News from the world of maths: Fractals in the Sun's storms

Plasma astrophysicists at the University of Warwick have found that key information about the Sun's "storm season" is being broadcast across the solar system in a fractal snapshot imprinted in the solar wind. This research opens up new ways of looking at both space weather and the unstable behaviour that affects the operation of fusion powered power plants.

Solar wind consists of a stream of plasma, mainly protons and electrons, that are ejected by the Sun's corona. On its way out the wind interacts with the Sun's magnetic field, broadcasting it across the universe. The researchers, led by Sandra Chapman, measured the strength of the magnetic field in the solar wind. They found that when the Sun is at the peak of its 11-year cycle, the graph they were plotting turned into a fractal. At this point the solar corona was at its most active, stormy and complex, due to sunspot activity, solar flares, etc. When the corona was quieter no fractal patterns were found in the solar wind.

This new information will help astrophysicists understand how the solar corona heats the solar wind and the nature of the turbulence of the solar wind with its implications for cosmic ray flux and space weather.

The techniques used to find and understand the fractal patterns in the solar wind are also being used to assist the quest for fusion power. Researchers in the University of Warwick's Centre for Fusion, Space and Astrophysics (CFSA) are collaborating with scientists from the EURATOM/UKAEA fusion research programme to measure and understand fluctuations in the world leading fusion experiment MAST (the Mega Amp Spherical Tokamak) at Culham. Controlling plasma fluctuations in tokamaks is important for getting the best performance out of future fusion power plants.

Find out more about fractals in Plus, and read more about fractal solar winds in New Scientist.