2006/10/20 by Jeffrey M. Anderson, Zhi-Yun Li, Zhi‐Yun Li +3 · 2 citations
Physics and Astronomy · #Astrophysics and Star Formation Studies #Classical mechanics #Field (mathematics) #Field line #Instability #Ionosphere and magnetosphere dynamics #Magnetic field #Magnetohydrodynamics #Mechanics #Physics #Rotational symmetry #Solar and Space Plasma Dynamics #Steady state (chemistry) #astro-ph
paper · pdf · doi:10.1086/510307
published as Astrophys.J.653:L33-L36,2006 · 10 pages, 2 figures, accepted for publication in ApJL
arxiv created 2006/10/20 · openalex publication_date 2006/11/27 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Outflows can be loaded and accelerated to high speeds along rapidly rotating, open magnetic field lines by centrifugal forces. Whether such magnetocentrifugally driven winds are stable is a long-standing theoretical problem. As a step toward addressing this problem, we perform the first large-scale 3D MHD simulations that extend to a distance ~10 2 times beyond the launching region, starting from steady 2D (axisymmetric) solutions. In an attempt to drive the wind unstable, we increase the mass loading on one half of the launching surface by a factor of and reduce it by the same factor on the other half. The evolution of the perturbed wind is followed numerically. We find no evidence for any rapidly growing instability that could disrupt the wind during the launching and initial phase of propagation, even when the magnetic field of the magnetocentrifugal wind is toroidally dominated all the way to the launching surface. The strongly perturbed wind settles into a new steady state, with a highly asymmetric mass distribution. The distribution of magnetic field strength is, in contrast, much more symmetric. We discuss possible reasons for the apparent stability, including stabilization by an axial poloidal magnetic field, which is required to bend field lines away from the vertical direction and produce a magnetocentrifugal wind in the first place.