the outer region of the earth's ionosphere, where the earth's magnetic field controls the motion of charged particles, as in the Van Allen belts.Compare magnetopause.
such a region of another planet: Jupiter's magnetosphere.
Origin of magnetosphere
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the region surrounding a planet, such as the earth, in which the behaviour of charged particles is controlled by the planet's magnetic field
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Online Etymology Dictionary, © 2010 Douglas Harper
A highly asymmetrical region surrounding the Earth, beginning about 100 km (62 mi) above the surface on the side of the Earth facing the Sun and extending hundreds of thousands of kilometers into space on the opposite side. In this region the Earth's magnetic field exerts a significant influence on any charged particles that encounter it. The magnetosphere deflects most of the charged particles in the solar wind, but also traps and deflects some of these particles toward the Earth's magnetic poles, causing magnetic storms and auroras.
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