Meanwhile, at Lawrence Livermore National Laboratory in California, the world's most powerful laser has emerged from the shadows of classification. Nova jams trillions of watts of light into its pulses, which last only billionths of a second. With Nova, physicists study laser fusion, in which a laser's output splits into dozens of synchronized pulses, all converging at once on a frozen pellet of hydrogen. The resulting implosion should compress the hydrogen so sharply that it ignites a tiny thermonuclear blast. While funded under the aegis of atomic-weapons research, Nova has shed light on astrophysics and the possibility of harnessing laser fusion to generate electricity.
Nova lifts a trick from thermonuclear weaponry to touch off fusion.
The laser pulses don't slam directly into the hydrogen pellet. Instead, they burst simultaneously into a small gold-lined capsule, called a holmraum, that encloses the pellet. The sudden energy jolt vaporizes the gold lining into a plasma. Then a wave of X-rays radiates inside the holmraum and, like a clenching fist, crushes the pellet into fusion. The technique, known as indirect drive, ensures a uniform confluence of energy from all directions upon the fuel pellet.