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[Orb]

I got to stop making posts at midnight.

Yah, you guys are right. Though I'm amazed I failed twice in such a short post.

[Virex]

I'm not sure how that follows, since the antimatter will liberate twice as much energy as is stored in its mass upon contact with any matter anyway, given that the matter it contacts will also be annihilating.

Correct.  The only inefficiencies would be whatever heat/induction/etc... the lasers and equipment used in the antimatter creation process causes.  Someone posted above that uranium is perfectly good for weapons.  That's certainly true, but I'm fairly confident in saying that there's nothing known to physics with greater energy density than antimatter.

There most certainly is. It's the laser beam/particle accelerator beam that was used to generate the antimatter in the first place.

Honestly, if you are going to make anti-matter in this method, its 50% efficiency, since half of it is matter, after all, If you are using twice as much energy into making a bomb than it will release, you are better off with a deathray or something.

A death ray is a point weapon.  An antimatter bomb is an area weapon.  Energy comparisons are meaningless as they have different uses.

A high power death ray will actually cause the surface of the target it strikes to evaporate explosively, so at the very least it'll cause a small-scale explosion (which is a problem for lasers since the debris and gas clouds caused by this explosion obscure the beam path, so laser weapons need to "scan" over their target to keep on adding more energy)

As I understand it now, the energy of the electron/positron together will contain whatever energy is leeched from the laser. Correct me if I'm wrong here. That means that what inefficiency there is will be caused by the focusing and recycling mechanism and any other outside apparatus, in addition to heat loss from whatever electricity is needed, inefficiency in producing the energy for the laser, and whatever material requirements there are.

I don't doubt that's simplifying things. But if you consider the massive amounts of energy we put into mining coal, oil, uranium, etc (including shipping, fuel and manpower for extraction equipment, sorting, refinement, and facilities operation) it could be up there with flywheels in vacuum in terms of efficient energy storage if we can make the laser and confinement devices cheap enough and efficient enough to operate. And it would be a fantastic financial resource for space-based facilities - just construct a huge solar collector, use the energy to create antimatter, use a lot less energy than what would be required in full gravity to make magnetic containment for it, and sell what you don't need.

Considering the energy that would need to be used to form a matter-antimatter pair, I wouldn't be surprised if you're losing 90% of your energy in cooling down the particles to a sensible level. Add to that the fact that a laser in itself only has an efficiency of 10% tops and that electron beams are worse and the energy needed to extract the antimatter (which would probably take a massive electrical field to suck the positrons one way and the electrons the other way), you're looking at a hefty cost per particle pair. Even then, most antimatter will be annihilated before you can catch it because anything created in the core of the reaction area will react with whatever is created at the edges. This effect can be limited by limiting the amount of pairs split per second, but then you'd need to wait till my Attari cracks the Assange code till you've got enough antimatter to see under an electron microscope.


Honestly, if you're going for energy storage, I can't see this beating SMES, which also takes considerable energy to maintain the energy storage, but has a far higher efficiency when it comes to loading and unloading the storage.

[Eagleon]

Considering the energy that would need to be used to form a matter-antimatter pair, I wouldn't be surprised if you're losing 90% of your energy in cooling down the particles to a sensible level. Add to that the fact that a laser in itself only has an efficiency of 10% tops and that electron beams are worse and the energy needed to extract the antimatter (which would probably take a massive electrical field to suck the positrons one way and the electrons the other way), you're looking at a hefty cost per particle pair. Even then, most antimatter will be annihilated before you can catch it because anything created in the core of the reaction area will react with whatever is created at the edges. This effect can be limited by limiting the amount of pairs split per second, but then you'd need to wait till my Attari cracks the Assange code till you've got enough antimatter to see under an electron microscope.


Honestly, if you're going for energy storage, I can't see this beating SMES, which also takes considerable energy to maintain the energy storage, but has a far higher efficiency when it comes to loading and unloading the storage.

You're probably right. I didn't realize lasers were so inefficient. For rocket fuel, though, nothing would beat antimatter in terms of mass requirements. Like I said, it might be something for when we can autonomously create large solar arrays in space, not for energy production for cities (it would be a lot cheaper just to point the laser from such a collector at Earth and harvest the heat than to ship antimatter bubbles in reasonable safety), but for interstellar vehicles that can't afford to carry along a nuclear reactor or solar collectors. It wouldn't be cheap, but time might be the more important resource. Of course, all of this would be solved neatly if we had cheap superconductors, but barring that...

