  We apply magnetohydrodynamic (MHD) modeling to the radio galaxy Hercules A
for investigating the jet-driven shock, jet/lobe transition, wiggling, and
magnetic field distribution associated with this source. The model consists of
magnetic tower jets in a galaxy cluster environment, which has been discussed
in a series of our papers. The profile of underlying ambient gas plays an
important role in jet-lobe morphology. The balance between the magnetic
pressure generated by axial current and the ambient gas pressure can determine
the lobe radius. The jet body is confined jointly by the external pressure and
gravity inside the cluster core radius R_c, while outside R_c it expands
radially to form fat lobes in a steeply decreasing ambient thermal pressure
gradient. The current-carrying jets are responsible for generating a strong,
tightly wound helical magnetic field. This magnetic configuration will be
unstable against the current-driven kink mode and it visibly grows beyond R_c
where a separation between the jet forward and return currents occurs. The
reversed pinch profile of global magnetic field associated with the jet and
lobes produces projected B-vector distributions aligned with the jet flow and
the lobe edge. AGN-driven shock powered by the expanding magnetic tower jet
surrounds the jet/lobe structure and heats the ambient ICM. The lobes expand
subsonically; no obvious hot spots are produced at the heads of lobes. Several
key features in our MHD modeling may be qualitatively supported by the
observations of Hercules A.
