On Wed, Jan 23, 2013 at 10:04 PM, Chuck Sites <[email protected]> wrote:
The proton-proton chain reaction is initiated with a strong interaction > between two protons, that binds to form a diproton, the diproton then > decays via weak interaction (a W boson) into a deuteron + electron + > electron neutrino and 0.42 MeV of energy. > Wikipedia has a very good description of this processes: > The proton-proton chain does seem promising at first, especially when one takes into account some of the difficulties with the kind of activation that would occur if there were a lot of neutron-moderated reactions. But the proton-proton chain has its own difficulties. See [1], below, for an earlier discussion. Briefly, the diproton lasts for a vanishingly small amount of time before it breaks up. Only a very small fraction of diprotons go on to form deuterium; in the sun, this process is a limiting one that prevents it from rapidly burning through its fuel. In known cases, the rate of deuterium formation is small because the weak force requires that a very high energy barrier be surpassed before a proton will convert to a neutron. Widom and Larsen have other ideas on this particular point, and it is part of what makes their writings difficult for physicist types (of which I am not one) to get a handle on. See also the comments to this physics.SE question for more details [2]. I believe Ed Storms proposes an alternate form of weak-force moderated nuclear reaction, along the lines of a slow p-e-p reaction, and I would assume that similar difficulties must be addressed in this instance as well. Assuming the weak interaction really does provide a limiting barrier, any fusion-like reaction is presumably going to have to occur either through the action of deuterium or higher, on one hand, or through proton capture within a larger nucleus, on the other, unless a non-fusion reaction along the lines of what Jones or Mills describes is going on. Obviously there is also the matter of the Coulomb barrier, but I think we've gotten used to ignoring it for the sake of convenience. ;) Eric [1] http://www.mail-archive.com/[email protected]/msg67691.html [2] http://physics.stackexchange.com/questions/23640/what-interactions-would-take-place-between-a-free-proton-and-a-dipolariton
