Drift of Circular Current Loop in Inhomogeneous Magnetic Field

The drift of particle guiding centre in inhomogeneous magnetic field is discussed by making use of the average magnetic force on an equivalent circular current loop,and a model for Larmor gyration of a charged particle.Consequently two drift speed components perpendicular to the magnetic field is presented through the way of three-dimensional vector arithmetic,including the familiar term of grad B drift and an extra drift term caused by▽×B,which will be helpful to realize the drift instability of the high temperature fusion in magnetic confinement.