An almost limitless supply of clean energy has been brought one step closer to reality.
Scientists have developed a new way to make plasma fuel hot and dense enough to generate ‘significant’ fusion power.
While using nuclear fusion to power homes and businesses may still be some way off, the new plasma marks a major step in fusion power research.
Nuclear fusion is being looked to as a potentially limitless source of clean energy, created by the same core processes inside the sun.
Using intense heat, magnetic fields and pressure, the nuclei of lighter elements are fused together to create heavier elements, releasing energy in the process.
By containing this star-like process in specially designed reactors, engineers can fuse hydrogen atoms together to produce helium, harnessing the clean energy produced and potentially cutting dependency on fossil fuels.
In order for the reaction to take place, the super-heated gas – in a plasma state – is subjected to pressure, which essentially squeezes the atoms together and forced them to react.
Now, researchers from MIT, have come up with a new type of plasma to increase the amount of energy produced.
And during trials, the new plasma has resulted in raising trace amounts of ions to megaelectronvolt (MeV) energies – an order of magnitude greater than previously achieved.
Dr John Wright, one of the researchers working on the study, said: ‘These higher energy ranges are in the same range as activated fusion products.
‘To be able to create such energetic ions in a non-activated device – not doing a huge amount of fusion – is beneficial, because we can study how ions with energies comparable to fusion reaction products behave, how well they would be confined.’
In most reactors, the plasma would be made up of just two ion species – deuterium and hydrogen or deuterium and helium-3, with deuterium dominating the mixture by up to 95 per cent.
But the new approach uses a fuel made up of three ion species: hydrogen, deuterium, and trace amounts of helium-3.
The scientists focus energy on the helium-3, which heats up to much higher energies because of its smaller fraction of the total density.
This allows the plasma to reach the range of activated fusion products.
The researchers tested the plasma in the Alcator C-Mod reactor – MIT’s custom tokamak – with help from researchers from the Laboratory for Plasma Physics in Brussels.
The successful results on C-Mod provided proof of principle – enough to get scientists at the UK’s Joint European Torus (JET), Europe’s largest fusion device, interested in reproducing the results.
Dr Wright added: ‘The JET folks had really good energetic particle diagnostics, so they could directly measure these high energy ions and verify that they were indeed there.
‘The fact that we had a basic theory realized on two different devices on two continents came together to produce a strong paper.’
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