Dipolar temperature and Multiple Quantum NMR Dynamics in Dipolar Ordered Spin Systems

We investigate analytically and numerically the Multiple Quantum (MQ) NMR dynamics in systems of nuclear spins $1/2$ coupled by the dipole-dipole interactions in the case of the dipolar ordered initial state. We suggest a new method of MQ NMR based on the measurement of the dipolar temperature in the quasi-equilibrium state which establishes after the time of order $\omega_{loc}^{-1}$ ($\omega_{loc}$ is the dipolar local field) after the MQ NMR experiment. Many-spin clusters and correlations are created faster in such experiment than in the usual MQ NMR experiments and can be used for the investigation of many-spin dynamics of nuclear spins in solids.