Magnetic acceleration of ultra-relativistic GRB and AGN jets

Understand

We present numerical simulations of cold, axisymmetric, magnetically driven relativistic outflows.

• The outflows are initially sub-Alfv\'enic and Poynting flux-dominated, with total--to--rest-mass energy flux ratio up to $\mu \sim 620$.
• To study the magnetic acceleration of jets we simulate flows confined within a funnel with rigid wall of prescribed shape, which we take to be $z\propto r^a$ (in cylindrical coordinates, with $a$ ranging from 1 to 2).
• This allows us to eliminate the numerical dissipative effects induced by a free boundary with an ambient medium.