  Non-thermal emission from Active Galactic Nuclei (AGN) jets extends up-to
large scales in-spite of them being prone to a slew of magneto-hydrodynamic
instabilities. The main focus of this study is to understand the impact of MHD
instabilities on the non-thermal emission from large-scale AGN jets. We perform
high-resolution three-dimensional numerical magneto-hydrodynamic simulations of
a plasma column to investigate the dynamical and emission properties of jet
configurations at kilo-parsec scales with different magnetic field profiles,
jet speeds, and density contrast. We also obtain synthetic non-thermal emission
signatures for different viewing angles using an approach that assumes static
particle spectra and that obtained by evolving the particle spectra using
Lagrangian macro-particles incorporating the effects of shock acceleration and
radiative losses. We find that the shocks due to Kelvin-Helmholtz (KH)
instability in the axial magnetic field configurations can strongly affect the
jet dynamics. Additionally, we also find the presence of weak biconical shocks
in the under-dense jet columns. The inclusion of a helical magnetic field
hinders the vortex growth at the shear surface thereby stabilizing the jet
column. With the evolving particle spectra approach, the synthetic SEDs
obtained for cases with strong KH instability show the presence of multiple
humps ranging from radio to TeV gamma-ray band. We conclude that the
high-energy electrons accelerated in the vicinity of freshly formed shocks due
to KH instability, result in high X-ray emission.
