  We discuss the coupling of the motion of two ion species in separate Penning
traps via a common tank circuit. The enhancement of the coupling assisted by
the tank circuit is demonstrated by an avoided crossing behavior measurement of
the motional modes of two coupled ions. We propose an intermittent laser
cooling method for sympathetic cooling and provide a theoretical description.
The technique enables tuning of the coupling strength between two ion species
in separate traps and thus allows for efficient sympathetic cooling of an
arbitrary type of single ion for high-precision Penning-trap experiments.
