Scientists have discovered that sprinkling a form of fusion plasma powder may help collect ultra-hot gas in a heating plant to produce electricity without greenhouse gasses or long-term nuclear waste.
The study was conducted by scientists at the US Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL).
Fusion, the power that drives the sun and stars, combines light elements in the form of plasma that generates massive amounts of energy. Scientists are seeking to replicate fusion on Earth for a virtually inexhaustible supply of power to generate electricity.
After reporting the results of the paper in 'Nuclear Fusion' Rober Lunsford, a physicist, said: "The main goal of the experiment was to see if we could lay down a layer of boron using a powder injector. So far, the experiment appears to have been successful."
The boron prevents an element known as tungsten from leaching out of the tokamak walls into the plasma, where it can cool the plasma particles and make fusion reactions less efficient.
To maximise fusion reactions and hence the heat to create electricity, scientists want to keep their plasma as hot as possible, at least ten times hotter than the surface of the sun.
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"Diborane gas is explosive, so everybody has to leave the building housing the tokamak during the process," said Lunsford.
"On the other hand, if you could just drop some boron powder into the plasma, that would be a lot easier to manage. While diborane gas is explosive and toxic, boron powder is inert. This new technique would be less intrusive and dangerous," said he.
Another advantage is that while physicians have to interrupt boron gas procedures, boron powder can be applied to the plasma while operating the system. This feature is important as future fusion plants will have to last for long, uninterrupted periods to ensure they provide a constant source of electricity.
There are other reasons to use a powder dropper to coat the inner surfaces of a tokamak.
For instance, researchers found that the injection of boron powder helps the plasma with the pounding of nitrogen gas - both strategies increase plasma edging pressure, thus enhancing the degree to which the plasma remains contained in the magnetic fields.
Being able to create a wide range of plasma conditions easily in this way would enable physicists to explore the behaviour of plasma more thoroughly.
In the future, Lunsford and the other scientists in the group hope to conduct experiments to determine where, exactly, the material goes after it has been injected into the plasma.
Physicists currently hypothesise that the powder flows to the top and bottom of the tokamak chamber, the same way the plasma flows, "but it would be useful to have that hypothesis backed up by modeling so we know the exact locations within the tokamak that are getting the boron layers," added Lunsford.