Notes

• NOTE 1 It is also referred as L, and is used as a co-ordinate to describe positions in near-Earth space.
• NOTE 2 L or L shell has a complicated derivation based on an invariant of the motion of charged particles in the terrestrial magnetic field. However, it is useful in defining plasma regimes within the magnetosphere because, for a dipole magnetic field, it is equal to the geocentric altitude in Earth-radii of the local magnetic field line where it crosses the equator.