Astronomy and Astrophysics – Astrophysics – High Energy Astrophysical Phenomena
Scientific paper
2009-03-22
Astrophys.J.697:1901-1906,2009
Astronomy and Astrophysics
Astrophysics
High Energy Astrophysical Phenomena
15pages, 1 figure, accepted by ApJ
Scientific paper
10.1088/0004-637X/697/2/1901
The magnetic Prandtl number Pr_M is the ratio of viscosity to resistivity. In astrophysical disks the diffusion of angular momentum (viscosity) and magnetic fields (resistivity) are controlled by turbulence. Phenomenological models of the evolution of large scale poloidal magnetic fields in disks suggest that the turbulent magnetic Prandtl number Pr_{M,T} controls the rate of escape of vertical field from the disk; for Pr_{M,T} leq R/H vertical field diffuses outward before it can be advected inward by accretion. Here we measure field diffusion and angular momentum transport due to MHD turbulence in a shearing box, and thus Pr_{M,T}, by studying the evolution of a sinusoidal perturbation in the magnetic field that is injected into a turbulent background. We show that the perturbation is always stable, decays approximately exponentially, has decay rate proportional to k^2, and that the implied Pr_{M,T} ~ 1.
Gammie Charles F.
Guan Xiaoyue
No associations
LandOfFree
The Turbulent Magnetic Prandtl Number of MHD Turbulence in Disks does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Turbulent Magnetic Prandtl Number of MHD Turbulence in Disks, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Turbulent Magnetic Prandtl Number of MHD Turbulence in Disks will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-345729