Sextupole magnet

The design of sextupoles using electromagnets generally involves six steel pole tips of alternating polarity.

The steel is magnetised by a large electric current that flows in the coils of wire wrapped around the poles.

Sextupolar fields have a focal length that is inversely proportional to the distance from the center of the magnet with which the particle passes.

This is similar to the action of a quadrupole, whose effect on the beam may be described as a bending whose strength depends on the distance from the center of the magnet.

This leads to equations of motion that cannot be solved for the general case, thus requiring approximations to be used when calculating their effects on the beam.

Sextupole electromagnet as used within the storage ring of the Australian Synchrotron to correct chromatic aberrations of the electron beam
Field lines of an idealized sextupole magnet in the plane transverse to the beam direction