  We investigate the strong-field dynamics of a paramagnetic two-band Mott
insulator using real-time dynamical mean-field theory. A dielectric breakdown
occurs due to many-body Landau-Zener tunnelling, with a threshold field
determined by the gap. For a large range of fields, however, we predict that
the tunnelling currents are small enough to allow the observation of
field-induced localization of electrons, which becomes most strikingly evident
in atomic-like local spin multiplets determined by the Hund's coupling $J$.
This field-induced localization might provide a way of measuring the value of
$J$ in correlated materials. It should be observable in transition metal oxides
using time-resolved photo-emission spectroscopy or optical measurements in the
presence of strong THz field transients.
