  Kink instabilities are likely to occur in the current-carrying magnetized
plasma jets. Recent observations of the blazar radiation and polarization
signatures suggest that the blazar emission region may be considerably
magnetized. While the kink instability has been studied with first-principle
magnetohydrodynamic (MHD) simulations, the corresponding time-dependent
radiation and polarization signatures have not been investigated. In this
paper, we perform comprehensive polarization-dependent radiation modeling of
the kink instability in the blazar emission region based on relativistic MHD
(RMHD) simulations. We find that the kink instability may give rise to strong
flares with polarization angle (PA) swings or weak flares with polarization
fluctuations, depending on the initial magnetic topology and magnetization.
These findings are consistent with observations. Compared with the shock model,
the kink model generates polarization signatures that are in better agreement
with the general polarization observations. Therefore, we suggest that kink
instabilities may widely exist in the jet environment, and provide an efficient
way to convert the magnetic energy and produce multiwavelength flares and
polarization variations.
