Magnetic field between the planetary surface and the substellar point of the magnetopause as a function of distance from the planetary center, relative to the field at the planetary surface. Thick solid line: pure planetary dipole. Curved blue line: case of a planet with a magnetic moment identical to that of the Earth (ℳ = 1.0 ℳ_⊕). Curved black lines: magnetic field for different magnetospheric configurations. Straight dotted line: 2.32 times the value for a pure planetary dipole (see text for details).