Introduction
Cold fusion is a nuclear effect discovered by Martin Fleischmann and Stanley Pons in the 1980s. They announced the discovery in March 1989 at the University of Utah.
Cold fusion occurs under certain conditions in metal hydrides (metals with hydrogen or heavy hydrogen dissolved in them). The effect also produces charged particles, and occasionally a very low level of neutrons. In some experiments the host metal has been transmuted into other elements. The cold fusion reaction has been seen with palladium, titanium, nickel, and some superconducting ceramics.
The heat from cold fusion in many experiments far exceeds the amount of heat that can be produced by chemical fuel. In some cases, cold fusion devices the size of a coin weighing a few grams have produced as much energy as several kilograms of gasoline.
Most of the research has been with palladium. The control parameters for palladium are well understood. They include mainly high loading, flux and current density. It is difficult to meet these necessary conditions, because many samples of palladium are flawed and do not load to high levels. However, when the conditions are met the effect nearly always occurs, as shown in Fig. 1. Heat appears at loading above 0.94, and it seldom appears below 0.90. When current density is raised, the heat responds proportionally (Fig. 2).
Fig. 1. Excess Power vs. Maximum Loading.
Fig. 2. Simultaneous Series Operation of Light & Heavy Water Cells; Excess Power vs. Current Density.
In recent years, promising results have been obtained with nickel and many researchers are now focusing on this material. Nanoparticle palladium and nickel seem especially promising.
There is no universally accepted theoretical explanation for cold fusion. Several theoreticians believe they can explain it, but other theoreticians disagree with them. Many experimentalists feel that the theories proposed so far have not been a useful guide for further research.
Why this is called cold fusion, LENR, CANR and other names
Soon after the effect was first announced people began calling it cold fusion. Various other names have been proposed over the years including the Fleischmann-Pons effect, LENR (low energy nuclear reactions) and so on. LENR has become the most commonly used in recent years. All of these names mean the same thing.