Stability and structure of analytical MHD jet formation models with a finite outer disk radius

TL;DR

This paper investigates how imposing a finite outer radius on analytical MHD jet models affects their structure, stability, and topology, addressing limitations of self-similar solutions through hybrid initial conditions.

Contribution

It introduces a method to incorporate a finite outer disk radius into analytical MHD jet models, producing steady two-component solutions and improving physical realism.

Findings

Finite outer radius influences jet topology and stability.

Hybrid initial conditions lead to steady two-component solutions.

The approach mitigates singularities of self-similar models.

Abstract

(Abridged) Finite radius accretion disks are a strong candidate for launching astrophysical jets from their inner parts and disk-winds are considered as the basic component of such magnetically collimated outflows. The only available analytical MHD solutions for describing disk-driven jets are those characterized by the symmetry of radial self-similarity. Radially self-similar MHD models, in general, have two geometrical shortcomings, a singularity at the jet axis and the non-existence of an intrinsic radial scale, i.e. the jets formally extend to radial infinity. Hence, numerical simulations are necessary to extend the analytical solutions towards the axis and impose a physical boundary at finite radial distance. We focus here on studying the effects of imposing an outer radius of the underlying accreting disk (and thus also of the outflow) on the topology, structure and variability of a radially self-similar analytical MHD solution. The initial condition consists of a hybrid of an unchanged and a scaled-down analytical solution, one for the jet and the other for its environment. In all studied cases, we find at the end steady two-component solutions.