Cold fusion

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Cold fusion, sometimes called low energy nuclear reactions (LENR) or condensed matter nuclear science, is a set of effects reported in controversial laboratory experiments at ordinary temperatures and pressures, which some researchers say are caused by nuclear reactions.

In 1989, Martin Fleischmann and Stanley Pons reported producing a tabletop nuclear fusion reaction at the University of Utah. In their press conferences and papers, they reported the observation of anomalous heating ("excess heat") of an electrolytic cell during electrolysis of heavy water using palladium (Pd) electrodes. Lacking an explanation for the source of such heat, they proposed the hypothesis that the heat came from nuclear fusion of deuterium (D). The report of their results raised hopes of a cheap and abundant source of energy.

Cold fusion gained a reputation as pathological science after other scientists failed to replicate the results. A review panel organized by the US Department of Energy (DOE) in 1989 did not find the evidence persuasive. Since then, other reports of anomalous heat production and anomalous Helium-4 production have been reported in peer-reviewed journals and have been discussed at scientific conferences. Most scientists have met these reports with skepticism. In 2004 the US DOE organized another review panel (US DOE 2004) which—like the one in 1989—did not recommend a focused federally-funded program for low energy nuclear reactions. The 2004 panel identified basic research areas that could be helpful in resolving some of the controversies in the field. It stated that the field would benefit from the peer-review processes associated with proposal submission to agencies and paper submission to archival academic journals.

Since 2004, two peer-reviewed literature reviews have concluded that cold fusion has been demonstrated by experiments that result in excess heat production and nuclear reaction products such as helium-4. The reviews state that although many explanations have been proposed, several of which do not use new physics, none is yet satisfactory.

Contents 1 History 1.1 Early work 1.2 Fleischmann-Pons announcement 1.3 Reaction to the announcement 1.4 1989 DOE panel 1.5 Further developments (1989-2004) 1.6 2004 DOE panel 1.7 Recent developments 2 Summary of evidence for cold fusion 2.1 Excess heat 2.2 Nuclear products 2.3 Nuclear transmutations 3 Criticism 3.1 Precision of calorimetry 3.2 Lack of reproducibility of excess heat 3.3 Missing nuclear products 3.4 Lack of theoretical explanations 4 Notes 5 References 6 Bibliography 7 Further reading

[edit] History

[edit] Early work

The special ability of palladium to absorb hydrogen was recognized as early as the nineteenth century by Thomas Graham.^[1] In the late nineteen-twenties, two German scientists, Friedrich Paneth and K. Peters, reported the transformation of hydrogen into helium by spontaneous nuclear catalysis when hydrogen was absorbed by finely divided palladium at room temperature.^[1] These authors later acknowledged that the helium they measured was due to background from the air.

In 1927, Swedish scientist J. Tandberg stated that he had fused hydrogen into helium in an electrolytic cell with palladium electrodes.^[1] On the basis of his work, he applied for a Swedish patent for "a method to produce helium and useful reaction energy". After deuterium was discovered in 1932, Tandberg continued his experiments with heavy water. Due to Paneth and Peters' retraction, Tandberg's patent application was eventually denied.^[1]

The term "cold fusion" was coined by Dr. Paul Palmer of Brigham Young University in 1986 in an investigation of "geo-fusion", or the possible existence of fusion in a planetary core.^[2]

[edit] Fleischmann-Pons announcement

Fleischmann said that he began investigating the possibility that chemical means could influence nuclear processes in the 1960s.^[3] He said that he explored whether collective effects, that would require quantum electrodynamics to calculate, might be more significant than the effects predicted by quantum mechanical calculations.^[4][5] He said that, by 1983, he had experimental evidence leading him to believe that condensed phase systems developed coherent structures up to 10^-7m in size.^[4] In 1984, Fleischmann and Pons began cold fusion experiments.^[6]

In their original set-up, Fleischmann and Pons used a Dewar flask (a double-walled vacuum flask) for the electrolysis, so that heat conduction would be minimal on the side and the bottom of the cell (only 5 % of the heat loss in this experiment). The cell flask was then submerged in a bath maintained at constant temperature to eliminate the effect of external heat sources. They used an open cell, thus allowing the gaseous deuterium and oxygen resulting from the electrolysis reaction to leave the cell, along with some heat. It was necessary to replenish the cell with heavy water at regular intervals. The authors said that, since the cell was tall and narrow, the bubbling action of the gas kept the electrolyte well mixed and of a uniform temperature. Special attention was paid to the purity of the palladium cathode and electrolyte to prevent the build-up of material on its surface, especially after long periods of operation.

