  We experimentally and theoretically characterize the temporal rotation and
radial twist of the interference pattern of vortex beam with its conjugate
copy. To quantitatively study the temporal rotation and radial twist, we
controllably modify the conjugate beam with a frequency or wavefront curvature
difference using a movable Mach-Zehnder interferometer. The effects of the
physical parameters (i.e., the topological charge, frequency difference and
wavefront curvature difference of the vortex beams) on the temporal rotation as
well as radial twist are systematically explored. We further measure two
parameters, the rotation velocity $\Omega$ and twist coefficient $\alpha$,
respectively, to characterize the degree of the temporal rotation and radial
twist of the interference pattern. The theory of the interference model on
vortex beams have good agreements with the experimental results. This work is
favorite to study the detailed structure of the interference pattern and
manipulate matter with superimposed vortex beams.
