Subscribe options

Select your newsletters:

Please enter your email address:

@

Your email address will only be used for the purpose of sending you the ITER Organization publication(s) that you have requested. ITER Organization will not transfer your email address or other personal data to any other party or use it for commercial purposes.

If you change your mind, you can easily unsubscribe by clicking the unsubscribe option at the bottom of an email you've received from ITER Organization.

For more information, see our Privacy policy.

News & Media

Latest ITER Newsline

  • Image of the week | First cryopump expected in the coming months

    The cryopumps that will create and maintain extremely demanding vacuum conditions inside the ITER machine are marvels of technology that have been in developmen [...]

    Read more

  • ITER Baseline | STAC committee reviews new plans for construction and operation

    Last week, the ITER Council Science and Technology Advisory Committee (STAC) met at ITER Headquarters to review the new plans for construction and operation pro [...]

    Read more

  • IAEA General Conference | Fusion energy strongly advocated

    Last week the International Atomic Energy Agency (IAEA) held its annual General Conference, with delegates representing more than 130 countries and many interna [...]

    Read more

  • On site | 28 who "truly shined"

    The new ITER Star Awards recognize exemplary performance and commitment. Every year, during the annual assessment campaign, ITER staff may be recognized for exe [...]

    Read more

  • MT-28 Conference | Superconducting magnets as a catalyst

    Many passers-by paused for a moment and picked up their cell phones to capture the scene. It was indeed rare to see dancers on the square outside of the Pavillo [...]

    Read more

Of Interest

See archived entries

A predator-prey relationship in the plasma jungle

Data from the TJ-II stellarator showing oscillations in the turbulence, slightly ahead of oscillations in the flow. (Click to view larger version...)
Data from the TJ-II stellarator showing oscillations in the turbulence, slightly ahead of oscillations in the flow.
There is a predator on the loose in Madrid. It's been discovered in the fusion laboratories of CIEMAT, preying on its favourite victim ... Turbulence!

This predator is not a large feline, but a type of plasma behaviour known as zonal flows. Strangely enough the relationship between zonal flows and turbulence follows exactly the same pattern as that between the numbers of predators and their prey in the wild—a significant discovery for fusion scientists in the quest to control the turbulence that allows energy to escape from their experiments.

In the same way that a large number of prey—for example, deer—might support an increasing population of tigers, in certain conditions turbulence seems to trigger the growth of the zonal flow pattern.

However as they grow, the zonal flows inhibit the turbulence, which dies away, eventually undermining the zonal flows, in the same way as a large population of tigers would cause a decline in the deer population, leading to their own downfall. But as the tiger population drops, the deer begin to thrive again, and so the cycle begins anew. This oscillatory predator-prey relationship is exactly what has been measured in the TJ-II stellarator at CIEMAT, as shown in the figure.

The scientist who made the discovery is Dr Teresa Estrada, head of microwave and laser diagnostics at TJ-II. "It was a lucky discovery!" she said. "I was not looking for this, the timescale of the oscillations is milliseconds so I could easily have missed it. I saw [the oscillations] first in the turbulence, and so I looked at the flow and was excited to see them there too, with the characteristic ninety degree phase delay."

Read more on the EFDA website.


return to the latest published articles