This work is devoted to highlighting the diffusion of some models of Kinetic-Bloch system by an asymptotic analysis. The limit of the kinetic equation when using the classical diffusion scaling shows that the magnetization field becomes parallel to the magnetic field. For the limit of the magnetization when we use a second scaling of the kinetic equation, we show that the dynamics of the magnetization is driven by the Bloch-Torrey diffusion equation.
