The following is a third draft of a formative hypothesis for excess energy release in one category of LENR involving nickel as the active host; and in particular the Arata-Zhang results and numerous replications.
Thanks to Robin's input, I have dropped the suggestion that the nickel beta decay can then stimulate actual deuterium fusion, since a putative route to that end-result is not evident as of now. Arata demonstrated, in a remarkable low-powered (unpowered) experiment, a stronger excess heat effect in nickel than in palladium; but an alloy of nickel with about 15% Pd seems to be optimum. The key to his success is probably related to nanostructure - but it highlights the fact that nickel is likely to be the better choice for the host matrix in any kind of LENR, especially when alloyed, and for the reasons independent of geometry, to be outlined below. The logic of that observation is that an essentially unpowered experiment, which has been reproduced by at least six groups to date (two yet to be published) must imply that when power is added, the gain will be multiplied. This obvious "next step" is underway in a few labs. The further hope is that a combination of nanostructure, isotope enrichment, Casimir cavity enhancement and outside energy input can be anticipated to push the results of a hybrid reactor much closer to the level of what will needed for the long-awaited commercial application, even if that first product only involves space heating. Some background material may be found in Scientific American, June, 1995, pp 90-95 in an article by Austin & Bertsch, entitled "Halo Nuclei." The sub-title is important: "Nuclei having excess neutrons or protons teeter on the edges of nuclear stability, known as "drip lines." A modality for converting the metastable halo nuclei to unstable isotopes may involve a low energy spallation-type reaction for "neutron stripping", possibly a low energy variant of the Oppenheimer-Phillips (O-P) effect. The first relevant fact is that over two-thirds of natural nickel is the isotope 58Ni, which has very high nuclear stability - but there is also a ~1% isotope 64Ni which is 6 a.m.u. or ~11% heavier, and which has been studied in cosmology and medicine. From there on, "facts" fade and the explanation offered is to a large part contingent on how well it explains experimental results. There is a boundary line that shows up on a chart of the periodic table, suggesting the stability of isotopes which vary far from the trace are going to be marginally unstable, and it is called the drip line. The value of the neutron drip line, for an excess ratio in nickel is not determined, but an excess of over 10% (over the most stable isotope) tends to point to some metastability. A "halo" is descriptive of nuclei above the drip line, which will express a much apparent radius than normal, for reasons which are not well understood. These nuclei will have a transient neutrons that can be located in a well beyond the normal radius, and which would appear to exhibit a halo, if they could be seen. Isotopes on the edge of the drip line may be metastable only when they are subject to time distortion in a Casimir cavity - assuming that Fran Roarty's hypothesis is correct. A version of neutron stripping (low energy spallation) which is appropriate for this scenario begins with with a spatially polarized deuteron, which has been taken into the nickel atom's "electron cloud". In order to strip an excess neutron from "heavy nickel" the polarized deuteron will need to be accelerated towards the halo nucleus with its neutral end pointed towards that nucleus to provide some measure of charge shielding . There is a QM probability of neutrons in halo atoms getting near the limit of strong-force influence, especially under the stress of a charge incursion. A deuteron incursion into the "Coulomb well" of a nickel halo atom would likely suffice to cause the level of stress leading to a free neutron or a free proton, and with a resultant unstable nucleus. The second possible route to disrupting the stability of 64Ni could be a low energy version of the normal O-P effect, where the deuteron enters the halo cloud, is accelerated by a sling-shot effect, and a proton is ejected. The former leads to a decay to copper and the later to cobalt. Both of these elements have been seen in transmutation products from LENR electrodes in nickel based LENR, after extended runs. The Ni-64 isotope spans unstable 63Ni in the range of stability. 