  Domain-walls in one-dimensional Ising ferromagnets can undergo Bloch
oscillations when subjected to a skew magnetic field. Such oscillations imply
finite temperature non-dispersive low-frequency peaks in the dynamical
structure factor which can be probed in neutron scattering. We study in detail
the spectral weight of these peaks. Using an analytical approach based on an
approximate treatment of a gas of spin-cluster excitations we give an explicit
expression for the momentum- and temperature-dependence of the spectral
weights. Generally the spectral weights increase with temperature and
approaches the same order of magnitude as the spin-wave spectral weights at
high temperatures. We compare the analytical expression to numerical exact
diagonalizations and find that it can, without any adjustable parameters,
account for the temperature and momentum-transfer dependence of the numerically
obtained spectral weights in the parameter regime where the ratio of magnetic
fields $h_x/h_z \ll 1$ and the temperature is $h_x < T <\sim J_z/2$. We also
carry out numerical calculations pertinent to the material CoNb$_2$O$_6$, and
find qualitatively similar results.
