  We studied the dynamic response and stochastic resonance of kinetic Ising
spin system (ISS), subject to the joint external field of weak sinusoidal
modulation and stochastic white-noise, through solving the mean-field equation
of motion based on Glauber dynamics. The periodically driven stochastic ISS
shows the occurrence of characteristic stochastic resonance as well as
nonequilibrium dynamic phase transition (NDPT) when the frequency and amplitude
h0 of driving field, the temperature t of the system and noise intensity D
attain a specific accordance in quantity. There exist in the system two typical
dynamic phases, referred to as dynamic disordered paramagnetic and ordered
ferromagnetic phases respectively, corresponding to zero and unit dynamic order
parameter. We also figured out the NDPT boundary surface of the system which
separates the dynamic paramagnetic and dynamic ferromagnetic phase in the 3D
parameter space of h0~t~D. An intriguing dynamical ferromagnetic phase with an
intermediate order parameter at 0.66 was revealed for the first time in the ISS
subject to the perturbation of a joint determinant and stochastic field. Our
primary result indicates that the intermediate order dynamical ferromagnetic
phase is dynamic metastable in nature and owns a peculiar characteristic in its
stability and response to external driving field when compared with fully order
dynamic ferromagnetic phase.
