  Superradiance is the effect of field waves being amplified during reflection
from a charged or rotating black hole. In this paper, we study the low-energy
dynamics of super-radiant scattering of massive scalar and massless higher spin
field perturbations in a generic axisymmetric stationary Kerr-Taub-NUT
(Newman-Unti-Tamburino) spacetime, which represents sources with both
gravitomagnetic monopole moment (magnetic mass) and gravitomagnetic dipole
moment (angular momentum). We obtain a generalized Teukolsky master equation
for all spin perturbation fields. The equations are separated into their
angular and radial parts. The angular equations lead to spin-weighted
spheroidal harmonic functions that generalize those in Kerr spacetime. We
identify an effective spin as a coupling between frequency (or energy) and the
NUT parameter. The behaviors of the radial wave function near the horizon and
at the infinite boundary are studied. We provide analytical expressions for
low-energy observables such as emission rates and cross sections of all
massless fields with spin, including scalar, neutrino, electromagnetic,
Rarita-Schwinger, and gravitational waves.
