Interaction of Fanaroff-Riley class II jets with a magnetised
  intra-cluster medium
  We present 3-D MHD and synthetic numerical simulations to follow the
evolution of randomly magnetized intra-cluster medium plasma under the effects
of powerful, light, hypersonic and bipolar jets. We prescribe the cluster
magnetic field (CMF) as a Gaussian random field with power law energy spectrum
tuned to the expectation for Kolmogorov turbulence. We investigate the power of
jets and the viewing angle used for the synthetic Rotation Measure (RM)
observations. We find the model radio sources introduce and amplify
fluctuations on the RM statistical properties; the average RM and the RM
standard deviation are increased by the action of the jets. This may lead to
overestimations of the CMFs' strength up to 70%. The effect correlates with the
jet power. Jets distort and amplify CMFs especially near the edges of the lobes
and the jets' heads. Thus the RM structure functions are flattened at scales
comparable to the source size. Jet-produced RM enhancements depend on the
orientation of the jet axis to the line of sight and are thus more apparent in
quasars than in radio galaxies.
