The Role of the Disk Magnetization in the Production of Jets

Abstract In this paper, we present results from a semi-analytical model that investigates the launching of cold, non-relativistic jets from a wide radial extent of stationary and axisymmetric magnetized accretion disks. Specifically, we examine the effects of magnetization on the disk-jet system in configurations where the magnetic field is near equipartition with the thermal pressure at the disk midplane. In this study, the magnetic strength parameter μ is explicitly expressed as a function of the magnetic diffusivity parameter α m ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>μ</mml:mi> <mml:mo>∼</mml:mo> <mml:mn>1</mml:mn> <mml:mo>/</mml:mo> <mml:msqrt> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>α</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>m</mml:mi> </mml:mrow> </mml:msub> </mml:mrow> </mml:msqrt> </mml:math> ). This formulation provides a more direct link between the magnetic field configuration and the diffusive processes within the accretion disk. By establishing this relationship, we better constrain the role of magnetization in jet launching and explore how variations in μ influence the overall disk-jet dynamics. We focus on three representative cases where μ takes the values 0.5, 0.7, and 0.9. We solve the stiff ordinary differential equations of the semi-analytical MHD model using the Seulex subroutine of Hairer &amp; Wanner, which employs the Taylor method with adaptive mesh refinement. The resulting solutions are compared with those obtained by Zanni et al., Tzeferacos et al., and Stepanovs &amp; Fendt.