Press releases
Please quote Nature Physics as the source of these items.
The May 2006 issue of Nature Physics is available online.
May 2006
Weather really is universal
The onset of intense tropical rain and magnetism share the same underlying physics, report Ole Peters and David Neelin in the June issue of Nature Physics. They describe a link between the physics of the two, even though magnetism has a lot of exact theoretical machinery behind it and no one can predict tomorrow's weather.
This is an example of universality, a property that enables different physical systems – with vastly different length-scales – to behave in similar ways near a phase transition.
The authors analysed the vapour content of tropical precipitation, or wet weather data, and found that it undergoes a smooth, continuous phase transition to a state of intense downpour as the amount of water vapour passes a critical value. This observed long-range correlated behaviour in atmospheric convection, of up to hundreds of kilometres, is similar to that well known in magnetic micrometre-scale crystals. That such simplicity lies behind a complex meteorological system is unexpected, and may pave the way for future climate models.
Critical phenomena in atmospheric precipitation
Ole Peters and J. David Neelin
Published online: 28 May 2006 | doi 10.1038/nphys314
Solution to fusion hurdle demonstrated
A solution to the problem of plasma instabilities that could threaten the commercial viability of fusion power is demonstrated by Todd Evans and colleagues in the June issue of Nature Physics. The work improves the chances for the success of ITER, the international experimental fusion reactor, which will be the next step towards harnessing the process that powers the sun as a clean, renewable source of energy.
ITER will work by heating a hydrogen plasma to more than 100 million degrees celsius — which causes the ions to fuse and release energy — while using a combination of magnetic fields to confine it within a doughnut–shaped chamber. It is feared that plasma instabilities, which cause lightning–like discharges of high–energy ions and eat away the inner walls of smaller fusion devices, could severely limit ITER's operation. But by weakly perturbing the magnetic field that confines the plasma in a way that causes the field lines at the edge to become chaotic, the authors show that these instabilities can be completely eliminated.
As well as improving the outlook for ITER — whose construction is due to begin later this year — the elimination of the wall–eroding instabilities will enable researchers to tackle other challenges that will face ITER's operation ahead of its scheduled completion in ten years time.
Edge stability and transport control with resonant magnetic perturbations in collisionless tokamak plasmas
Todd E. Evans, Richard A. Moyer, Keith H. Burrell, Max E. Fenstermacher, Ilon Joseph, Anthony W. Leonard, Thomas H. Osborne, Gary D. Porter, Michael J. Schaffer, Philip B. Snyder, Paul R. Thomas, Jonathan G. Watkins and William P. West
Published online: 21 May 2006 | doi 10.1038/nphys312