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Title: CONNECTIONS BETWEEN LOCAL AND GLOBAL TURBULENCE IN ACCRETION DISKS

Abstract

We analyze a suite of global magnetohydrodynamic (MHD) accretion disk simulations in order to determine whether scaling laws for turbulence driven by the magnetorotational instability, discovered via local shearing-box studies, are globally robust. The simulations model geometrically thin disks with zero net magnetic flux and no explicit resistivity or viscosity. We show that the local Maxwell stress is correlated with the self-generated local vertical magnetic field in a manner that is similar to that found in local simulations. Moreover, local patches of vertical field are strong enough to stimulate and control the strength of angular momentum transport across much of the disk. We demonstrate the importance of magnetic linkages (through the low-density corona) between different regions of the disk in determining the local field, and suggest a new convergence requirement for global simulations-the vertical extent of the corona must be fully captured and resolved. Finally, we examine the temporal convergence of the average stress and show that an initial long-term secular drift in the local flux-stress relation dies away on a timescale that is consistent with turbulent mixing of the initial magnetic field.

Authors:
 [1];  [2];  [3]
  1. Department of Mathematics and Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States)
  2. Joint Space Science Institute (JSI), University of Maryland, College Park, MD 20742-2421 (United States)
  3. JILA, 440 UCB, University of Colorado, Boulder, CO 80309-0440 (United States)
Publication Date:
OSTI Identifier:
21394204
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 712; Journal Issue: 2; Other Information: DOI: 10.1088/0004-637X/712/2/1241; Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ACCRETION DISKS; ANGULAR MOMENTUM; CONVERGENCE; INSTABILITY; MAGNETIC FIELDS; MAGNETIC FLUX; MAGNETOHYDRODYNAMICS; SCALING LAWS; SIMULATION; STRESSES; TURBULENCE; FLUID MECHANICS; HYDRODYNAMICS; MECHANICS

Citation Formats

Sorathia, Kareem A, Reynolds, Christopher S, and Armitage, Philip J. CONNECTIONS BETWEEN LOCAL AND GLOBAL TURBULENCE IN ACCRETION DISKS. United States: N. p., 2010. Web. doi:10.1088/0004-637X/712/2/1241.
Sorathia, Kareem A, Reynolds, Christopher S, & Armitage, Philip J. CONNECTIONS BETWEEN LOCAL AND GLOBAL TURBULENCE IN ACCRETION DISKS. United States. https://doi.org/10.1088/0004-637X/712/2/1241
Sorathia, Kareem A, Reynolds, Christopher S, and Armitage, Philip J. 2010. "CONNECTIONS BETWEEN LOCAL AND GLOBAL TURBULENCE IN ACCRETION DISKS". United States. https://doi.org/10.1088/0004-637X/712/2/1241.
@article{osti_21394204,
title = {CONNECTIONS BETWEEN LOCAL AND GLOBAL TURBULENCE IN ACCRETION DISKS},
author = {Sorathia, Kareem A and Reynolds, Christopher S and Armitage, Philip J},
abstractNote = {We analyze a suite of global magnetohydrodynamic (MHD) accretion disk simulations in order to determine whether scaling laws for turbulence driven by the magnetorotational instability, discovered via local shearing-box studies, are globally robust. The simulations model geometrically thin disks with zero net magnetic flux and no explicit resistivity or viscosity. We show that the local Maxwell stress is correlated with the self-generated local vertical magnetic field in a manner that is similar to that found in local simulations. Moreover, local patches of vertical field are strong enough to stimulate and control the strength of angular momentum transport across much of the disk. We demonstrate the importance of magnetic linkages (through the low-density corona) between different regions of the disk in determining the local field, and suggest a new convergence requirement for global simulations-the vertical extent of the corona must be fully captured and resolved. Finally, we examine the temporal convergence of the average stress and show that an initial long-term secular drift in the local flux-stress relation dies away on a timescale that is consistent with turbulent mixing of the initial magnetic field.},
doi = {10.1088/0004-637X/712/2/1241},
url = {https://www.osti.gov/biblio/21394204}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 712,
place = {United States},
year = {Thu Apr 01 00:00:00 EDT 2010},
month = {Thu Apr 01 00:00:00 EDT 2010}
}