How donut-shaped fusion plasmas managed to decrease adverse turbulence

February 27, 2017
Credit: Springer

Fusion research has been dominated by the search for a suitable way of ensuring confinement as part of the research into using fusion to generate energy. In a recent paper published in EPJ H, Fritz Wagner from the Max Planck Institute for Plasma Physics in Germany, gives a historical perspective outlining how our gradual understanding of improved confinement regimes for what are referred to as toroidal fusion plasmas—confined in a donut shape using strong magnetic fields— have developed since the 1980s. He explains the extent to which physicists' understanding of the mechanisms governing turbulent transport in such high-temperature plasmas has been critical in improving the advances towards harvesting fusion energy.

The release of energy from processes between deuterons and tritons (DT-fusion) requires high temperatures to overcome the Coulomb potential, high density for frequent collisions and a high energy confinement time. Plasma is composed of light negative and heavy positive charges with strongly different mobilities. However, increasing the pressure by additional heating to bring the closer to the fusion conditions causes turbulence to become more violent so that is degraded.

The level of adverse turbulence ultimately reduces the prospects of fusion. Physicists found in the 1980s that toroidally shaped plasmas of the tokamak type offer a path to low turbulence thanks to their ability to self-organise. Over the course of the past 30 to 40 years, they came to realise that turbulence and plasma flow are linked and regulate each other. Indeed, they found that the spatial variation of the plasma flow regulates the turbulence of the drift-wave type. They also found that this mechanism is another example of a self-organisation process known for a long time in geophysical fluid dynamics.

Explore further: Turbulent transport of hydrogen fuel in fusion plasmas

More information: F. Wagner, The history of research into improved confinementregimes, The European Physical Journal H (2017). DOI: 10.1140/epjh/e2016-70064-9

Related Stories

Turbulent transport of hydrogen fuel in fusion plasmas

December 16, 2016

Using large-scale computer simulations, the Plasma Physics and Fusion Energy research group at the Department of Earth and Space Sciences is making important contributions to Joint European Torus (JET), the biggest fusion ...

A turbulent solution to a growing problem

October 27, 2016

A recent experiment lead by University of California, Los Angeles (UCLA), researchers on the DIII-D tokamak suggests that plasma turbulence can prevent filamentary structures called magnetic islands from growing so large ...

Identifying new sources of turbulence in spherical tokamaks

November 25, 2015

For fusion reactions to take place efficiently, the atomic nuclei that fuse together in plasma must be kept sufficiently hot. But turbulence in the plasma that flows in facilities called tokamaks can cause heat to leak from ...

Scientists move step closer to solving fusion plasma dilemma

September 12, 2016

A team of researchers, affiliated with UNIST claims to have made yet another step towards finding a solution to one of the critical but unsolved fusion plasma physics problems, which is to mitigate or suppress the potentially ...

Recommended for you

Quantum internet goes hybrid

November 22, 2017

In a recent study published in Nature, ICFO researchers led by ICREA Prof. Hugues de Riedmatten report an elementary "hybrid" quantum network link and demonstrate photonic quantum communication between two distinct quantum ...

Enhancing the quantum sensing capabilities of diamond

November 22, 2017

Researchers have discovered that dense ensembles of quantum spins can be created in diamond with high resolution using an electron microscopes, paving the way for enhanced sensors and resources for quantum technologies.

Study shows how to get sprayed metal coatings to stick

November 21, 2017

When bonding two pieces of metal, either the metals must melt a bit where they meet or some molten metal must be introduced between the pieces. A solid bond then forms when the metal solidifies again. But researchers at MIT ...

Imaging technique unlocks the secrets of 17th century artists

November 21, 2017

The secrets of 17th century artists can now be revealed, thanks to 21st century signal processing. Using modern high-speed scanners and the advanced signal processing techniques, researchers at the Georgia Institute of Technology ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.