quadrupole

From quadru- + pole.

quadrupole (plural quadrupoles)

1. (physics) A distribution of either electric charge or magnetization equivalent to two dipoles that point in opposite directions.
   • 1975, David M. Cook, The Theory of the Electromagnetic Field, page 123:

     Consider a linear quadrupole consisting of a point charge of strength 2q at the origin and point charges of strength —q at (0, 0, a) and (0, 0, —a).

2. (physics) A magnet with two north poles and two south poles, used to focus a beam of particles.

• quadrupolar
• octupole

• quadripole