A Note on the Dipole Coordinates
  A couple of orthogonal coordinates for dipole geometry are proposed for numerical simulations of plasma geophysics in the Earth's dipole magnetic field. These coordinates have proper metric profiles along field lines in contrast to the standard dipole coordinate system that is commonly used in analytical studies for dipole geometry. 
Akira Kageyama, Tooru Sugiyama, Kunihiko Watanabe, Tetsuya Sato