Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Striking the right note on a magnetic violin

11.11.2015

Researchers learn to fine tune tokamak magnetic fields to mitigate damaging energy bursts

The swirling plasma in donut-shaped fusion facilities called tokamaks are subject to intense heat bursts that can damage the vessel's walls. Halting or mitigating these bursts, called Edge Localized Modes (ELMs), is a key goal of fusion research.


Researchers used the rectangular coils shown here to strike the magnetic fields that enclose the donut-shaped plasma. The colors of the plasma denote the different vibrations produced by striking the fields with external magnetic coils.

Figure courtesy of Princeton Plasma Physics Laboratory and General Atomics.

While physicists have long known that they could suppress ELMs by pushing and pulling on the plasma with magnetic fields, they frequently found that doing so destabilized the core of the plasma. The reason for this was that perturbing the plasma as they were doing always led to the same response, like producing the same note when striking a tuning fork.

Now scientists at General Atomics and the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL) have found an effective way to mitigate ELMs without adversely affecting plasma in the core region. They were able to do this because the magnetic fields that enclose the plasma are like the strings on a violin that produce notes when struck with the fields from external magnetic coils (Figure 1). And one of these notes, the researchers found, is particularly useful for preventing ELMs.

... more about:
»Atomics »ITER »PPPL »Plasma »magnetic fields »physics

They discovered this note by pushing and pulling the fields that encircle the tokamak for two rotations instead of the standard one during experiments on the DIII-D National Fusion Facility that General Atomics operates for the DOE in San Diego. This produced a very stable mode of response that can be used to help control the edge of the plasma.

The researchers verified these findings with diagnostics that showed the different plasma responses to the two-rotation perturbations. "We now understand how to pluck just the notes that sound the best, giving us the power to fine-tune our plasmas" says Nikolas Logan, who led the research team with Carlos Paz-Soldan of General Atomics and will give an invited talk on the results at the 57th Annual Meeting of the APS Division of Plasma Physics.

These finding could have important implications for ITER, the multinational tokamak being built in France. They suggest that ITER may be able to use the newly discovered results to prevent or mitigate ELMs without impacting overall performance.

###

Contact: Nikolas Logan, (858)-455-3614, nlogan@pppl.gov

Abstracts: BI2.00005 Observation, Identification, and Impact of Multi-Modal Plasma Responses to Applied Magnetic Perturbations
Session Session BI2: Pedestals
9:30 AM-12:30 PM, Monday, November 16, 2015
Room: Chatham Ballroom C

Media Contact

Saralyn Stewart
stewart@physics.utexas.edu
512-694-2320

 @APSphysics

http://www.aps.org 

Saralyn Stewart | EurekAlert!

Further reports about: Atomics ITER PPPL Plasma magnetic fields physics

More articles from Physics and Astronomy:

nachricht Computer model predicts how fracturing metallic glass releases energy at the atomic level
20.07.2018 | American Institute of Physics

nachricht What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin

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: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>