you can get an Isp as high as you like by using electrons and fully- (or just deeply-) ionized heavy atoms.

Hydrogen's ionization potential of 13.6 eV gives 1.3 GJ/kg on recombination.
Helium's ioniztion potentials of 24.5 and 54.4 eV give 1.9 GJ/kg.
Fully-ionized carbon gives 8.3 GJ/kg.

While magnetic confinement only allows low storage densities, with enough energy, this stops mattering. The only catch is that you have to have to be able to do something useful with the resulting photons (i.e. use them to heat an exhaust plasma, or in the worst case power an electric drive, though conversion efficiencies bite you there, as these photons are mostly soft x-rays).

For very heavy elements, with inner-shell electrons orbiting fast enough to be relativistic, you can get energy to mass ratios almost as good as fusion (one to two orders of magnitude worse).

Of course, ionized hydrogen has the virtue of being stable as crystal defects in frozen helium, unlike more aggressively ionized elements (though storing it like that gives a hefty Isp penalty).

Re:fuel, my ass! (1)

j_cavera (758777) | about 10 years ago | (#10514290)

Wow, didn't realize that the off-the-top-of-my-head figures and over-simplified explanation would generate so much traffic. To further explain some points:

Yes, magnetic confinement is very lossy and low-density. Except in the case of antimatter, its probably not worth the trouble. Though a prior poster had an interesting idea about magnetic confinement in space - kinda like an M2P2 (mini-magnetospheric plasma propulsion - google it for more info) thing.

As for my choice of numbers - with a bit of work, one can come up with fuels that are as high in energy density if not higher. My original numbers were pulled from: Space Propulsion Analysis and Design by R. Humble, et al; and Fusion Research by Dolan. Both are excellent references.

For more interesting information along the same lines, check: Advanced Energetics for Aeronautical Applications by D. Alexander. It's a NASA paper (NASA/CR-2003-212169) and should be available from the Langley Technical Reports Server [nasa.gov] .

Re:fuel, my ass! (1)

Christopher Thomas (11717) | about 10 years ago | (#10516430)

Yes, magnetic confinement is very lossy and low-density. Except in the case of antimatter, its probably not worth the trouble. Though a prior poster had an interesting idea about magnetic confinement in space - kinda like an M2P2 (mini-magnetospheric plasma propulsion

If it was a reply in this thread, that prior poster was me :).

Thinking about it, the best approach is probably to build a bent dipole (for preferential emission on one side), store both reagents in the same field, and vary the field strength to control reaction rate (which goes up with density, which is proportional to the square of the field strength). This lets you go from "takes a century to burn all the fuel" to "takes a week to burn all the fuel" with a factor of 100 field strength change. When you're at high field strengths, the plasma's dense enough that charged reaction products have time to thermalize with the rest of the plasma, giving you a way to tap the energy (assuming it doesn't just fly away in photons).

The catch is that you have a lower limit to field strength imposed by the ambient solar wind plasma. Too low, and the solar wind deforms your field and ruins containment (though as you point out, for MMPP that can be a benefit).

As for being useful - you can get very close to fusion numbers for magnetic confinement, and with a cold plasma, you can store your material at far, far higher density. If fusion drives are worth it, why wouldn't this be?

As for my choice of numbers - with a bit of work, one can come up with fuels that are as high in energy density if not higher.

Any higher than about 20 eV ionization energy for the ions, and you can't keep the fuel stable in a pressurized helium crystal. This places a limit on what you can use as a fuel without having to resort to magnetic confinement schemes.

I'm not trying to belittle your choice of numbers - I'm just trying to extend them :).

Re:fuel, my ass! (1)

sexylicious (679192) | about 10 years ago | (#10530535)

Good points...

But when increasing the magnetic field strength or decreasing it, you'd run into problems with ions and electrons hopping field lines or effects such as Bremstrahlung radiation from changing the angular momentum as your ions and electrons orbit a field line of varying strength.

Re:fuel, my ass! (1)

Christopher Thomas (11717) | about 10 years ago | (#10530674)

But when increasing the magnetic field strength or decreasing it, you'd run into problems with ions and electrons hopping field lines or effects such as Bremstrahlung radiation from changing the angular momentum as your ions and electrons orbit a field line of varying strength.

This limits the number of burns you can do (due to limiting the number of field changes), but I don't anticipate this being a huge problem.

Drift within the field would occur from scattering no matter what, limiting the containment lifetime you can achieve. This places a design constraint on the field - time for reaction has to be less than time for escape, for any given ion. This turns out to be fairly easy to satisfy.

The big problem is that you only really want to heat up the plasma you'll be expelling from the field; the stuff you want to hold onto is most easily held when cold (and heating the plasma gives you density problems, inhibiting reaction). It'll probably turn out that a more complicated field geometry that involves pinching a small fraction of the plasma is best (unless you want to blow through all of the fuel in one burn).

Re. radiation, I'd worry more about synchrotron radiation than Bremsstrahlung. Bremstrahlung is only important when you're imposing a very strong acceleration on the charge (i.e. smacking it into a solid target).

This may not ever be a practical drive (or a competitive one, compared to electric), but it's definitely an _interesting_ one.

