sentences:  The term ‘electrostatic shock’ in the magnetosphere has been applied to electric fields oriented at an oblique angle to the magnetic field in such a way that the perpendicular electric field is much stronger than the parallel electric field, In laser physics, a double layer is sometimes called an ambipolar electric field.Double layers are conceptually related to the concept of a 'sheath' ("see" Debye sheath).An early review of double layers from laboratory experiment and simulations is provided by Torvén.