On Wednesday, U.S. scientists at the federally funded Lawrence Livermore National Laboratory in California said that for the first time experiments have produced more energy from fusion reactions than the amount of energy put into the fusion fuel, meaning the fusion reaction broke even. The ground-breaking research was conducted at the laboratory's National Ignition Facility (NIF), which is funded by the U.S. Department of Energy's National Nuclear Security Administration.

Fusion is a reaction in which two atoms of hydrogen combine together to form an atom of helium, in the process, converting some of the mass of the hydrogen into energy. Fusion is the process that powers the sun and other stars and has the potential to be an inexhaustible source of energy. Unlike current nuclear fission energies based on splitting atoms, fusion energy is instead produced by fusing two atoms together.

Scientists have previously used doughnut-shaped reactors called tokamaks in another type of magnetic confinement to compress the hydrogen fuel. In the '90s, the Joint European Torus experiment in England generated 16 million watts of fusion power, producing about 70 percent of the power consumed. An international project named ITER is building a large tokamak reactor in France which is scheduled to start running in 2020.

"Really for the first time anywhere, we've gotten more energy out of this fuel than was put into the fuel. And that's quite unique. And that's kind of a major turning point, in a lot of our minds," said physicist Omar Hurricane, who heads the team of researchers. "I think a lot of people are jazzed."

Scientists stated that the self-heating nuclear fusion known as ignition necessary for a fusion power plant was not achieved, however, and that much more work was needed before fusion can become a viable energy source. "I wish I could put a date on it," he said. "But it really is (just) research. And, you know, although we're doing pretty good, we'd be lying to you if we told you a date."

In order to make fusion happen, the atoms of hydrogen must be heated to extremely high temperatures of 100 million degrees so they are ionized, forming a plasma, and therefore have sufficient energy to fuse. Then they need to be held together or confined in a small space long enough for the fusion reaction to occur. The easiest fusion reaction to make is by combining deuterium (also known as "heavy hydrogen) with tritium (known as "very heavy hydrogen") in order to make helium and a neutron. This is the most practical way for humans to do fusion because deuterium is plentifully available in ordinary water. Tritium can be produced by combining the abundant light metal lithium with the fusion neutron.

Unlike current energy sources of fossil fuels or fission found in nuclear power, fusion would also be environmentally friendly and produce no combustion products or greenhouse gases, which would allow us to stop polluting the earth with unclean energy sources. Fusion is a nuclear process but unlike traditional nuclear power plants, the products of the fusion reaction, helium and a neutron, are not radioactive meaning that if designed properly a fusion power plant would be safe and produce no radioactive waste. Studies have shown that electricity from fusion would be about the same cost as present day sources, potentially becoming even cheaper, while being much cleaner to produce.

The sun and stars achieve confinement through the use of gravity, but since that cannot easily be replicated here on Earth, a more practical approach is magnetic confinement or using a strong magnetic field to hold together the ionized atoms and then heat them by microwaves or other energy sources. Another such method is inertial confinement, wherein a small mass of frozen hydrogen is compressed and heated by a dose of very intense energy so quickly that fusion occurs before the atoms can fly apart, something which can be achieved by a laser.

The scientists reportedly trained 192 laser beams on a capsule less than a tenth of an inch in diameter, creating conditions of up to three times the density of the sun. The capsule was filled with a fusion fuel consisting of plasma of deuterium and tritium, which are two isotopes of hydrogen, with the fuel inside the capsule frozen in a layer less than the width of a human hair. Under the high temperatures of the laser beam, the nuclei of the deuterium and tritium fuse releasing a neutron, an alpha particle, and energy.

Compared with two experiments by the researchers that took place in September and November last year, in the latest experiment published in the journal Nature, more energy came out of the fusion fuel than was deposited into it and the deuterium-tritium implosions were made more stable than previously achieved by doubling the laser power compared to previous tries. The fusion energy yield had increased by about tenfold from past experiments although the yield was still less than the total amount deposited into the target.

According to nuclear experts, the new results will both help the project gain more taxpayer support and give it more time before critics can assess the project's ultimate worth. The project is currently being financed by the federal Department of Energy to the tune of about $330 million (that's the budget for this year). The total cost for building and operating the project so far has been over $5.3 billion.

"A lot of people were saying it should be killed off," said Stephen E. Bodner, a director at the Naval Research Laboratory in Washington. "Now, the general view is that they're doing much better science. There's been a significant improvement."

"I believe a compact carbon-free energy source is very important for humankind in the long term," said Mark Herrmann, a fusion researcher at Sandia National Laboratories in New Mexico, also overseen by the U.S. National Nuclear Security Administration. "Fusion is one bet. If it pays off, the return will be big."

Scientists have been trying to make fusion work for over 40 years because succeeding means there will exist an inexhaustible energy source. This inexhaustible energy source could literally end poverty and all resource shortages and bring about the future seen in science fiction shows and movies. One out of every 6,500 atoms of hydrogen in water is deuterium, meaning a gallon of water has the same energy content as 300 gallons of gasoline.

The United States and other nations have invested millions of dollars into fusion research because the potential this type of energy offers could reduce dependence on oil and other fossil fuels. Both the British national laboratory for fusion research, the Culham Centre for Fusion Energy, and the Princeton Plasma Physics Laboratory in New Jersey are researching the fusion via magnetic confinement by putting plasma in a magnetic container and heating it up until the deuterium and tritium nuclei fuse.

"We have waited 60 years to get close to controlled fusion, and we are now close in both magnetic and inertial confinement research. We must keep at it," said Steve Cowley, director of the Culham Centre.