“A MAGNETOSPHERE is a cavity in the solar wind flow formed by the interaction of the solar wind and interplanetary magnetic field with the intrinsic magnetic field or ionized upper atmosphere of a planetary body. In the terrestrial case, the interaction is dominated by the strong intrinsic quasidipolar magnetic field; this is also the case of the outer giant planets Jupiter, Saturn, Uranus and Neptune.”
https://link.springer.com/article/10.12942/lrsp-2007-1