Spin diffusion in inhomogeneous magnetic fields

Zubarev's nonequitibrium statistical operator method is used to obtain a diffusion equation for the energies of the Zeeman subsystem and the dipole-dipole reservoir in the case of inhomogeneous broadening due to an inhomogeneous magnetic field. Such a situation is realized in experiments in which relaxation of the nuclear magnetization is observed in superconductors of type II.