Larmor's theorem

Larmor's theorem [′lär·mȯrz ‚thir·əm]

(electromagnetism)

The theorem that for a system of charged particles, all having the same ratio of charge to mass, moving in a central field of force, the motion in a uniform magnetic inductionBis, to first order inB, the same as a possible motion in the absence ofBexcept for the superposition of a common precession of angular frequency equal to the Larmor frequency.