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Wednesday, July 10, 2013


As it slowly empties, the plasmasphere is filled by material from the underlying ionosphere. As such, the plasmaspheric wind plays an important role in atmospheric escape. Previously, transport of material out of the plasmasphere had only been observed in extreme conditions, when the Earth's magnetic field was disrupted by energetic particles coming from the Sun.

Measurements of this elusive space wind were obtained by the Cluster Ion Spectrometry experiment using the highly sensitive instrumentation aboard the four orbiting Cluster II spacecraft. "We now have experimental evidence that the plasmasphere is not in an equilibrium state, even during periods without geomagnetic storms," says physicist Iannis Dandouras, from the Centre National de la Recherche Scientifique (CNRS) and the University of Toulouse, France. He told that "The plasmasphere continuously blows out a weak but steady wind, supplying ionized material to the outer magnetosphere."