Fast polarization reversal of proton spins in solid-state targets

The method of polarization reversal of proton spins in solid-state targets, by using the effect of spin superradiance is analysed theoretically. The main aim is to find out the most accurate way of calculating the time of reversal and the final reversal polarization. Three approaches are compared: one, based on the standard Bloch equations; another, using numerical simulations for finite-particle model; and an approach based on effective equations taking into account local spin fluctuations. The latter method is shown to be the most accurate. The minimal reversal time can be of the order of 10−5 – 10−4 s. The maximal final polarization can reach 80–90%, but can never be 100% complete. The proposed method only works from negative to positive polarization.