Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Plasma doughnut currents made hollow, leading to greater efficiency for fusion


Computer simulation of the sequence of events in the reconnection process. Shown are contours of constant pressure at different times. As the current starts to become negative, the reconnection process begins and moves the center rapidly to the edge, effectively clamping the current in the center at zero

Doughnuts of plasma can be coaxed into configurations with hollow current rings, providing practical advantages over conventional “filled doughnut” shapes. Simulations suggest they will allow faster turn-on and greater efficiency of future nuclear fusion power plants.

Toroidal tokamaks, doughnut-shaped experimental fusion reactors, use a complex system of magnetic fields to hold a plasma together. Electrical currents flowing in the plasma itself are essential for making the internal magnetic fields needed for confinement. Plasma doughnuts normally carry large electrical currents throughout their volume but researchers expected the direction of the current could be changed back and forth.

However, in recent experiments at the Joint European Torus (JET) and JT-60U tokamaks in England and Japan, researchers tried to reverse the current and found, to their surprise, that the current doughnut became hollow.

Now computer simulations conducted by researchers at the DOE’s Princeton Plasma Physics Laboratory (PPPL) using supercomputers at the National Energy Research Supercomputer Center have explained this phenomenon. Instead of the electric current reversing direction, the plasma experiences magnetic reconnection (see Highlight 4) and the core becomes stabilized with zero current. As soon as a current tries to reverse in the center, it is pulled into the outer ring. (See images.) This new understanding should allow a more practical design of compact next-generation fusion experiments.

Joshua Breslau, PPPL, 609-243-2677,

David Harris | EurekAlert!
Further information:

More articles from Physics and Astronomy:

nachricht Taming chaos: Calculating probability in complex systems
21.03.2018 | American Institute of Physics

nachricht TRAPPIST-1 planets provide clues to the nature of habitable worlds
21.03.2018 | Arizona State University

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

Im Focus: Tiny implants for cells are functional in vivo

For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.

In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

Latest News

New 4-D printer could reshape the world we live in

21.03.2018 | Life Sciences

Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

21.03.2018 | Trade Fair News

Physicists made crystal lattice from polaritons

20.03.2018 | Physics and Astronomy

Science & Research
Overview of more VideoLinks >>>