As far as storage goes, in an isolated environment, wouldn't it be relatively cheap to keep a cloud of positrons centered in a relatively large surrounding magnetic bottle? Contending with interference from other magnetic fields is half of the battle, as I understand it. Or do I have things completely wrong? Sorry, this is just sparking some ideas for a book and I'm looking to see if it's feasible as I have it imagined.

[Virex]

As far as storage goes, in an isolated environment, wouldn't it be relatively cheap to keep a cloud of positrons centered in a relatively large surrounding magnetic bottle? Contending with interference from other magnetic fields is half of the battle, as I understand it. Or do I have things completely wrong? Sorry, this is just sparking some ideas for a book and I'm looking to see if it's feasible as I have it imagined.

see the last part of the paragraph. Storing the stuff is harder then you may think because a pure positron plasma is quite chaotic. (another interesting detail from that article is that the current efficiency of generating antimatter is estimated to be 10^-10, and that 50% of the energy released in a matter-antimatter reaction is lost in the form of neutrino's, which are notoriously hard to catch)

[Graebeard]

Honestly, if you're going for energy storage, I can't see this beating SMES, which also takes considerable energy to maintain the energy storage, but has a far higher efficiency when it comes to loading and unloading the storage.

Well, SMES is very efficient as far as energy storage and release goes, but it has nowhere near the energy density of antimatter.

For example, the combustion of one TNT molecule produces about 212 electron volts by my math.  The fission of a uranium atom produces about 200 MeV.  The annihilation of one atom of anti-hydrogen with one atom of hydrogen produces 1,877 MeV.  Protons and electrons are pretty common, so we can ignore that half of the reaction mass for storage purposes.  That means anti-hydrogen, gram for gram, has an effective energy density 2,205 times higher than fissionable uranium.  Now, I don't know exactly what the energy density of SMES is, but I don't think it has anything on antimatter. 

Also, this kind of stuff would be really, really handy if the mass of your energy source was important (like on a starship) or if you needed to blow up something really big, like a planet.  And while storing positrons might be tough because of the charge problem, anti-hydrogen has zero charge.  Also, it can be stored as a metal with sufficient (read: insanely high) pressure.  If you could somehow do that with magnetic fields (BTW, how do they work?) then transportation and storage is easy peasy.

Of course, all this is kibble compared to what anti-neutronium (density on the order of 10^14 higher than liquid helium) could do damage-wise.  I don't even want to think about that.

[Virex]

Honestly, if you're going for energy storage, I can't see this beating SMES, which also takes considerable energy to maintain the energy storage, but has a far higher efficiency when it comes to loading and unloading the storage.

Well, SMES is very efficient as far as energy storage and release goes, but it has nowhere near the energy density of antimatter.

For example, the combustion of one TNT molecule produces about 212 electron volts by my math.  The fission of a uranium atom produces about 200 MeV.  The annihilation of one atom of anti-hydrogen with one atom of hydrogen produces 1,877 MeV.  Protons and electrons are pretty common, so we can ignore that half of the reaction mass for storage purposes.  That means anti-hydrogen, gram for gram, has an effective energy density 2,205 times higher than fissionable uranium.  Now, I don't know exactly what the energy density of SMES is, but I don't think it has anything on antimatter.  

It doesn't, but it does have a storage efficiency of 95% as opposed to 10^-8% for positrons (note that anti-protons and as a result anti-hydrogen atoms are several orders of magnitude harder to make still).

[Graebeard]

For now, grasshopper, for now.

[Il Palazzo]

I don't think using antimatter as a fuel for spacetravel(or any civilian use) would be feasible - I'm not going to make wild guesses here about the size and weight of the containment facility for antimatter fuel, which could easily prove to outweight(literally) a regular nuclear reactor+fuel - but simply due to the difficulty of creating a fail-safe mechanism for an antimatter engine.
With good engineering, your nuclear fission reactor will just shutdown after failure. Same with the fusion ones. If the antimatter containment fails, the whole ship blows up immediately.

[Graebeard]

This SMBC comic is amazingly on point:

[Zrk2]

I love !!science!!

Can't wait for physics next semester so some of this makes sense because I currently only have grade 10 academic science and basic comprehension of physics and chemistry from various articles and an interest in learning.

[Tellemurius]

im still waiting for those liquid beta batteries.

[Virex]

Aren't beta-batteries restricted to military and spaceflight applications?