  Spin effects in above-threshold ionization of hydrogenlike highly charged
ions in super-strong laser fields are investigated. Spin-resolved ionization
rates in the tunneling regime are calculated by employing two versions of a
relativistic Coulomb-corrected strong-field approximation (SFA). An intuitive
simple-man model is developed which explains the derived scaling laws for
spin-flip and spin-asymmetry effects. The intuitive model as well as our ab
initio numerical simulations support the analytical results for the spin
effects obtained in the dressed SFA where the impact of the laser field on the
electron spin evolution in the bound state is taken into account. In contrast,
the standard SFA is shown to fail in reproducing spin effects at ionization
even at a qualitative level. The anticipated spin-effects are expected to be
measurable with modern laser techniques combined with an ion storage facility.
