A newly-published study describes how for the first time, scientists have been able to generate more energy through an experiment than was used to initiate nuclear fusion. For more than 50 years, researchers have struggled to harness the same physical process that fuels the sun in order to use it to generate a powerful source of sustainable energy here on Earth. While only a small amount of material was used in this experiment and the technology is years away from commercial use, this announcement represents a major breakthrough in the field.
In order to produce this energy, researchers at the Lawrence Livermore National Laboratory used 192 lasers to heat a 1-centimeter cylinder millions of degrees. In the center of the cylinder is a tiny plastic pellet containing the fuel in the form of hydrogen plasma. As the cylinder heats, x-rays are produced which compress the gas and cause the pellet to explode. Finally, 1/200ths of the energy from the lasers reachers the hydrogen atoms in the center, causing them to fuse. Using this technique, scientists were able to produce 2.6 times more energy than the fuel originally received — a world first and a rate 10 times better than any previous experiments.
There’s still a long way to go before this technology could be a viable power source, however. For one thing, only a tiny fraction of the energy used actually reaches the hydrogen fuel in this model, so it still takes enormous amounts of energy to run the reactor. This experiment was also unable to achieve ignition, the point at which a chain reaction occurs and fusion becomes self-sustaining. In order to reach that point, the hydrogen would have to reach temperatures hundreds of times higher and be subject to thousands of times more pressure.