  We investigate the emergence of amplitude and frequency chimera states in
ring-star networks consisting of identical Chua circuits connected via nonlocal
diffusive, bidirectional coupling. We first identify single-well chimera
patterns in a ring network under nonlocal coupling schemes. When a central node
is added to the network, forming a ring-star network, the central node acts as
the distributor of information, increasing the chances of synchronization.
Numerical simulations show that the radial coupling strength $k$ between the
central and the peripheral nodes acts as an order parameter leading from a
lower to a higher frequency domain. The transition between the domains takes
place for intermediate coupling values, $0.5 <k< 2$, where the frequency
chimera states prevail. The transition region (width and boundaries) depends on
the Chua oscillator parameters and the network specifics. Potential
applications of star connectivity can be found in the control of Chua networks
and in other coupled chaotic dynamical systems. By adding one central node and
without further modifications to the individual network parameters it is
possible to entrain the system to lower or higher frequency domains as desired
by the particular applications.
