Cooling techniques are important for the control the
emittance of
particle beams in
particle accelerators. Usually, these techniques take advantage, in some way, of the electric or the magnetic fields present in the fast-moving bunches of particles in the accelerator in clever ways to damp the tendency of these particles to repel each other. It is accurate to think of these techniques as
thermodynamic , or the reduction of
entropy, in much the same way that a
refrigerator or an
air conditioner cools its contents.