ABSTRACT
This chapter is devoted mainly to the description and theoretical interpretation of super-radiance experiments in a multi-proton spin system. It considers the simplest case of multi-spin super-radiance in a cavity. The spin magnetic moment in a static magnetic field is a perfect realization of the 'two-level' atomic model. In fact, this physical system was the origin of this model, and was extended to a wide class of resonant phenomena, including super-radiance. A refined description of super-radiance of magnetic spins in solids will probably have to take into account the dependence of the relaxation rate on the magnitude of the magnetization, using as a basis the concept of spin temperature. The chapter shows the limitations of the method of Bloch equations for describing NMR effects in solids, as mentioned earlier in the literature. It attempts to observe super-radiance in the radiofrequency domain was reported by P. Bosiger and their group, using a nuclear subsystem of Al atoms in ruby crystals.
