Washington: A new study provides proof that space wind does exist, a theory which was first proposed 20 years ago.
By analysing data from the European Space Agency`s Cluster spacecraft, researcher Iannis Dandouras detected this plasmaspheric wind, so-called because it contributes to the loss of material from the plasmasphere, a donut-shaped region extending above the Earth`s atmosphere.
"After long scrutiny of the data, there it was, a slow but steady wind, releasing about 1 kg of plasma every second into the outer magnetosphere: this corresponds to almost 90 tonnes every day," Dandouras of the Research Institute in Astrophysics and Planetology in Toulouse, France, said.
The plasmasphere is a region filled with charged particles that takes up the inner part of the Earth`s magnetosphere, which is dominated by the planet`s magnetic field.
To detect the wind, Dandouras analysed the properties of these charged particles, using information collected in the plasmasphere by ESA`s Cluster spacecraft.
Further, he developed a filtering technique to eliminate noise sources and to look for plasma motion along the radial direction, either directed at the Earth or outer space.
As detailed in the study, the data showed a steady and persistent wind carrying about a kilo of the plasmasphere`s material outwards each second at a speed of over 5,000 km/h.
This plasma motion was present at all times, even when the Earth`s magnetic field was not being disturbed by energetic particles coming from the Sun.
The results are published in Annales Geophysicae, a journal of the European Geosciences Union (EGU).