Contribution of the magnetic moment to the relativistic radiation reaction force.

Starting with the magnetic Smirnov reaction force, a relativistic equation which describes the motion of a charged particle with constant magnetic moment of spin , is obtained. A Landau?Lifshitz?like equation is deduced with magnetic moment. A fundamental difference between the classical and relativistic radiation rate of energy is found. It is shown that a quantum non-relativistic particle experiences a radiation friction force due to the interaction of its spin magnetic moment with a black body radiation thermal bath. The effect of spin precession in an external magnetic field on deceleration of the particle is considered.