The cell was also instrumented with a thermistor to measure the temperature of the electrolyte, and an electrical heater to generate pulses of heat and calibrate the heat loss due to the gas outlet. After calibration, it was possible to compute the heat generated by the reaction.^[7]

A constant current was applied to the cell continuously for many weeks, and heavy water was added as necessary. For most of the time, the power input to the cell was equal to the power that went out of the cell within measuring accuracy, and the cell temperature was stable at around 30 °C. But then, at some point (and in some of the experiments), the temperature rose suddenly to about 50 °C without changes in the input power, for durations of 2 days or more. The generated power was calculated to be about 20 times the input power during the power bursts. Eventually the power bursts in any one cell would no longer occur and the cell was turned off.

In 1988, Fleischmann and Pons applied to the United States Department of Energy for funding towards a larger series of experiments. Up to this point they had been funding their experiments using a small device built with $100,000 out-of-pocket.^[8] The grant proposal was turned over for peer review, and one of the reviewers was Steven E. Jones of Brigham Young University.^[8] Jones had worked on muon-catalyzed fusion for some time, and had written an article on the topic entitled "Cold nuclear fusion" that had been published in Scientific American in July 1987. Fleischmann and Pons and co-workers met with Jones and co-workers on occasion in Utah to share research and techniques. During this time, Fleischmann and Pons described their experiments as generating considerable "excess energy", in the sense that it could not be explained by chemical reactions alone.^[9] They felt that such a discovery could bear significant commercial value and would be entitled to patent protection. Jones, however, was measuring neutron flux, which was not of commercial interest.^[8] In order to avoid problems in the future, the teams appeared to agree to simultaneously publish their results, although their accounts of their March 6 meeting differ.^[10]

In mid-March, both research teams were ready to publish their findings, and Fleischmann and Jones had agreed to meet at an airport on March 24 to send their papers to Nature via FedEx.^[10] Fleischmann and Pons, however, broke their apparent agreement, submitting their paper to the Journal of Electroanalytical Chemistry on March 11, and disclosing their work via a press conference on March 23.^[8] Jones, upset, faxed in his paper to Nature after the press conference.^[10]

[edit] Reaction to the announcement

The press initially reported on the experiments widely, and due to the surmised beneficial commercial applications of the Utah experiments, "scores of laboratories in the United States and abroad" attempted to repeat the experiments.^[11] The announcement raised hopes of a cheap and abundant source of energy.^[12]

On April 10, 1989, Fleischmann and Pons, who later suggested pressure from patent attorneys, published a rushed "preliminary note" in the Journal of Electroanalytical Chemistry.^[7] This paper notably contained a gamma peak without its corresponding Compton edge, a discrepancy that triggered accusations of fraud.^[13][14][15] Their "preliminary note" was followed up a year later in July 1990, when a much longer paper, going into details of calorimetry but without any nuclear measurements, was published in the same journal.^[9]

Also occurring on April 10, a team at Texas A&M University published their results of excess heat, followed up by a team at the Georgia Institute of Technology who observed production of neutrons.^[16] Both results were widely reported on in the press, although both Texas A&M and the Georgia Institute of Technology withdrew their results for lack of evidence.^[16] For the next six weeks, additional competing claims, counterclaims and suggested explanations kept what was referred to as "cold fusion" or "fusion confusion" in the news.^[17]

On April 12, Pons received a standing ovation from about 7,000 chemists at the semi-annual meeting of the American Chemical Society. The University of Utah asked Congress to provide $25 million to pursue the research,^[18] and Pons was scheduled to meet with representatives of President Bush in early May.

