The Source of Solar Wind Discovered

A team of scientists has found the source of the stream of particles that build the solar wind. At the RAS National Astronomy Meeting in Belfast, Professor Louise Harra explained how astronomers have used a UK-led instrument on Hinode space observatory to track down the starting point for the wind.

Solar wind consists of electrically charged particles that flow out from the Sun in all directions. The particles have a minimum speed of 200 km per second, taking 10 days to travel from the Sun to the Earth. These winds create the northern and southern lights auroras and can interfering with electronic systems on satellites and sometimes can overload electrical power grids on the ground.

Hinode was launched in the autumn of 2006 and since then it has been used to study the Sun. One of the instruments on the probe, the UK-built Extreme Ultraviolet Imaging Spectrometer (EIS) measures the speed at which material flows out from the Sun.

The Sun is shaped by magnetic fields, which create regions of high activity. Scientists found that at the edges of these regions hot gas spurts out at high speeds and that magnetic fields connect the regions together even if they are widely separated.