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Cosmic ray induced nuclear fusion

  1. Sep 15, 2012 #1
    Has anybody thought of it before?
    I mean even if it were energetically expensive to harness it it might actually create more than it takes since the energy source is raining down from the heavens anyway.
    Such a power plant would have to be placed at a high altitude though because most cosmic rays hit the atmosphere and are no longer in proton form before they reach near the surface.
    Perhaps even looking into using secondary cosmic rays (often muons) to facilitate muon-catalyzed fusion might be useful?
    I wonder... is it possible that the energy surplus from the original cold fusion experiment was due to a stray cosmic ray that hit the protons in the palladium hydride?
    And perhaps the crystal structure of the hydrogen made for a short-lived fusion chain reaction?
    What if the palladium hydride were supercooled? How would a hot proton bashing into it work then?
    Sorry for my ignorance... I want to learn here, see. It's so frustrating having so many ideas and not enough knowledge to know how to put them in action...
     
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  3. Sep 15, 2012 #2

    bcrowell

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    The flux of energy from visible light is a gazillion times higher than the flux from cosmic rays. If it wasn't, then astronauts would be killed in a fraction of a second by cosmic rays.

    No, it's not possible, because there was no such energy surplus; it's been amply documented that Pons and Fleischman were simply wrong.
     
  4. Sep 15, 2012 #3
    Regardless of flux, it is cosmic ray protons, not visible light, that have the energy to make contact with another proton and thus initiate fusion. The problem is getting enough of them to hit at once...
     
  5. Sep 15, 2012 #4

    bcrowell

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    Fusion isn't a chain reaction like fission. Initiating it doesn't do you any good unless you can maintain the temperature and pressure needed to sustain fusion.
     
  6. Sep 15, 2012 #5

    Drakkith

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    If you know a way of harnessing every high energy proton hitting the Earth at the same time, feel free to say so. I see nothing short of a complete spherical covering over the Earth that could do this.
     
  7. Sep 15, 2012 #6
    A satellite might work well, to get closer to the sun where the flux is greater... but well if energy input weren't an issue, one could probably substitute heavier elements to fuse and still get an energy surplus. Which ones might produce byproducts with enough energy to instigate a chain reaction?
    Also, would nuclear interactions be different in anyway if one of the materials was supercooled? Would that affect the byproducts, etc.?
     
  8. Sep 15, 2012 #7

    Drakkith

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    A couple of issues:

    1. A satellite away from Earth does us no good even if it could produce a net surplus of power.
    2. Fusion doesn't produce a chain reaction. At all. A typical nucleus in a reactor must collide hundreds if not thousands of times before it actually fuses, and this is with the best of fuels.
    3. Cooling one material would make no difference. It has no affect on the byproducts, as those are solely a result of the fuel type chosen.
    4. Heavier fuels are much harder to get to fuse and release less energy.
     
  9. Sep 15, 2012 #8
    But fission products only have to collide once right? As long as, say, if each nucleus that splits produces two high enough energy products to fuse, that at least half of them hit another nucleus to make it split (if more than half it would be supercritical right?)
    Cosmic rays must be hot enough to hit other elements, judging by the effects of spallation. All elements up to iron release more energy than they absorb when they are created, right? Hydrogen makes the most energy of course, but the energy required to contain it is greater than the energy it produces, so if a heavier element were easier to contain it might be worth the reduction in energy produced.
    I would like to know more about supercooled materials... superfluid helium, for example, has no friction, but it can absorb energy via other methods? If one were to bombard superfluid helium with high energy particles, would they just pass through unless they were the right energy level or do supercooling effects vanish at the nuclear level?
    So, say, were a helium molecule to be hit in the nucleus and suddenly become hot and release heat, that wouldn't affect the other superfluid molecules would it unless it hit them in the nucleus?
    And well if a satellite collected energy it could bring it back if it converted it to a battery, but in order to be worthwhile that battery had better have enough energy to power the world for a decade or so and I don't know of any way to store energy in such a quantity...
     
  10. Sep 15, 2012 #9

    Drakkith

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    That's semi-correct. A sustainable chain reaction requires that NEUTRONS be ejected from each decay. Neutrons are not electrically charged, so they don't get repelled by nuclei. This allows them to get very close and bind via the strong force. Having an extra neutron plus the extra energy from it's velocity is too much for the nucleus to handle and it ends up splitting and shooting more neutrons out that do the same thing.

    The other products of the decay do nothing to help the reaction. They simply carry energy away as kinetic energy, which ultimately ends up as heat, which is used to generate electricity in reactors.

