  We study driven atomic Josephson junctions realized by coupling two
two-dimensional atomic clouds with a tunneling barrier. By moving the barrier
at a constant velocity, dc and ac Josephson regimes are characterized by a zero
and nonzero atomic density difference across the junction, respectively. Here,
we monitor the dynamics resulting in the system when, in addition to the above
constant velocity protocol, the position of the barrier is periodically driven.
We demonstrate that the time-averaged particle imbalance features a step-like
behavior that is the analog of Shapiro steps observed in driven superconducting
Josephson junctions. The underlying dynamics reveals an intriguing interplay of
the vortex and phonon excitations, where Shapiro steps are induced via
suppression of vortex growth. We study the system with a classical-field
dynamics method, and benchmark our findings with a driven circuit dynamics.