Then on May 1, the American Physical Society held a session on cold fusion, which included several reports of experiments that failed to produce evidence of cold fusion. A second session began the next day with other negative reports, and eight of the nine leading speakers stated that they considered the initial Utah claim dead.^[19] Dr. Steven E. Koonin of Caltech described the Utah report as a result of "the incompetence and delusion of Pons and Fleischmann."^[19] Dr. Douglas R. O. Morrison, a physicist representing CERN, called the entire episode an example of pathological science.^[20]Nature published papers critical of cold fusion in July and November.^[21][22]

[edit] 1989 DOE panel

In November, a special panel formed by the Energy Research Advisory Board, under a charge of the United States Department of Energy, reported that they found the evidence for cold fusion to be unconvincing. Nevertheless, the panel was "sympathetic toward modest support for carefully focused and cooperative experiments within the present funding system."^[23]

The 1989 DOE panel said that it was not possible to state categorically that cold fusion has been convincingly either proved or disproved.^[24]

[edit] Further developments (1989-2004)

The first published replication of excess heat was reported by Richard Oriani while he was professor of physical chemistry at the University of Minnesota, in December 1990. The results were published in his paper, "Calorimetric Measurements of Excess Power Output During the Cathodic Charging of Deuterium Into Palladium", in Fusion Technology.^[25]

In 1991, Dr. Eugene Mallove stated that the negative report issued by the MIT Plasma Fusion Center in 1989, which was highly influential in the controversy, was fraudulent because data was shifted without explanation, obscuring a possible positive excess heat result at MIT. In protest of MIT's failure to discuss and acknowledge the significance of this data shift, Mallove resigned from his post as chief science author at the MIT news office on June 7, 1991. He maintained that the data shift was biased to support the conventional belief in the non-existence of the cold fusion effect as well as to protect the financial interests of the plasma fusion center's research in hot fusion.^[26]

The late Nobel Laureate Julian Schwinger (1918 - 1994) also stated in 1991 that he had experienced "the pressure for conformity in editor's rejection of submitted papers, based on venomous criticism of anonymous reviewers," and that "the replacement of impartial reviewing by censorship will be the death of science."^[27] He resigned as Member and Fellow of the American Physical Society in protest of its peer review practice on cold fusion.

In 1992, workers at General Electric challenged the Fleischmann-Pons 1990 report in the Journal of Electroanalytical Chemistry, stating that the claims of excess heat had been overstated.^[28] The challenge concluded that the Fleischmann and Pons cell generated 40% excess heat, more than ten times larger than the initial error estimate. Despite the apparent confirmation, Fleischmann and Pons replied to General Electric and published a rebuttal in the same journal.^[29]

Fleischmann and Pons relocated their laboratory to France under a grant from the Toyota Motor Corporation.

By 1991, 92 groups of researchers from 10 different countries had reported excess heat, tritium, helium4, neutrons or other nuclear effects.^[30] Over 3,000 cold fusion papers have been published including about 1,000 in peer-reviewed journals (see indices in further reading, below). In March 1995, Dr. Edmund Storms compiled a list of 21 papers and articles reporting excess heat published in peer reviewed journals such as Naturwissenschaften, European Physical Journal A, European Physical Journal C, Journal of Solid State Phenomena, Physical Review A, Journal of Electroanalytical Chemistry, Japanese Journal of Applied Physics, and Journal of Fusion Energy.

The generation of excess heat has been reported by (among others):

• Yoshiaki Arata, while he was professor at Osaka University, Japan,
• Robert A. Huggins, while he was professor at Stanford University (in March 1990),
• Michael McKubre, of SRI International,
• T. Mizuno (Hokkaido University, Japan),
• T. Ohmori (Japan),
• Richard A. Oriani, while he was professor at University of Minnesota (in December 1990),
• the late Giuliano Preparata, while he was at ENEA (Italy), and
• Edmund Storms, while he was at Los Alamos National Laboratory.

Many of these researchers continued their research in the phenomena after retirement.

Researchers share their results at the International Conference on Cold Fusion, recently renamed the International Conference on Condensed Matter Nuclear Science. The conference is held every 12 to 18 months in various countries around the world, and is hosted by The International Society for Condensed Matter Nuclear Science, a scientific organization that was founded as a professional society to support research efforts and to communicate experimental results. A few periodicals emerged in the 1990s that covered developments in cold fusion and related new energy sciences (Fusion Facts, Cold Fusion Magazine, Infinite Energy Magazine, and New Energy Times).