    Heavy elements are not easier to contain. At least not much easier, if at all. However the real issue is that it is REALLY REALLY hard to get heavier elements to fuse. A proposed fuel of hydrogen-boron for aneutronic fusion (fusion without large amounts of neutrons being produced) is over 10 times harder than tritum-deuterium fusion, and releases less energy.

    First, single particles cannot have heat. Heat is a statistical measure of the average kinetic energy of a collection of particles. Generally trillions upon trillions in even a drop of water. Molecules might be able to be considered to have heat, as they can be made up of many atoms, but we usually use heat to describe large amounts of particles.

    Now, my knowledge on superfluids is not great, so I cannot say with certainty what would happen, I believe that the fluid would very quickly heat up as it absorbed high energy particles and become a normal fluid. Whether fusion can happen at that temperature I am unsure, as the atoms are all connected with each other since they act like bosons and all fall into the same energy state. Interacting with one would mean interacting with them all, so I don't know.

    Yep. And with current technology, or even near-future technology, such a battery would...heck, I don't think we have a word to describe how big it would be. Enormous, gigantic, astronomical in size, etc. It is completely unfeasible.

    The real kicker in all this is that cosmic ray induced nuclear fusion is simply not going to happen in any appreciable amount to be worth it. If you are going to fly a satellite close to the Sun you might as well throw some solar panels on it instead, it would be simpler, easier, and we know it works. You will have more cosmic rays impacting the rest of the satellite and causing damage than actually doing you any good.

    Also, is the Sun the source of high energy cosmic rays? I didn't think so, but I really don't know.
     
  11. Sep 15, 2012 #10
    Even the relatively weak cosmic rays have enough energy to fuse, if I am correct. But the sun isn't the source of the highest energy cosmic rays, that would be the outer reaches of the universe.
    If superfluid helium worked that way, that would be fantastic! ...that is, provided one could handle all that energy without it blowing up...
    What do you know about quantum entanglement? That might be a way to transfer energy over long distances and even maybe bypass the potential barrier?
     
  12. Sep 15, 2012 #11

    Drakkith

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    Perhaps you could provide details if you've already looked into it?

    What do you mean? If it worked which way? Why would it blow up?

    Not a chance. Entanglement doesn't work that way at all.
     
  13. Sep 15, 2012 #12
    They still aren't sure how the "oh my God" particles (the ultra high energy cosmic rays) came into being. There are theories of supernovae, the entire universe/galaxy working like a giant particle accelerator, etc.

    So if all of the superfluid helium atoms behaved as one unit, that means if one of them gets hit with enough energy to release energy, they all would? Or would it have to be a particle with enough energy to fuse all of them individually? Now suppose they were all to fuse at once, how would that energy be contained?

    And how exactly does entanglement work?

    I know also of the tunneling effect, say you know the "forbidden zone" that a particle cannot exist in but there is an equation that shows that its probability distribution lies partially on the other side of the barrier. So even if two particles don't have enough energy to fuse they can SOMETIMES (very rarely I'll bet) tunnel through the potential barrier and meet each other to fuse right?
     
  14. Sep 15, 2012 #13

    Drakkith

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    None of that would happen. In a superfluid the atoms all sit in the same state. If you spin liquid helium around and cool it until it goes into the superfluid phase it continues spinning forever! (The actual experiment was stopped after an hour or so, and no reduction in the motion was observed) It does this because you would need to apply enough energy to disrupt the entire fluid, not just one atom. Since friction doesn't provide enough energy each time an atom would be disrupted, the fluid experiences no friction.

    This does NOT mean that they can fuse all at once, nor that they could all release energy if one gets struck. This is physically impossible, as you need each atom to fuse with something! And we can't "suppose that they all fuse at once". Again, this is not going to happen. I don't think I can explain it very well, so it may be confusing.

    That topic is best discussed in the Quantum Physics forum. There are plenty of threads already if you do a search for them using the search function. You can also find lots of info online.

    However, I will say that no information and no energy can be transferred. There is no transfer of anything. It's just measuring the state that particles are in.

    Of course. The uncertainty principle tells us this. The higher the energy, the more probable it is that tunneling will happen. This is also why nuclear decay happens in heavy nuclei like uranium.
     
