Harnessing the Stars: EU to Attempt Laser-based Fusion

Scientists have conceived of a number of approaches to harness fusion—the same source of energy that heats the stars—as a future nonpolluting energy source. The hope is to tap into the same “star power” that exists throughout the universe.

The Sun itself is a natural fusion reactor, but scientists believe that laser technology may now be powerful enough to create safe, clean, and convenient fusion energy. Such advancement could potentially end the world's energy crisis.

“Fusion is basically nature’s solution to the energy problem,” said researcher Mike Dunne. “It’s how the Sun and the stars work. We’re just a couple of years away from seeing it in the lab. The public will then be asking what’s next, and we’ll be in a position to take it forward. It is still a way off – this is not going to solve the immediate problem of greenhouse gases. But it should make sure we never again fall into the trap of polluting to meet our energy needs.”

European scientists now have the green light to build on U.S. military scientist’s research to try to create laser-based nuclear fusion aimed at replacing fossil fuels. A team of British-led scientists has received approval from the European Union for the project, which would produce almost no greenhouse gases or long-lived radioactive waste.

While the U.S. military scientists has already developed the basic technology needed, so far the energy required to reach the temperatures at which such reactions occur, has outweighed the energy produced. However, more advanced laser technologies are expected to change that equation.

The project will use the world's most powerful laser to generate temperatures of millions of degrees. The British-led team will use lasers to ignite fusion reactions that generate more energy than they consume. After winning the backing of an influential EU science panel, the project will receive a seven-year, £500 million budget to construct an experimental reactor based on a revolutionary technique that is expected to make fusion a commercial reality by mid-century.

The prototype for the Hiper (high energy laser fusion research) project is likely to be built in Britain, using the world’s most powerful laser to generate temperatures of millions of degrees at which fusion can occur. The civilian facility will build on the US military successes, and is expected within the next five years to achieve a form of laser fusion to produce more energy than it consumes—the first benchmark towards commercial viability. Hiper will then develop a slightly different laser technique that is more suitable for wide-scale commercial use.

If it works, laser fusion power stations could be supplying most of the world’s energy needs by the middle of the century, replacing fossil fuels and nuclear fission with a technology that produces next to no greenhouse gases or long-lived radioactive waste.

The Hiper approach has been endorsed by peer-reviewers for the European Commission. But the EU is hedging the bet, by also backing an alternative approach. A reactor to be built in France by 2016 will not use lasers, but conventional “hot fusion” contained by superconducting magnets.

Nuclear fusion involves merging two types of hydrogen atom – deuterium and tritium – to make helium, as well as neutrons that release vast quantities of energy. Almost limitless amounts of deuterium fuel can be made cheaply from seawater, tritium being produced as a byproduct in the reactor itself.

The extremely high temperature at which the reaction takes place requires magnetic containment facilities, as terrestrial materials would instantly melt in contact with the reaction. However, lasers can be used to create these temperatures specifically at the point of fusion, so that containment of the reaction becomes less of a problem.

For example, a pulsed laser with a power of a petawatt (a million billion watts) is directed at a fuel pellet two millimeters across. The vast pressure this creates compresses the pellet to a diameter of few microns and generates temperatures of tens of millions of degrees, allowing fusion to begin.

Professor Dunne, of the Rutherford Appleton Laboratory in Oxfordshire, explained, “To put that in perspective, it [the laser] is 10,000 times the power of the entire UK National Grid. And then you’re going to focus that down onto a spot that’s 10 to 100 times smaller than the width of a human hair. The pressure is equivalent to 10 Nimitz class aircraft carriers sitting on your thumb. Some pretty crazy things are going to happen, and that’s what we’re about.”