Bussard Collectors
- Thread starter thesovereignman
- Start date
Technically, because deuterium has less mass and therefore needs more pressure and temperature to fuse. Not sure why this would be a problem with modern treknology, tho.
I believe we've just succeeded in changing the laws of physics. Hydrogen has one proton and one electron. Deuterium has one proton, one neutron, and one electron. It has MORE mass than hydrogen. That makes it easier to fuse, for us poor 21st century humans. The sun seems to fuse simple hydrogen quite nicely.
Lets not confuse deuterium, which might be needed for the fusion reactors, for hydrogen, which should be easier to use for the antimatter ("warp core") reactor. There's no clear reason for a ship's matter to be anything other than a proton, and the antimatter to be anything other than an antiproton. Adding the electron would make the destruction more complicated - you would need a positron to make anti-hydrogen. Adding the neutron ditto - you need an anti-neutron to make anti-deuterium. Why bother?
Hydrogen is widely plentiful and would make a perfectly good matter source for a matter-antimatter reaction. Its easy to strip off the electron to get the proton for the reaction. The use of the word deuterium is just interesting writing, not something that technically makes much sense. Its rarer and therefore harder to collect.
(of course, as said above, it would be easier to fuse. you might collect both and use the hydrogen for the warp core and the deuterium, which is a very small percentage, for fusion).
This is established science today. We make protons and anti-protons today and collide them today. Adding 1/1700th more mass, which is what the electron brings, isn't enough energy to matter. Adding the neutron... just complicates things. Why have them buzzing around when you can achieve a perfectly good proton-antiproton reaction?
Deuterium isn't easier to fuse just because it has more mass. Iron has more mass and it is ridiculously hard to fuse, to the point that the reaction is actually endothermic, which is why trans-iron elements tend to only be made in supernovae. Heck, even helium-3, for all its advantages in that its fusion reaction is aneutronic--unlike the destructive neutron flux-producing deuterium and deuterium-tritium reactions--has a much higher ignition point than tritium, despite being actually a little lighter.
It's easier to fuse because the neutron doesn't contribute to the Coulomb resistance that makes atoms hard to fuse. Also, and to a much lesser degree because of the limited range of the strong force, it does contribute to the strong interaction that makes fusion possible.
As pointed out above, none of this is helpful with an annihilation reaction. There is a negative Coulomb repulsion between a proton and antiproton--that is, they're electrically attracted. I'd suspect you still have to have good aim and reasonably high velocities to acheive high efficiencies, but your job's easier than it would be otherwise.
As for deuterons and antidueterons, I think you might add in a reaction cross-section problem that would totally undermine whatever rest-mass-added advantage in rest mass conversion you'd have over protium. The charged pion products from a p+/p- collision are problematic enough. I wonder what the reaction would actually look like with deuterons? I'm picturing extremely fast neutrons and antineutrons (or protons and antiprotons, as the case may be), blasted by decaying neutral pions, flying into and through the reaction chamber.
That said, to answer the question of why bothering to make heavier antimatter at all, I imagine economical containment would be greatly supported with the development of a containment system actually made of antimatter. I think it would be a lot easier to magnetically contain a antimatter high-temperature solid superconductor that's holding neutral, pressurized, gas- or liquid-phase hydrogen than using matter magnets to directly hold hydrogen (or "deuterium") that is simultaneously somehow both liquid and susceptible to magnetic fields (ionized?). Whatever the mechanics, it's clear that whatever the faults of Federation starship design, their antimatter pods are almost as extraordinarily resilient as their gravity generators.
It's easier to fuse because the neutron doesn't contribute to the Coulomb resistance that makes atoms hard to fuse. Also, and to a much lesser degree because of the limited range of the strong force, it does contribute to the strong interaction that makes fusion possible.
As pointed out above, none of this is helpful with an annihilation reaction. There is a negative Coulomb repulsion between a proton and antiproton--that is, they're electrically attracted. I'd suspect you still have to have good aim and reasonably high velocities to acheive high efficiencies, but your job's easier than it would be otherwise.
As for deuterons and antidueterons, I think you might add in a reaction cross-section problem that would totally undermine whatever rest-mass-added advantage in rest mass conversion you'd have over protium. The charged pion products from a p+/p- collision are problematic enough. I wonder what the reaction would actually look like with deuterons? I'm picturing extremely fast neutrons and antineutrons (or protons and antiprotons, as the case may be), blasted by decaying neutral pions, flying into and through the reaction chamber.
That said, to answer the question of why bothering to make heavier antimatter at all, I imagine economical containment would be greatly supported with the development of a containment system actually made of antimatter. I think it would be a lot easier to magnetically contain a antimatter high-temperature solid superconductor that's holding neutral, pressurized, gas- or liquid-phase hydrogen than using matter magnets to directly hold hydrogen (or "deuterium") that is simultaneously somehow both liquid and susceptible to magnetic fields (ionized?). Whatever the mechanics, it's clear that whatever the faults of Federation starship design, their antimatter pods are almost as extraordinarily resilient as their gravity generators.