  15. Sep 15, 2012 #14
    Friction is the large-scale interpretation of the small-scale phenomenon of electron shells brushing by other electron shells and transferring energy in chaotic ways, correct? In superfluid helium it appears that that doesn't happen to the helium shells, and there is no reason for it to since helium shells are full and neither wanting to give nor receive other electrons, tug/push at them, etc. which raises the question why hotter helium has friction... also isn't the temperature at which helium-3 becomes a superfluid different than when helium-4 becomes a superfluid? Which means the phenomenon has some relation to mass or the nucleus...
    Suppose the superfluid helium were spinning at a very high angular velocity (the values it can assume are quantized right?) wait... how can they get it to spin, wouldn't it just slide against the walls of the container? Anyway, if it spins fast enough the particles would have the same average kinetic energy as a very very VERY hot sample of helium in the sun, so by the definition of temperature it would be VERY high temperature. Except it does not exhibit the entropic disorder characteristic of the hot helium in the sun...

    But suppose you were to spin two canisters of helium in opposite directions, connect them with a shut valve, and open the valve just as the helium reached a high enough angular velocity...

    As for entanglement, well, it allows you to know what state the particles are in without directly interfering with the right? Because if you could create a computerized machine that measures the states of the entangled particles and fire a laser when all or most of them are measured to be in a certain state, supposing some kind of inertial confinement system where it is optimal for all or most of the particles to be in a certain state at the time the laser is fired?
     
  16. Sep 16, 2012 #15

    Drakkith

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    The full shells have little to do with it. As bosons, helium atoms in a superfluid state "share" everything. I don't think I can describe it well. If you want to stop the motion of one you have to provide enough energy to modify the motion of the entire fluid. (Or a large portion of it. I'm not 100% sure) For helium-3 this is different, it is more of a result of the BCS theory.

    I think they spin it while they are cooling it down. Also, temperature doesn't work like that. You have to look at the average motion of the particles with respect to themselves. If you just rotate them around the same way we could just shift our frame to the rotating one and there would be no motion.

    I don't understand anything you said here.

    Unfortunately we have gotten fairly far off topic, so I think it's best that you take your questions to the appropriate subforums.
     
  17. Sep 16, 2012 #16
    BAAAACK on topic...

    Ah, I get it! You only know about magnetic confinement fusion, you don't understand inertial confinement fusion at all... in that case a chain reaction does occur. It involves firing a laser at a small pellet of fuel in order to cause it to implode and release energy. Now if cosmic rays could be focused onto such a target, it would eliminate the requirement for a laser and all the energy it costs... that might be accomplished to some degree by building an enormous magnetic funnel at a high altitude that would bend the cosmic rays inwards to create a fine, pressure-packed particle stream. That would not eliminate the other problems associated with inertial confinement fusion however, such as efficiently collecting the energy and all of the neutrons produced...
     
  18. Sep 16, 2012 #17

    Drakkith

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    No I understand inertial confinement, I just didn't get what you said at the time. Now it makes sense. All I can say is that learning more about entanglement and quantum mechanics would tell you that your earlier idea isn't possible. Study up!

    As for bending cosmic rays, your machine would be unfeasibly large, if its even possible. By the way, this thread probably borders on overly speculative, as inventing machines isn't what PF is for.
     
  19. Sep 16, 2012 #18

    mfb

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    A rough estimate based on this diagram and WolframAlpha gives O(1µW/m^2) of cosmic rays. Give or take one order of magnitude - light from the sun hits earth with 1kW/m^2 and is way easier to focus.

    As comparison: NIF uses 500 terawatts, this corresponds to the solar radiation in 500,000km^2 - about the area of france or 5% of the US. With cosmic rays, you would need 1 million times this area, or a disk with a radius similar to the moon orbit.
     
  20. Sep 16, 2012 #19
    So that's... a gigaelectronvolt per square meter per second? Assuming that energy isn't spread too thin among too many particles, it is more than enough to break the potential barrier (about .1Mev for deuterium-tritium, what would it be for proton-proton?) Supposing the flux of a square meter were to pass through a magnetic funnel to bend them to change the flux to a Gev per square centimeter per second... what height and magnetic strength would accomplish this? I'm imagining very tall with lots and lots of neodymium magnets should we stick to permanent magnets... also some figures on the expected nuclear cross section would be helpful...
     
  21. Sep 16, 2012 #20

    mfb

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    Proton-proton has a bad cross-section.
    Cosmic particles come from everywhere, you cannot focus them further with magnets. You can throw away 99% of the particles and focus the remaining 1% to a small spot, but then you cannot add more particles from elsewhere to the focus. Well... at least in space. On earth, you might gain a factor of 2 as you naturally do not get particles from below. Still not enough to be interesting.
     
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