63Ni is a beta emitter with a fairly short half-life and seems to be the most likely "culprit". If 'heavy nickel' loses a neutron by any number of routes from the 'expanded halo' due to charge incursion or a Casimir effect, it then goes to 63Ni. If it decays in one step, it will give up a fast ~67 keV beta electron and no gamma; following which it will transmute into to the most abundant isotope of copper 63Cu. This would elegantly explain a number of experimental findings. For better understanding the prior range of nickel experiments of the past 19 years, it is important to keep in mind these facts: that nearly one percent of natural nickel is 10% heavier than the majority isotope, that nickel is a facile deuteron conductor, that there is little detectable radioactivity during the extended runs, and that the effects are difficult to reproduce. The net result of this overlap is that the heavy nickel isotope if identified as the previously unrecognized "fuel" for the many claims of excess heat or LENR in nickel, makes sense. Of course, all of this is a great stretch of the imagination due to its novelty, and admittedly is a house of cards - with the main redeeming virtue that it explains more experimental details with fewer holes than alternative theories - which are equally stretched. Experiment rules ! but it never hurts to have the best working hypothesis handy. An implication of this hypothesis is the "mixed results" of the past: which becomes mundane as the source of the nickel can be important. LENR has been notoriously hard to reproduce with both palladium and nickel, up until the Arata nickel alloy was developed. That can now be seen to be (at least in part) a function of a natural variation in the isotope ratio of 64Ni, which discrepancy has been noticed in cosmology: a known overabundance of heavy nickel in meteorites. Some nickel mines, such as famous Sudbury mines in Canada, exploit the impact sites of an ancient meteorite impact. I cannot find a reference to Canadian nickel being higher in 64Ni however - and it may not be. If there is no difference in the isotope ratio, based on origin, then this detail of the hypothesis may not hold up. But the point is that there could be variation in natural nickel isotope ratios of fabricated electrodes, based on the origin of the metal. However, the reliability of the Arata replications indicates that a nanopowder alloy with zirconia and a small amount of palladium can solve the problems related lower isotopic ratio, if it exists. What is unknown at this juncture is: can the Arata-type results can be enhanced and taken to a much higher level with an actual enrichment of heavy nickel ? This could be answered within a few months. The energy released from the decay of 63Ni is surprisingly low for a nuclear reaction, and the ash leaves little tell-tale trace of radiation but there is transmutation, yet since copper is so ubiquitous one needs to look for it where it should not be found. This moderate energy release can explain why the indicia of the reaction are hard to spot. On the positive side, it means that nickel has several hundred times more energy per atom than is found in chemical reactions - since about one percent of it will have about 67 KeV of mass-energy. The average is over 600 eV per atom, and even if only a fraction of it can be easily used in a given time frame, this can serve to explain mysteries which other LENR theories fail to explain. The best part of the hypotheses is that it is falsifiable. If a side by side experiment involving nickel cathodes - one of which is enriched in 64Ni and the other is normal or depleted - serves to demonstrate a significant variation in energy release, favoring the heavy nickel, then that is a prima facie case. Another test would be to look for copper or cobalt as the transmutation product. But the complete hypothesis goes beyond the fact that a fraction of the net energy release is a result of non-fusion beta decay. The complete hypothesis should envision two steps - a driver, which is beta decay, and then subsequent fusion which is of a yet unknown method which may benefit from the first step: beta decay. In an earlier version of this hypothesis, it was suggested that a (substitute) muon catalyzed fusion, or fast electron catalyzed, depending on which aspect one chooses to emphasize, could be possible. That seems less likely after consideration; and the secondary reaction part of this hypothesis is being dropped for now. Instead of "denying fusion" then - this beta-decay hypothesis explains one source of moderately high energy which is available for the ultimate fusion of deuterium, in a second stage but cannot specify how that occurs. It is energy which would not be expected to be detectable but the transmutation products are identifiable and easily detectable, so falsifiability is guaranteed. The main novelty of this hypothesis is that it focuses exclusively on a specific isotope - "heavy nickel" (64Ni) - with the suggestion that the metastability of the extra neutrons in this isotope can be exploited in a number of ways, such as in a Casimir cavity via relativistic and QM effects like time distortion. Jones
