Small-scale dynamos on the solar surface: dependence on magnetic Prandtl number

摘要: The question of possible small-scale dynamo action in the surface layers Sun is revisited with realistic 3D MHD simulations. As other problems, found to be a sensitive function magnetic Prandtl number ${\rm P_{\rm m} }=\nu/\eta$; it disappears below critical value c}}$ which numerical resolution. At grid spacing 3.5 km, based on hyperdiffusivities implemented code (STAGGER) $\approx 1$, increasing spacing. settings, remains uncertain whether small scale present astrophysical limit where }<<1$ and Reynolds R_m}\gg 1$. discussed context strong effect that external stray fields are observed have generating maintaining laboratory systems, connection type-II hypertransient behavior absence such fields.