EXACT-SOLUTIONS FOR HELICAL MHD EQUILIBRIA OF ASTROPHYSICAL JETS

In the framework of the analytical study of helically symmetric magnetohydrodynamic (MHD) equilibria with non-uniform density, a novel, general family of well-behaved exact solutions of the generalized Grad-Shafranov equation is obtained. They are discussed in order to show their relevance to describe astrophysical jets. In this connection, cylindrically, axially and, especially, helically symmetric configurations are analyzed. In particular it is shown how a helical morphology of the kind of those observed in M87 and 3C 66B can arise from the helical solutions, corresponding to models in which a strong magnetic field is confined in one or more helical filaments winding at some distance from the axis of the jet.