Between 1992 and 1997, Japan's Ministry of International Trade and Industry sponsored a "New Hydrogen Energy Program" of US$20 million to research cold fusion. Announcing the end of the program, Dr. Hideo Ikegami stated in 1997 "We couldn't achieve what was first claimed in terms of cold fusion." He added, "We can't find any reason to propose more money for the coming year or for the future."^[31]

In 1994, Dr. David Goodstein described cold fusion as "a pariah field, cast out by the scientific establishment. Between [cold fusion] and respectable science there is virtually no communication at all. Cold fusion papers are almost never published in refereed scientific journals, with the result that those works don't receive the normal critical scrutiny that science requires. On the other hand, because the Cold-Fusioners see themselves as a community under siege, there is little internal criticism. Experiments and theories tend to be accepted at face value, for fear of providing even more fuel for external critics, if anyone outside the group was bothering to listen. In these circumstances, crackpots flourish, making matters worse for those who believe that there is serious science going on here."^[32]

Cold fusion researchers said that cold fusion was being suppressed, and that skeptics suffered from "pathological disbelief".^[33] They said that there was virtually no possibility for funding in cold fusion in the United States, and no possibility of getting published.^[34] They said that people in universities refused to work on it because they would be ridiculed by their colleagues.^[35]

In February 2002, a laboratory within the United States Navy released a report^[36][37] that came to the conclusion that the cold fusion phenomenon was in fact real and deserved an official funding source for research.^[38] Navy researchers have now published more than 40 papers on cold fusion.^[39]

[edit] 2004 DOE panel

In 2004, the DOE organized another panel to take look at cold fusion developments since 1989 to determine if their policies towards cold fusion should be altered.^[40]

The nearly unanimous opinion of the reviewers in the 2004 review was that funding agencies should entertain individual, well-designed proposals for experiments that address specific scientific issues relevant to the question of whether or not there is anomalous energy production in Pd/D systems, or whether or not D-D fusion reactions occur at energies on the order of a few electron volts (eV). These proposals should meet accepted scientific standards and undergo the rigors of peer review. No reviewer recommended a focused federally funded program for low energy nuclear reactions. It stated that the field would benefit from the peer-review processes associated with proposal submission to agencies and paper submission to archival academic journals.^[41]

[edit] Recent developments

As of 2008, there are over 200 reports of excess heat and 60 reports of anomalous tritium production.^[α] Most scientists have met these reports with skepticism,^[42] although discussion in professional settings still continues. The American Chemical Society's (ACS) 2007 conference in Chicago held an "invited symposium" on cold fusion and low-energy nuclear reactions, and thirteen papers were presented at the "Cold Fusion" session of the 2006 American Physical Society (APS) March Meeting in Baltimore.^[43][44]

In 2008, the government of India reviewed the field.^[45] Dr. M. R. Srinivasan, former chairman of the Atomic Energy Commission of India said: "There is some science here that needs to be understood. We should set some people to investigate these experiments. There is much to be commended for the progress in the work. The neglect should come to an end".^[46] On May 22, 2008, Arata and Zhang publicly demonstrated what they say is a cold fusion reactor at Osaka University.^[47]

[edit] Summary of evidence for cold fusion

Cold fusion experiments have been conducted with many types of apparatus. The main constituents are:

• a metal, such as Palladium or Nickel, in bulk, thin films or powder;
• heavy or light water, hydrogen or deuterium gas or plasma;
• an excitation in the form of electricity or magnetism, of temperature or pressure cycle, of laser beam, or of acoustic waves.^[48]

More than ten groups have reported excess heat in a third of their experiments with a solid palladium cathode and an electrolyte with deuterium or D₂ gas loading of palladium powders. Most of those groups have sometimes seen 50-200% excess heat for hours to days. The groups' observed excess heat events have not diminished in frequency or magnitude, and they have improved their methods.^[49]

Cold fusion has remained controversial, but observations have been reported in experiments in electrolytic cells. Some experiments report excess heat, helium-4, low-level neutron production, X-ray emission, and transmutation of elements. None have unequivocally produced a particle emission spectrum matching that predicted by observations in nuclear science and high-energy physics. There is still no satisfactory theory explaining condensed matter nuclear science but many explanations have been proposed, several of which do not require new physics. As of 2007, the scientific community did not acknowledge this field as a genuine scientific research theme.^[50]

[edit] Excess heat

The excess power observed in some experiments is reported to be beyond that attributable to ordinary chemical or solid state sources; proponents attribute this excess power to nuclear fusion reactions.^[40]

