  Magneto-solid-mechanical model of two-component, core-crust, paramagnetic
neutron star responding to quake-induced perturbation by differentially
rotational, torsional, oscillations of crustal electron-nuclear solid-state
plasma about axis of magnetic field frozen in the immobile paramagnetic core is
developed. Particular attention is given to the node-free torsional
crust-against-core vibrations under combined action of Lorentz magnetic and
Hooke's elastic forces; the damping is attributed to Newtonian force of shear
viscose stresses in crustal solid-state plasma. The spectral formulae for the
frequency and lifetime of this toroidal mode are derived in analytic form and
discussed in the context of quasi-periodic oscillations of the X-ray outburst
flux from quaking magnetars. The application of obtained theoretical spectra to
modal analysis of available data on frequencies of oscillating outburst
emission suggests that detected variability is the manifestation of crustal
Alfven's seismic vibrations restored by Lorentz force of magnetic field
stresses.
