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 Engineering team images tiny quasicrystals as they form
18.08.2017 | Cornell University

nachricht Astrophysicists explain the mysterious behavior of cosmic rays
18.08.2017 | Moscow Institute of Physics and Technology

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: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Nagoya physicists resolve long-standing mystery of structure-less transition

21.08.2017 | Materials Sciences

Chronic stress induces fatal organ dysfunctions via a new neural circuit

21.08.2017 | Health and Medicine

Scientists from the MSU studied new liquid-crystalline photochrom

21.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>