The cold fusion researchers who presented their review document to the 2004 DOE panel said that "the hypothesis that the excess heat effect arises only as a consequence of errors in calorimetry was considered, studied, tested, and ultimately rejected".^[51] They said that over 50 experiments conducted by SRI International showed excess power well above the accuracy of measurement. Arata and Zhang said that, in one typical run, they observed excess heat power averaging 80 watts and output heat energy equal to 1.8 times input energy over 12 days.^[52] The researchers also said that the amount of energy reported in some of the experiments appeared to be too great compared to the small mass of the material in the cell for it to be stored by any chemical process. They said that their control experiments using light water did not show excess heat. There are nearly 200 published reports of excess heat by cold fusion researchers,^[53] and other researchers have written favorable reviews of these reports.^{[54][50][49][55][56]}

[edit] Nuclear products

The cold fusion researchers who presented their review document to the 2004 DOE panel on cold fusion said that there are insufficient chemical reaction products to account for the excess heat by several orders of magnitude.^[58] They said that three independent studies have shown that the rate of helium production measured in the gas stream varies linearly with excess power. Bursts of excess energy were time-correlated with bursts of ⁴He in the gas stream. Extensive precautions were taken to ensure that the samples were not contaminated by helium from the earth's atmosphere (5.2 ppm). They say that numerous studies have reported that ⁴He was produced at levels above that of the concentration in air.^[59] However, the amount of helium in the gas stream was about half of what would be expected for a heat source of the type D + D -> ⁴He. Searches for neutrons and other energetic emissions commensurate with excess heat have uniformly produced null results. There are over 60 published reports of anomalous tritium production,^[60] and other researchers have written favorable reviews of these reports.^{[61][50][49][55][62]}

In 2007, the Space and Naval Warfare Systems Center San Diego reported their observation of pits in CR-39 detectors during D/Pd codeposition experiments in the European Physical Journal. They said that those pits have features consistent with those observed for nuclear-generated tracks, that the Pd cathode is the source of those pits, and that they are not due to contamination or chemical reactions. They attributed some pits to knock-ons due to neutrons, and said that other pits are consistent with those obtained for alpha particles. They said that the experiment is reproducible.^[63]

[edit] Nuclear transmutations

In nuclear reactions, a chemical element may be transmuted into another. There are over 60 reports of nuclear transmutations and isotope anomalies in cold fusion experiments.^[64] Cold fusion proponents say that it is generally accepted that these anomalies are not the ash associated with the primary excess heat effect.^[58]

Tadahiko Mizuno was among the first to contribute a paper^[65] and a book on the subject.^[66] Dr. Miley, who also developed a process for making small inertial electrostatic confinement devices to serve as portable fusion neutron sources,^[67] wrote a review of these experiments.^[68] Some experiments result in the creation of only a few elements, while others result in a wide variety of elements from the periodic table. Calcium, copper, zinc, and iron were the most commonly reported elements. Lanthanides were also found: this is significant since they are unlikely to enter as impurities. In addition, the isotopic ratios of the observed elements differ from their natural isotopic ratio or natural abundance. The presence of an unnatural isotope ratio makes contamination an implausible explanation.^[69]

Iwamura and associates published further evidence of transmutations in the Japanese Journal of Applied Physics in 2002.^[70] Instead of using electrolysis, they forced deuterium gas to permeate through a thin layer of caesium deposited on calcium oxide and palladium, while periodically analyzing the nature of the surface through X-ray photoelectron spectroscopy. As the deuterium gas permeated over a period of a week, caesium appeared to be progressively transmuted into praseodymium. When caesium was replaced by strontium, it appeared to be transmuted into molybdenum with anomalous isotopic composition. In both cases this represents an addition of four deuterium nuclei to the original element. When the deuterium gas was replaced by hydrogen in control experiments, no transmutation was observed. The authors analyzed, and then rejected, the possibility of explaining these various observations by contaminations or migration of impurities from the palladium interior.^[71] The experiment was replicated by researchers from Osaka University, using Inductively Coupled Plasma Mass Spectrometry to analyze the nature of the surface.^[72]

[edit] Criticism

The skepticism towards cold fusion results from four issues: the precision of calorimetry, the lack of consistently reproducible results, the absence of nuclear products in quantities consistent with the excess heat, and the lack of a mainstream theoretical mechanism.^[73]

[edit] Precision of calorimetry

The efficacy of the stirring method in the Fleischmann-Pons experiment, and thus the validity of the temperature measurements has been disputed by Browne.^[74] The experiment has also been criticized by Wilson.^[75] Other experiments using open cells have been criticized by Shkedi^[76] and Jones.^[77] Other experiments using mass flow calorimetry have been criticized by Shanahan.^[78]

