Predicting the weather in space

At the British Association for the Advancement of Science meeting in Glasgow today, Dr Andrew Coates will unveil some of the new results from a year-long study for the satellite insurance industry, via the Tsunami initiative, on the effects of space weather on spacecraft. In particular a web-based prediction system has been developed to warn of potential danger for satellites, using a 'red/amber/green' traffic light system. This uses real measured conditions from spacecraft upstream of Earth's magnetic shield, to predict the amount of dangerous 'killer electrons' nearer to Earth over the following days. The team have found that conditions in the solar wind give the best hope for prediction of these potentially damaging particles. They are also developing a 'black box' detector for use on commercial spacecraft.

Space weather produces real problems for humankind and for space and ground-based technology although we are shielded from the charged particle onslaught by Earth's magnetic field. As well as heat and light, the Sun produces a million tonnes per second of solar wind on average. But the average picture does not always hold. Events called coronal mass ejections fling 10 billion tonnes of solar material into space, and some of these are directed at Earth. When they reach Earth, charged particles from these events penetrate Earth's magnetic shield and cause problems for power distribution systems, astronauts and satellites. In addition, solar flares can send particles towards us at speeds close to the velocity of light. These in turn can cause problems for satellites on which we increasingly rely for communications, weather forecasting and positioning. The 'killer electrons' in the Earth's environment are produced when particles entering from the solar wind are accelerated to relativistic energies becoming part of the radiation belts. The new predictions used by the web-based system are of when this process occurs. Other work in MSSL's space plasma group, which Dr Coates leads, examines why the acceleration happens

Dr Coates' talk ('What is space weather and why is it important?', to be given on 7 September at 1000 in Glasgow) is an introduction to space weather and its effects, part of a session at the BA meeting on space weather. New results from the Cluster spacecraft, which studies the science behind space weather, and illustrations of the causes and effects of space weather, will also be shown.

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