- Scientists managed to produce more energy than was used to activate the reaction
- Around 192 lasers heated a target the size of a peppercorn to more than 180 million degrees Fahrenheit
- The energy production took less time than it takes light to travel one inch
- Nuclear fusion is what powers the sun and stars - and has been the 'holy grail' for scientists who believe this clean energy source will replace the use of fossil fuel
The US Department of Energy has announced an accomplishment in nuclear fusion that will go down in history - marking a decades-long quest to harness the same energy that powers the sun and stars.
Scientists achieved the holy grail of 'net energy gain' by producing more energy in fusion than was used to activate it.
They made the breakthrough on December 5, at the Lawrence Livermore National Laboratory's National Ignition Facility (NIF) in California, which houses a sports stadium-sized lab equipped with 192 lasers.
The experiment saw the high-energy lasers converge on a target about the size of a peppercorn, heating a capsule of hydrogen to more than 180 million degrees Fahrenheit and 'briefly simulating the conditions of the sun,' said the facility's director, Dr Kim Budil.
Energy Secretary Jennifer Granholm called the breakthrough a 'landmark achievement.'
Granholm said scientists at Livermore and other national labs are working on research to help the US 'solve humanity's most complex and pressing problems, like providing clean power to combat climate change and maintaining a nuclear deterrent without nuclear testing.'
Nuclear fusion is the process by which two light atomic nuclei combine to form a single heavier one, while releasing massive amounts of energy.
In the case of Earth's sun and the stars in space, nuclei need to collide with each other at extremely high temperatures, more than ten million degrees Fahrenheit.
The high temperature gives the nuclei enough energy to overcome their mutual electrical repulsion.
Once the nuclei come within a very close range of each other, the attractive nuclear force between them will outweigh the electrical repulsion and allow them to fuse. For this to happen, the nuclei must be confined within a small space to increase the chances of collision.
The extreme pressure produced by its immense gravity creates the conditions for fusion in the sun.
Unlike fission, fusion carries less risk of accidents or the theft of atomic material.
Nuclear fission occurs when a neutron slams into a larger atom, forcing it to excite and split into two smaller atoms. This is what happens in nuclear power plants. But nuclear fusion has been a sought-after achievement for nearly 70 years.
The team pulled inspiration from researchers in the 1960s that theorized lasers could induce fusion in a laboratory. And this kickstarted the decades-long work to develop those lasers and optics, diagnostics, target fabrication, computer modeling and simulation and experimental design. The lasers used in the experiment can create temperatures and pressures similar to those in the core of stars and giant planets, and inside exploding nuclear weapons.
The team used 2.1 megajoules of energy to create the reaction conditions, replicating the power of the sun. This resulted in an output of 3.15 megajoules - a gain of around 150 percent. 'Ignition allows us to replicate for the first time certain conditions that are only found in the stars and sun,' Granholm said Tuesday.
'This milestone moves us one significant step closer to the possibility of zero carbon abundant fusion energy powering our society.' She opened the live briefing with the statement that 'this is what it looks like for America to lead.
' While Tuesday's announcement is a step toward clean energy, the scientists are not blind to the work still ahead. Budil said there are still 'significant hurdles' to overcome before the technology can be available commercially. 'I think it's moving into the foreground — and probably with concerted effort and investment, a few decades of research on the underlying technologies could put us in a position to build a power plant,' she added. Net energy gain has been the holy grail for scientists, as fusion happens at such high temperatures and pressures that it are incredibly difficult to control.
Billions of dollars and decades of work have gone into fusion research that has produced exhilarating results - for fractions of a second. Riccardo Betti, a professor at the University of Rochester and expert in laser fusion, said the fact that net energy had been gained in a fusion reaction is significant.
But he said there is a long road ahead before the result generates sustainable electricity. He likened the breakthrough to when humans first learned that refining oil into gasoline and igniting it could produce an explosion.
'You still don't have the engine and you still don't have the tires,' Betti said. 'You can't say that you have a car.' White House science adviser Arati Prabhakar, appearing with Granholm, called the fusion ignition 'a tremendous example of what perseverance really can achieve' and 'an engineering marvel beyond belief.'' Proponents of fusion hope that it could one day produce nearly limitless, carbon-free energy, displacing fossil fuels and other traditional energy sources.
Producing energy that powers homes and businesses from fusion is still decades away. But researchers said it was a significant step nonetheless. Michael Mann, with the Department of Earth and Environmental Science at the University of Pennsylvania, took to Twitter to share his skepticism on the announcement. He shared that the fusion breakthrough is not enough to eliminate the need for fossil fuels just yet.
'That doesn't mean it isn't good news, but it does mean that it won't play a significant role in decarbonizing our economy by 50% this decade, which is necessary to avert catastrophic >1.5C (3F) warming,' Mann shared. 'We can do that w/ existing renewables + storage/efficiency/conservation.
' The ultimate goal, still years away, is to generate power the way the sun creates heat by pushing hydrogen atoms so close to each other that they combine into helium, which releases torrents of energy.
A single cupful of that substance could power an average-sized house for hundreds of years without carbon emissions.
That is why fusion is considered the holy grail of energy in a world with an ever-increasing demand for electricity and a deteriorating environment. It merges atomic nuclei to create massive amounts of energy — the opposite of the fission process used in atomic weapons and nuclear power plants, which splits them into fragments.
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