Re:fuel, my ass! (1)

sexylicious (679192) | about 10 years ago | (#10538302)

Re. radiation, I'd worry more about synchrotron radiation than Bremsstrahlung. Bremstrahlung is only important when you're imposing a very strong acceleration on the charge (i.e. smacking it into a solid target).

I thought that's what was implied with a change in the field strength? You're right though that synchroton radiation would be more important except when the accelerations approach instantaneous.

As for heating the reaction, couldn't you hold a core of hot plasma and flow the colder stuff around it? Or actually burn some of the colder stuff to maintain a tightly wound magnetic field (via the currents generated by the burned fuel)? A D-D reaction would work just fine there... of course you'd need some tritium to start it, but as long as you kept feeding dueterium into the thing, you'd sustain your reaction and be able to control the temperature better.
It seems to me that the geometry that you'd want for this would more closely resemble a spheromak than a tube. Unless you're talking about a pulsed FRC, that may do it, but the tearing of the field lines to get the FRC conditions would seem to be too energy intensive.

Your approach is definitely interesting. You may want to just consider singly ionized heavy atoms though. That way you can stay relatively cool, and not have to supply the energy needed to more highly ionize the heavy atoms.

Re:fuel, my ass! (1)

Christopher Thomas (11717) | about 10 years ago | (#10545776)

Re. radiation, I'd worry more about synchrotron radiation than Bremsstrahlung. Bremstrahlung is only important when you're imposing a very strong acceleration on the charge (i.e. smacking it into a solid target).

I thought that's what was implied with a change in the field strength?

The accelerations involved in any kind of macro-scale displacement or compression of the fuel are far too low for bremsstrahlung to be significant. The minimum threshold above which you generally worry about x-ray emission from devices is around 10 kV, according to the electrical safety codes I've seen (though this is admittedly a pretty arbitrary value). This corresponds to a particle going from hundreds of km per second to zero in less than a microsecond. This kind of thing happens when particle beams or high-energy plasmas interact with stationary matter, and pretty much nowhere else.

As for heating the reaction, couldn't you hold a core of hot plasma and flow the colder stuff around it? Or actually burn some of the colder stuff to maintain a tightly wound magnetic field (via the currents generated by the burned fuel)?

The problem is this: You want to heat the plasma you're using as exhaust (you actually want it to be self-heating), but you want any plasma being stored for later to stay _cold_. The hotter it is, the lower its storage density and the faster it drifts out of your containment fields.

Hot plasma doesn't help your containment field, either. When you heat plasma in a magnetic field, it _expands_ and takes some of your field lines with it. This makes containment in the hot plasma bubble worse.

So, we either have a simple field where we react all of the plasma at once and let containment fail, for one big burn, or we have a complex field that lets us keep the plasma we don't want to burn just yet well away from the stuff that we do.

A secondary problem is that this plasma is _bad_ at self-heating. Electron/ion recombination releases its energy as light (EUV up to x-rays). You need to turn this light into usable energy, either as heat or as electrical energy. Plasma is reasonably opaque to UV if it's dense enough, so you may get it thermalizing, but it'll be iffy. X rays have a low enough interaction cross-section that you pretty much have to just use them to heat a solid containment vessel and get power for an electric drive off the resulting heat gradient.

A D-D reaction would work just fine there... of course you'd need some tritium to start it, but as long as you kept feeding dueterium into the thing, you'd sustain your reaction and be able to control the temperature better.

Fusion is a completely different problem than the ion recombination drive. For one, D+D fusion gives you mostly charged byproducts, so you have no problems making the plasma self-heating. For another, the plasma is insanely hot, so density is far lower and magnetic field strength has to be quite high if you don't want drift to kill it. Lastly, to get the reaction rate to anything useful for propulsion requires fields strong enough that you need magical materials for your field coils, and they _still_ end up being heavy enough that you're restricted to very, very low accelerations (at least in "use the fusion products as a high-Isp exhaust jet" mode - an electric drive would trade Isp off against acceleration more reasonably).

So, apples and oranges.

It seems to me that the geometry that you'd want for this would more closely resemble a spheromak than a tube. Unless you're talking about a pulsed FRC, that may do it, but the tearing of the field lines to get the FRC conditions would seem to be too energy intensive.

I'm using what's pretty close to an ordinary dipole, so none of the above. More exotic field geometries are needed when you're going for long-term confinement of a very hot plasma (spheromak, tokamak, etc), or when you're trying to use switchback currents to do plasma heating (schemes that involve field line tearing). A drive that was trying to use electron/ion recombination as a power source isn't doing any of these things.

Your approach is definitely interesting. You may want to just consider singly ionized heavy atoms though.

The whole point of this exercise is that multiply-ionized heavy ions give you more energy per unit mass on recombination. Otherwise you'd just use singly-ionized hydrogen and nothing else. The idea is to tweak the energy/mass ratio to give you Isps that would otherwise be impossible without some form of nuclear propulsion, hopefully at higher thust than nuclear-electric allows.

That way you can stay relatively cool, and not have to supply the energy needed to more highly ionize the heavy atoms.

