Magnetoconvection dynamics in a stratified layer. 1: Two-dimensional simulations and visualization

Abstract

view Abstract Citations (15) References (50) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Magnetoconvection Dynamics in a Stratified Layer. I. Two-dimensional Simulations and Visualization Lantz, Steven R. ; Sudan, R. N. Abstract To gain insight in the problem of fluid convection below solar photosphere, time-dependent magnetohydrodynamic convection is studied by numerical simulation to the magneto-anelastic equations, a model appropiate for low Mach numbers. Numerical solutions to the equations are generated on a two-dimensional Cartesian mesh by a finite-difference, predictor-corrector algorithm. The thermodynamic properties of the fluid are held constant at the rigid, stress-free top and bottom boundaries of the computational box, while lateral boundaries are treated as periodic. In most runs the background polytropic fluid configuration is held fixed at Rayleigh number R = 5.44 times the critical value, Prandtl number P = 1.8, and aspect ratio a = 1, while the magnetic parameters are allowed to vary. The resulting dynamical behavior is shown to be strongly influenced by a horizontal magnetic field which is imposed at the bottom boundary. As the field strength increases from zero, an initially unsteady 'single-roll' state, featuring complex time dependence is replaced by a steady 'traveling-wave tilted state; then, an oscillatory or 'sloshing' state; then, a steady two-poll state with no tilting; and finally, a stationary state. Because the magnetic field is matched onto a potential field at the top boundary, it can penetrate into the nonconducting region above. By varying a magnetic diffusivity, the concentrations of weak magnetic fields at the top of these flows can be shown to be explainable in terms of an advection-diffusion balance. Publication: The Astrophysical Journal Pub Date: March 1995 DOI: 10.1086/175411 Bibcode: 1995ApJ...441..903L Keywords: Magnetohydrodynamics; Solar Convection (Astronomy); Solar Interior; Solar Magnetic Field; Two Dimensional Models; Advection; Computerized Simulation; Diffusion; Finite Difference Theory; Magnetostriction; Predictor-Corrector Methods; Solar Physics; CONVECTION; MAGNETOHYDRODYNAMICS: MHD; SUN: INTERIOR; SUN: MAGNETIC FIELDS; VIDEOTAPES full text sources ADS | Related Materials (1) Part 2: 1995ApJ...441..925L