The Quadrupole Trap

• A quadrupole is simply the sum of two dipoles.

  • Dipole moving through a magnetized plasma, heliosphere, magnetosphere, galactosphere
  • A binary system of magnetized objects –binary stars
  • A distributed current system-Earth’s core, supernovae

• Quadrupoles have “null-points” which stably trap charged particles (eg. Paul trap used in atomic physics)

• Maxwell showed that a perfect conducting plane would “reflect” a dipole & form a quadrupole