Generalized Beltrami field modeling disk‐jet system

A generalized Beltrami field, including the effect of inhomogeneous density, can model the singular structure of thin‐disk and collimated‐jet combination. On an accretion disk, the singularity at the origin (r = 0) of the Keplerian rotation (Vθ∝r−1/2) is the determinant of the geometry and mechanics of accompanying jet: the collimation of the jet is the consequence of the alignment —so‐called Beltrami condition— of the flow velocity and the “generalized vorticity” that appears as an axle penetrating the disk (the vorticity is generalized to combine with magnetic field as well as to subtract the friction force causing the accretion). We construct an analytical solution of the simplified version of the model by the method of similarity solution.