That's the single best reason i've ever heard for using an element ("hydrogen") versus raw particles.
Not that I am disagreeing here, nor with any of the other possibilities, but it seems that everyone assumes that the hydrogen collected is purely for the use of energey generation (fusion reactor, M/AM reactor, etc.). Why can't it be for some other function?
Maybe it is used by the replicators to produce food. Maybe in holodecks to produce food or furniture (granted, IIRC, there is non-canonical evidence to suggest that forcefields provide all walls, furniture, and other surfaces, but again it is non-canonical).
Perehaps we need to look outside the engines for possible hydrogen uses.
^There's no need to collect hydrogen for life needs. It's not expended, only rearranged. The only thing any system needs once the original elements are there is energy and regulation. The Earth doesn't rely on influxes of hydrogen to sustain its biosphere--why would the far more tightly contained environment of a starship need to import it?
The only reason they'd ever need more hydrogen (and carbon, oxygen, nitrogen, etc.) is if they wanted to expand the system, i.e. with children.
In fairness, it's an adaptation of an idea I read on stardestroyer.net. I forget whose notion it was, but he liked the concept of an anti-iron ferromagnetic bottle. For a couple of reasons, I think a superconducting magnet might be better. First, as noted iron is very difficult to produce from raw hydrogen, which is all you're ever likely to get from pair production, so a solid anti-iron bottle is probably economically unworkable. Second, I'm not sure that an iron magnet would provide the necessary repulsion. Magnesium diboride is a newer high-temperature superconductor that at least satisfies the first problem: magnesium and boron are much easier to construct than iron (although it's true that boron tends to be skipped over during natural stellar fusion).
That said, a superconducting magnet has the disadvantage of needing to be cooled, MgB2 to less than 39K, to take advantage of its superconducting properties, and that might be much more of a problem than just floating an iron sphere. Fortunately, cryogenic fluids tend to be low in their atomic number as well, so if building the whole cooling system out of antimatter is necessary, it seems remotely plausible.
Unfortunately, I don't know nearly enough about magnets or superconductors to really speak authoritatively on how this would all be done. A lot of this could be totally wrong.
Finally, one problem that I haven't much considered is that an antimatter magnet will have opposite properties of a matter magnet. In a matter magnet, the magnetism of an object is determined by the pairing of electrons. In an antimatter magnet, positrons, which obviously have an opposite charge. So the only matter they'd repel would be positively charged, like it.
The only reason they'd ever need more hydrogen (and carbon, oxygen, nitrogen, etc.) is if they wanted to expand the system, i.e. with children.
Search4 said:
In fairness, it's an adaptation of an idea I read on stardestroyer.net. I forget whose notion it was, but he liked the concept of an anti-iron ferromagnetic bottle. For a couple of reasons, I think a superconducting magnet might be better. First, as noted iron is very difficult to produce from raw hydrogen, which is all you're ever likely to get from pair production, so a solid anti-iron bottle is probably economically unworkable. Second, I'm not sure that an iron magnet would provide the necessary repulsion. Magnesium diboride is a newer high-temperature superconductor that at least satisfies the first problem: magnesium and boron are much easier to construct than iron (although it's true that boron tends to be skipped over during natural stellar fusion).
That said, a superconducting magnet has the disadvantage of needing to be cooled, MgB2 to less than 39K, to take advantage of its superconducting properties, and that might be much more of a problem than just floating an iron sphere. Fortunately, cryogenic fluids tend to be low in their atomic number as well, so if building the whole cooling system out of antimatter is necessary, it seems remotely plausible.
Unfortunately, I don't know nearly enough about magnets or superconductors to really speak authoritatively on how this would all be done. A lot of this could be totally wrong.
Finally, one problem that I haven't much considered is that an antimatter magnet will have opposite properties of a matter magnet. In a matter magnet, the magnetism of an object is determined by the pairing of electrons. In an antimatter magnet, positrons, which obviously have an opposite charge. So the only matter they'd repel would be positively charged, like it.
It would seem to me that not everything in a holodeck is the creation of colored forcefields, if you walk into a holodeck room and there is food present, the computer that created that room, that scene, can't know in advance that you're not going to walk over to the table and take a bite out of something. All the food is real replicated food. Data's tobacco for his pipe is real too. The piece of paper that Data and Geordi walk off the holodeck with was solid real. Buildings, trees, people and animals would be projections.
Hydrogen vs deuterium. Hydrogen and anti-hydrogen for the warp reactor, deuterium for the impulse engines assuming that the impulse engines are fusion rockets. However if the impulse can make use of hydrogen too, so much the better.
The matter and antimatter in the warp reactor doesn't have to fuse, it comes together for annihilation, that's how the energy is released. And it could be a kilo of anti-feathers and a kilo of aluminum pepsi cans.
Much more efficient to use atom/antitatom combinations for annihilation reactions. Energywise the nuclei could be better than atoms, but harder to store for long periods of time, AFAIK.
Similar threads