Cold fusion researchers find these critique unconvincing, and not applicable to other experimental design.^{[79][80][81][82]}

The 2004 DOE panel noted that significant progress has been made in the sophistication of calorimeters since 1989. Evaluations by the reviewers ranged from: 1) evidence for excess power is compelling, to 2) there is no convincing evidence that excess power is produced when integrated over the life of an experiment. The reviewers were split approximately evenly on this topic.^[40]

Many of the reviewers noted that poor experiment design, documentation, background control and other similar issues hampered the understanding and interpretation of the results presented to the DOE panel. The reviewers who did not find the production of excess power convincing said that excess power in the short term is not the same as net energy production over the entire time of an experiment, that such short-term excess power is only a few percent of the total external power applied and hence calibration and systematic effects could account for the purported effect, that all possible chemical and solid state causes of excess heat had not been investigated and eliminated as an explanation, that the magnitude of the effect had not increased after over a decade of work.^[40]

[edit] Lack of reproducibility of excess heat

The cold fusion researchers who presented their review document to the 2004 DOE panel on cold fusion said that the observation of excess heat has been reproduced, that it can be reproduced at will under the proper conditions, and that many of the reasons for failure to reproduce it have been discovered.^[83] Despite the assertions of these researchers, most reviewers stated that the effects are not repeatable.^[84]

In 1989, the DOE panel noted that "Even a single short but valid cold fusion period would be revolutionary. As a result, it is difficult convincingly to resolve all cold fusion claims since, for example, any good experiment that fails to find cold fusion can be discounted as merely not working for unknown reasons."^[24]

[edit] Missing nuclear products

The fusion of two deuterium nuclei usually produces either a tritium nucleus and a proton, or a helium-3 (³He) nucleus and a neutron. The level of neutrons, tritium and ³He actually observed in the Fleischmann-Pons experiments have been well below the level expected in view of the heat generated, implying that these fusion reactions cannot explain it. If the excess heat were generated by the fusion of two deuterium nuclei into helium (⁴He), a reaction which is normally extremely rare, gamma rays and helium (alpha particles) would be expected. In 1989, insufficient levels of helium (alpha particles) and gamma rays were observed to explain the excess heat.^[85]

When asked about evidence of low energy nuclear reactions, twelve of the eighteen members of the 2004 DOE panel did not feel that there was any conclusive evidence, five found the evidence "somewhat convincing", and one was entirely convinced. The evidence of D+D fusion was taken as convincing or somewhat convincing by some reviewers; for others the lack of consistency was an indication that the overall hypothesis was not justified. Contamination of apparatus or samples by air containing ⁴He was cited as one possible cause for false positive results in some measurements.^[86]

[edit] Lack of theoretical explanations

Temperatures and pressures similar to those in stars are required for conventional nuclear fusion. The 1989 DOE panel said that such "nuclear fusion at room temperature [...] would be contrary to all understanding gained of nuclear reactions in the last half century" and "it would require the invention of an entirely new nuclear process."^[23] but it also recognized that "the failure of a theory to account for cold fusion can be discounted on the grounds that the correct explanation and theory has not been provided",^[24] that is, the lack of a satisfactory explanation could not be used to dismiss experimental evidence.

Cold fusion observations are contrary to the conventional physics of nuclear fusion in several ways :

• The average density of deuterium atoms in the palladium rod seems vastly insufficient to force pairs of nuclei close enough for fusion to occur according to mechanisms known to mainstream theories. The average distance is approximately 0.17 nanometers, a distance at which the attractive strong nuclear force cannot overcome the Coulomb repulsion. Deuterium atoms are closer together in D₂ gas molecules, which do not exhibit fusion.^[87]
• There is no known mechanism that would release fusion energy as heat instead of radiation within the relatively small metal lattice.^[88] The direct conversion of fusion energy into heat is not possible because of energy and momentum conservation and the laws of special relativity.^[89]
• Transmutations introduce additional discrepancies between observations and conventional theory because of the increased Coulomb barrier.

Cold fusion researchers acknowledge these issues and have proposed various speculative theories (for a full review, see Storms 2007) to explain the reported observations, but none has received mainstream acceptance.^[50]

[edit] Notes

[edit] References

[edit] Bibliography

[edit] Further reading