Original URL: http://www.theregister.co.uk/2006/06/27/space_weather/

Solar simulation right on the money

Expect better space weather forecasts

By Lucy Sherriff

Posted in Science, 27th June 2006 10:14 GMT

California scientists have for the first time created a computer simulation that can accurately model the solar corona, or outer atmosphere of the sun.

The researchers at Science Applications International say the breakthrough should lead to dramatic improvements in the accuracy of space weather forecasts, helping scientists better predict the events on the sun's surface that affect the infrastructure on Earth.

Simulations of the corona's behaviour could give scientists clues about when the sun will produce flares, or coronal mass ejections, the researchers say. These huge ejections of solar plasma have a direct impact on orbiting satellites and land-based power and communications systems.

Simulations and reality

The research team used the model to simulate solar activity during an eclipse period, and produced two sets of simulated photographs of the eclipse before the 29 March event. As the images above show, the actual eclipse matched the predictions very closely, although the fine detail is missing (the left and centre images are the simulations, while the right-most image is an actual photograph of the corona, taken during the eclipse).

Previous simulations of the corona have been based on very simplified models of the corona. This new simulation, funded by NASA and the National Science Foundation, is rooted in the physics of how energy is transferred in the corona.

It is based on satellite observations of the corona, and the magnetic activity in the sun that shapes it, taken from the Solar and Heliospheric Observatory. This makes the calculations much more time-intensive (it took 700 computer processors four days to produce the simulated images), but far more accurate.

The corona is very faint relative to the main body of the sun. Without specialist equipment, it can only be seen during a total solar eclipse when the moon blocks most of the sun's direct light. ®