Taming 900 vortices gives plasma energy insight

Jan 05, 2007
Vortices created by the ANU physicists turbulence experiment
Vortices created by the ANU physicists turbulence experiment.

ANU researchers have come closer to understanding how energy is retained in turbulent systems that self-organise - such as the atmosphere, the universe and plasma - after designing a simple experiment in their laboratory which creates 900 vortices in electrolytic fluid.

The researchers watched as the 900 mini-vortices ‘self-organised’ to form one giant vortex. At this high energy state, the fluid developed powerful regions of ‘zonal flow’ which in turn created transport barriers – the key to reducing energy loss from the fluid.

The finding is particularly exciting for the study of turbulence in plasma - a hot, ionised gas - which is known to self-organise to a high energy state. The loss of energy from confined plasma has been one of the main challenges to making it a source of energy.

A better understanding of how this loss occurs has significant implications for the future of plasma energy sources, such as plasma fusion energy reactors, according to Dr Michael Shats, from the Research School of Physical Sciences and Engineering at ANU.

“From this experiment we’ve shown that this process of self-organisation works very similarly in a tank of fluid in the lab and in plasma at temperatures of millions of degrees – it opens up new avenues of discovery.”

In their latest paper published in the journal Physical Review Letters, Dr Shats and colleagues Dr Hua Xia and Dr Horst Punzmann detail how the powerful zonal flows that create the transport barriers, which in turn restrict the loss of energy from the system, are the result of turbulence self-organisation in plasma.

“When the plasma confined by a magnetic field reaches the high energy point of self-organisation, a zonal flow is generated. These zonal flows produce regions in the plasma known as transport barriers, which stop the loss of particles and energy out of the plasma system,” Dr Shats said.

In the natural world, there are already examples of these powerful flows. The turbulent water flow around the Antarctic continent prevents the freezing waters from escaping north, preserving the ice cap on one side and the tropical water on the other. “This is very similar to the transport barrier that we find in plasma,” Dr Shats said.

“Another example is the zonal flows in the atmospheres of most of the planets in the Solar System. High energy winds around Saturn exceed 1500 kilometres an hour. On Venus, zonal winds measure up to 400 kilometres an hour, which is much faster than the planet’s rotation velocity.

“These phenomena have common physics principles which can be studied in the lab, through experiments like ours, opening up a new research direction which will contribute to several fields ranging from improvement in the plasma confinement in a fusion reactor to a better understanding of atmospheric physics,” Dr Shats said.

Source: Australian National University

Explore further: And so they beat on, flagella against the cantilever

add to favorites email to friend print save as pdf

Related Stories

Recommended for you

And so they beat on, flagella against the cantilever

Sep 16, 2014

A team of researchers at Boston University and Stanford University School of Medicine has developed a new model to study the motion patterns of bacteria in real time and to determine how these motions relate ...

Tandem microwave destroys hazmat, disinfects

Sep 16, 2014

Dangerous materials can be destroyed, bacteria spores can be disinfected, and information can be collected that reveals the country of origin of radiological isotopes - all of this due to a commercial microwave ...

Cornell theorists continue the search for supersymmetry

Sep 16, 2014

(Phys.org) —It was a breakthrough with profound implications for the world as we know it: the Higgs boson, the elementary particle that gives all other particles their mass, discovered at the Large Hadron ...

How did evolution optimize circadian clocks?

Sep 12, 2014

(Phys.org) —From cyanobacteria to humans, many terrestrial species have acquired circadian rhythms that adapt to sunlight in order to increase survival rates. Studies have shown that the circadian clocks ...

User comments : 0