Tuesday, 8 October 2013
Nuclear fusion getting closer
Harnessing fusion - the process that powers the Sun - could provide an unlimited and cheap source of energy.
To be viable, fusion power plants would have to produce more energy than they consume, which has proven elusive, and ultimately pointless
Now, a breakthrough by scientists at the National Ignition Facility (NIF) could boost hopes of scaling up fusion.
NIF, based at Livermore in California, uses 192 beams from the world's most powerful laser to heat and compress a small pellet of hydrogen fuel to the point where nuclear fusion reactions take place.
The BBC understands that during an experiment in late September, the amount of energy released through the fusion reaction exceeded the amount of energy being absorbed by the fuel - the first time this had been achieved at any fusion facility in the world.
This is a step short of the lab's stated goal of "ignition", where nuclear fusion generates as much energy as the lasers supply. This is because known "inefficiencies" in different parts of the system mean not all the energy supplied through the laser is delivered to the fuel.
X-rays strip material from the outer shell of the fuel pellet, heating it up to millions of degrees
If the compression of the fuel is high enough and uniform enough, nuclear fusion can result
But the latest achievement has been described as the single most meaningful step for fusion in recent years, and demonstrates NIF is well on its way towards the coveted target of ignition and self-sustaining fusion.