Speaker
Description
Magnetars are young, isolated neutron stars that possess exceptionally high magnetic fields. To explain their formation, one plausible scenario relies on a turbulent convective dynamo that develops inside the protoneutron star. However, the short expected duration of the convection phase imposes a stringent constraint on the efficiency of amplification process. We address this question by combining high-performance direct numerical simulations and statistical small-scale dynamo models to investigate kinematic dynamos. We find that the typical growth rate is of the order of 1/ms in the limit of large magnetic Prandtl number. These results thus suggest that a convective dynamo is efficient enough to generate small-scale magnetic fields of magnetar strength in about 10 seconds, but they do not address the generation of the large-scale dipole field which may occur during the saturation phase.