Researchers at the National Ignition Facility (NIF), at Lawrence Livermore National Laboratory (LLNL) in California, say the facility is finally near to reaching productive nuclear fusion after decades of experiments and challenges.
This puts the facility in a race against a handful of other major fusion projects worldwide that also claim to be close to the goal of fusion ignition, Popular Mechanics reports.
Approaching the 'burning plasma' milestone
NIF researchers believe they are close to an important milestone known as 'burning plasma'.
'Burning plasma' entails "a fusion burn sustained by the heat of the reaction itself rather than the input of laser energy," Science's Daniel Clery writes.
Fusion critics argue that the incredible cost of decades of costly experiments could mean that the major projects never recoup their costs. However, advocates argue that we are now closer than ever to the extraordinary goal of nuclear fusion.
In the NIF, almost 200 lasers are trained on a tiny amount of nuclear fuel. The laser beams don't actually reach the fuel. Instead, they "heat a gold can the size of a pencil eraser called a hohlraum, which emits a pulse of x-rays meant to ignite fusion by heating the fuel capsule at its center to tens of millions of degrees and compressing it to billions of atmospheres," Science reports.
Design and strategy adjustments
Over the last few years, the researchers at NIF have tried several strategies that have led to improved outcomes in their trajectory towards nuclear fusion.
For example, they changed the shape of the crucible in the reactor and tweaked other parts of the experimental design. Their method has also been tweaked: during the process "later [laser] pulses [were] ramped up more aggressively so that the plastic capsule had less time to mix with the fuel during compression." This tactic "boosted yields somewhat,” Nature explains.
Of course, when it comes to nuclear fusion reactors, a race towards a new milestone will likely still take years to be decided. The researchers at the NIF seem fairly confident the exciting 'burning plasma' milestone will take years, not decades, to reach.