A schematic drawing of the magnetopause surface as well as the magnetosphere and its various features is described. The magnetospheric field magnitude decreases with increasing with increasing distance from Earth, but less rapidly than a dipole field in a vacuum. The orientation of the magnetopause surface is of importance for the purpose of establishing whether there is a magnetic connection and associated plasma flow across this boundary. An important parameter is the thickness of the magnetopause, which determines the intensity of the currents in the layer and the steepness of the density gradients and velocities across it.