In a first round of simulations we investigated situations described by model (B), an idealization of the experiments presented above. In order to ensure the presence of maser pulses in the simulations, we set the condition γ 2 /γ rd ≤ 1 at the initial time of the trajectory, when the magnitude of the total magnetization is largest. The latter was equal to the stationary hyperpolarized magnetization m st 0 , which was set to a negative value, as only a negative polarization is expected to lead multiple masers.