(area around an object where its magnetic field dominates)
A magnetosphere is an area around an astronomical object
where the object's magnetic field dominates
the motion of charged particles.
For example, the Earth's magnetosphere
extends on the order of ten Earth diameters from Earth.
The Sun's extends past Pluto.
A magnetopause is the outer boundary of a magnetosphere,
commonly with a bow shock somewhat beyond it.
Beyond Earth's magnetopause is the solar wind.