This is a non-issue, because it's done by your dirt-side (or LEO-side) fuel plant, not your spacecraft. The spacecraft accepts cold heavy element ion and electron plasmas as fuel before setting out.

Re:fuel, my ass! (2, Insightful)

jeif1k (809151) | about 10 years ago | (#10506811)

You're right that hydrogen needs to be generated. The way hydrogen solves the looming oil shortages is by using it for energy storage and transport: the use of hydrogen allows solar and wind energy to be generated where they can be generated efficiently and then safely shipped to where they are needed.

As a fuel? (0, Redundant)

dtfinch (661405) | about 10 years ago | (#10506010)

It takes energy to pack energy to release energy.

Re:As a fuel? (1)

Mark of THE CITY (97325) | about 10 years ago | (#10506261)

It would be like hydrogen, or water in a reservoir: an energy storage medium.

Hmm (3, Interesting)

Couldn'tCareLess (818316) | about 10 years ago | (#10506030)

"which leads to the possibility of using it as a non-polluting fuel or high-explosive."
I wonder which one will get funding...

Military, then commercial (1)

jgardn (539054) | about 10 years ago | (#10506677)

The military has always been on the cutting edge. The game in the military is to have as much energy at your fingertips in a stable condition that is easy to use.

This is what commercial applications want as well, but without nearly the need of concentrated energy and with higher safety tolerances. (IE, we don't want a nuclear reaction to go critical in commercial applications.)

Re:Hmm (1)

nartz (541661) | about 10 years ago | (#10511025)

"...using it as a non-polluting fuel or high-explosive..."

Its obvious! A Non-polluting high explosive, duh!

Re:Hmm (1)

Spy Hunter (317220) | about 10 years ago | (#10517293)

The military already has plenty of high explosive. On the other hand, they use lots of fuel and are just as interested in improving efficiency as the rest of us, if not more. I don't see any reason why the military would fund research into using this as an explosive over using it as a fuel. But don't let me spoil your conspiracy theories...

caseless ammunition (1, Interesting)

Anonymous Coward | about 10 years ago | (#10506033)

seems like it would be good for use in ammunition smoke and greeseless, compact,light, maby water resistant,
if they can get it to detonate only under specific conditions it seems like it would make good caseless ammunition charge

Drilling? (2, Interesting)

Paster Of Muppets (787158) | about 10 years ago | (#10506274)

How about using it as a tip for drilling? If so, you'd need to work out how much pressure it could sustain, as well as its hardness factor (on the Mohs Hardness Scale [galleries.com] ). If it would have explosive tendencies at high pressure, I suggest it not be used to drill for oil. However, it could replace natural diamond to drill for metals, provided it is "harder" than them. If it should explode while drilling for metals, this could be rather useful...

Re:Drilling? (0, Troll)

rts008 (812749) | about 10 years ago | (#10506732)

LOL! Homer Homeowner+ powerdrill+explosive drill bits=Darwin Award! Maybe even new "Reality Show" based on switching out everday items with this stuff and taping results. Banned from BattleBots competition to avoid WMD's in the arena!

lol - what a great idea! (1, Funny)

kendoka (473386) | about 10 years ago | (#10506331)

Buy your honey a nitrogen diamond encrusted wedding ring - when she leaves your ass and takes half your shit you can just blow the bitch up.

Re:lol - what a great idea! (2, Insightful)

Anonymous Coward | about 10 years ago | (#10506562)

Better yet, don't call her a "bitch" and then maybe she might not leave your ass and take half your shit!

Re:lol - what a great idea! (0)

Anonymous Coward | about 10 years ago | (#10508734)

You've obviously never been married. Probably a virgin, too.

Re:lol - what a great idea! (1)

rts008 (812749) | about 10 years ago | (#10506661)

" Buy your honey..." Where did you wander in here from? This is /., terrortory of CMOS (Celibate Monks Of Sarcasm), the only honey we TRULY know we buy in little bear shaped containers. BTW, laffed my *ss off! GOOD IDEA!

Fuel, huh? (1)

SLiK812 (518195) | about 10 years ago | (#10508544)

Kirk: Scotty... have you... gotten... the Diamond... Nitrogen... crystals, re... crystalized? Scotty: We've put them in Mr. Spock's boot-crack. He's giving it all he's got. Spock: Mmmmm. Pure energy.

Re:Fuel, huh? (0)

Anonymous Coward | about 10 years ago | (#10513612)

Now all we need is a beryllium sphere and we'll be all set for interstellar exploration!

Why is it diamond like? (2, Interesting)

manganese4 (726568) | about 10 years ago | (#10509648)

From the pictures each nitrogen unit cell appears planar and the polymer appears in sheets, much more like graphite than diamond.

Ferris Bueler? (2, Funny)

sheapshearer (746106) | about 10 years ago | (#10509876)

accomplished by means of a crushing force From whose ass did this new harder-than-diamond material drop?

Hydronium? Nitronium? Protonium? (0)

Anonymous Coward | about 10 years ago | (#10513585)

Mmmmmm. Now that we have these I can get to work on building my planet killer that eats solar systems for fuel.

Aha! I see you shiver in anticipation!

Fools!

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