In nuclear physics and nuclear chemistry, nuclear fusion is the process by which multiple like-charged atomic nuclei join together to form a heavier nucleus. It is accompanied by the release or absorption of energy, which allows matter to enter a plasma state.
Nuclear fusion occurs naturally in stars. Artificial fusion in human enterprises has also been achieved, although has not yet been completely controlled.
Now the National Ignition Facility, which is the size of 3 football fields, consists of 192 separate laser beams, each traveling 1,000 feet in one-thousandth of a second to converge simultaneously on a target the size of a pencil eraser.
Federal officials said they planned to use it on a assignment that would include ensuring aging nuclear weapons are functioning properly without resorting to underground testing.
Other uses will include the study of astrophysics and experiments in developing green energy programs.
Beginning next year, scientists also will use the laser for experiments aimed at creating controlled fusion reactions similar to those found in the sun.
"More energy will be produced by this ignition process than the amount of laser energy required to start it. This is the long-sought goal of energy gain that has been the goal of fusion researchers for more than half a century," said NIF director Edward Moses.
The laser will be used in astrophysics, allowing scientists to mimic conditions inside planets and new solar systems, something the lab's officials said would allow for conducting experiments that could never be undertaken on Earth before.
Research into controlled fusion, with the aim of producing fusion power for the production of electricity, has been conducted for over 50 years. It has been accompanied by extreme scientific and technological difficulties, but resulted in steady progress. At present, break-even (self-sustaining) controlled fusion reactions have been demonstrated in a few tokamak-type reactors around the world. These have enabled the creation of workable designs for a reactor which will deliver ten times more fusion energy than the amount needed to heat up plasma to required temperatures (see ITER which is scheduled to be operational in 2018).