  In this paper, we investigate the evolution of the plasmoid-chain in a
Poynting-dominated plasma. We model the relativistic current sheet with cold
background plasma using the relativistic resistive magnetohydrodynamic
approximation, and solve its temporal evolution numerically. We perform various
calculations using different magnetization parameters of the background plasma
and different Lundquist numbers. Numerical results show that the initially
induced plasmoid triggers a secondary tearing instability, which gradually
fills the current sheet with plasmoids, as has also been observed in the
non-relativistic case. We find the plasmoid-chain greatly enhances the
reconnection rate, which becomes independent of the Lundquist number, when this
exceeds a critical value. In addition, we show the distribution of plasmoid
size becomes a power law. Since magnetic reconnection is expected to play an
important role in various high energy astrophysical phenomena, our results can
be used for explaining the physical mechanism of them.
