Current-driven instabilities in astrophysical jets Non linear development

The non linear development of instabilities driven by the presence of an electric current is investigated for magnetized jets using 3-dimensional MHD simulations. General magnetic equilibria for cold supermagnetosonic jets with constant velocity are considered in order to study the influence of the initial configuration on the non linear evolution. It is found that the current density is redistributed within the inner part of the jet radius with a characteristic time scale and an axial wavelength in agreement with the linear analysis. For equilibria having a pitch profile that increases with radius, an internal helical ribbon with a high current density is forming. It gives rise to considerable dissipation which is radially localized, and may result in heating and particle acceleration within the jet.