1998/09/25 by Steven A. Balbus, Massimo Ricotti · 1 citation
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics and Star Formation Studies #Field line #Line (geometry) #Line of force #Lorentz force #Magnetic field #Magnetohydrodynamic drive #Magnetohydrodynamics #Plane (geometry) #Stellar, planetary, and galactic studies #Streamlines, streaklines, and pathlines #astro-ph
paper · pdf · doi:10.1086/307309
10 pages, no figures, submitted to ApJ
arxiv created 1998/09/25 · openalex publication_date 1999/06/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
A new class of disk MHD equilibrium solutions is described, which is valid within the standard local (shearing sheet) approximation scheme. These solutions have the following remarkable property: velocity streamlines and magnetic lines of force rotate rigidly, even in the presence of differential rotation. This situation comes about because the Lorentz forces acting upon modified epicycles compel fluid elements to follow magnetic lines of force. Field line (and streamline) configurations may be elliptical or hyperbolic, prograde or retrograde. These structures have previously known hydrodynamical analogs: the planet solutions described by Goodman, Narayan, & Goldreich. The primary focus of this investigation is configurations in the disk plane. A related family of solutions lying in a vertical plane is briefly discussed; other families of solutions may exist. Whether these MHD structures are stable is not yet known, but could readily be determined by three-dimensional simulations. If stable or quasi-stable, these simple structures may find important applications in both accretion and galactic disks.