Since the distance between the Zeeman sub-levels is a function of the magnetic field, this effect can be used to measure the magnetic field, e.g. that of the Sun and other stars or in laboratory plasmas.
Charley horse: Slang for a cramp in a muscle in the leg, usually caused by a strain or injury. A charley horse can last anywhere from a few seconds to over a quarter of an hour. It is not uncommon for one to recur before it finally resolves.
charley-horse - a muscular cramp (especially in the thigh or calf) following vigorous exercise. charley horse. colloquialism - a colloquial expression; characteristic of spoken or written communication that seeks to imitate informal speech. cramp, muscle spasm, spasm - a painful and involuntary muscular contraction.