Published online by Cambridge University Press: 19 July 2016
We present preliminary results of 2D axisymmetric relativistic MHD simulations of PWNe, aimed at investigating whether structures such as the rings and jets revealed by high resolution X-ray imaging can be due to anisotropy of the outflow from the pulsar. We confirm that these features can qualitatively be explained when the energy flux is larger in the equatorial plane than along the spin axis. Detailed comparison between simulation results and observations is required to constrain the wind energy distribution upstream of the termination shock.