In March 1989, newspapers across the world had headlines like "Electrochemists Discover Source of Clean, Unlimited Energy!" The associated stories told of the discovery by two University of Utah scientists, Stanley Pons and Martin Fleischmann, who claimed to have created room-temperature nuclear fusion in a jar.
What is nuclear fusion?
Fusion is the process where two or more atomic nuclei combine to form one or more different atomic nuclei and subatomic particles, such as neutrons or protons. The difference in mass between the nuclei you start with and those you end with is converted into energy according to Einstein's famous formula E = mc2, where E is the amount of energy, m is the mass, and c2 is the speed of light squared.
Fusion is what powers stars such as our Sun, and thermonuclear, or hydrogen, bombs. On the surface of the Sun, where temperatures reach 15,000,000 degrees C, and pressures are enormous, hydrogen atoms fuse and produce helium atoms.
To create fusion here on Earth, you first need to create a plasma, which is an ionized state of matter similar to a gas. In a plasma, electrons are separated from atomic nuclei, and the plasma is comprised of charged particles — positive nuclei and negative electrons.
To create a fusion plasma, you need to satisfy three conditions:
1. Very high temperature to provoke high-energy collisions
2. Sufficient plasma particle density so that collisions occur
3. Sufficient time to confine the plasma within a defined volume.
Since the plasma is hot enough to melt any containment vessel it touches, it must be corralled by something other than matter, and in tokamak devices, that something is magnetic fields.
A tokamak is a device which uses a powerful magnetic field to confine a hot plasma in the shape of a torus, which is a donut shape. Atoms of deuterium or tritium fuse to form one helium nucleus, one neutron, and a spectacular amount of energy.
Deuterium is an isotope of hydrogen having a nucleus containing one proton and one neutron. This is double the mass of an ordinary hydrogen nucleus which contains only one proton. Tritium is a beta-emitting radioactive isotope of hydrogen with a nucleus containing one proton and two neutrons. Tritium is three times as heavy as ordinary hydrogen, and 1.5 times as heavy as deuterium. Deuterium is found in ordinary sea water at 150 parts per million.
An example of a tokamak type of reactor is the I.T.E.R. reactor in France.
Another type of nuclear fusion reactor is called an inertial confinement reactor. It uses pulses from ultra powerful lasers to heat the surface of a pellet of fuel until it implodes. This makes it hot enough and dense enough for its atoms to fuse. An example of this type of reactor is the National Ignition Facility in the U.S.
The bottom line is that nuclear fusion creates four times more energy than nuclearfission, and four million times more energy than a chemical reaction, such as the burning of gas, oil or coal. A single glass of sea water could produce the same amount of energy as burning a barrel of oil, and it would release no waste. Fusion could supply all of mankind's energy needs without contributing to global warming.
The cold fusion fiasco
All this is why Pons' and Fleischman's announcement of room-temperature nuclear fusion in a jar sounded so appealing. Pons and Fleischmann had filled a bottle with heavy water, which is water comprised of deuterium and oxygen. They then passed an electric current from a palladium cathode through the heavy water, and the palladium absorbed deuterium atoms, which according to Pons and Fleischmann, forced them to fuse, and generated heat and neutrons.
After the University of Utah announced the discovery on March 23, 1989, scientists around the world tried to replicate the experiment. A team led by Dr. Nathan Lewis at the California Institute of Technology used more sensitive equipment than the Utah team had used, and they found no fusion had taken place. They also found that no neutrons, gamma rays, tritium or helium were emitted, as the Utah team had claimed.
By May, 1989 physicists at a meeting of the American Physical Society in Baltimore, Maryland unleashed a torrent of attacks on Pons and Fleischmann. Dr. Lewis told the 1,800 assembled physicists that "Pons would never answer any of our questions ..." Dr. Steven E. Koonin of Caltech described the Utah experiment as the result of "the incompetence and delusion of Pons and Fleischmann."
A University of Maryland scientist had asked Dr. Pons to come to the A.P.S. meeting in Baltimore, but Pons had responded that "... he would be too busy discussing cold fusion with a Congressional committee to come to Baltimore."
Other institutions piled on, including the Massachusetts Institute of Technology, Lawrence Berkeley Laboratory, the University of Rochester, Brookhaven National Laboratory, Yale University and CERN.
In response, University of Utah director of research, Dr. James Brophy, said, "It is difficult to believe that after five years of experiments Dr. Pons and Dr. Fleischmann could have made some of the errors I've heard have been alleged at the American Physical Society meeting." The criticism came just after the University of Utah had asked the U.S. Congress to provide $25 million to pursue Pons' and Fleischmann's research.
In January 1991, Pons left the University of Utah and moved to France where he and Fleischmann resumed their research with the backing of the Toyota Motor Corporation's IMRA lab. The cold fusion experiment was shuttered in 1998 after spending $40 million with no tangible results found.
While Pons has made no public declarations since, Fleischmann has continued giving talks and publishing papers.
Cold fusion in the media
The Pons-Fleischmann experiment has appeared on The Simpsons. The 1990 film Bullseye! referenced the experiment, and the 2012 documentary The Believers was about Pons and Fleischmann. Adobe ColdFusion was named after the experiment, as was a brand of protein bars manufactured by Cold Fusion Foods.
And, in the last scene of the beloved 1985 movie, Back to the Future, Doc Brown uses cold fusion to power his Delorean time machine and take Marty and Jennifer "back to the future."