Astronomy and Astrophysics – Astrophysics
Scientific paper
2000-12-20
Astronomy and Astrophysics
Astrophysics
41 pages, 12 figures, to be published in ApJ (vol. 556)
Scientific paper
10.1086/321607
We apply a Fourier spectral numerical method to 3D incompressible MHD turbulence with a magnetic Prandtl number $Pr \geq 1$. We examine the processes by which an initially weak, large-scale seed magnetic field and an initially weak, small-scale, impulse-like seed magnetic field are amplified. We find that in both cases the magnetic energy spectrum grows at all scales. The growth rates at different amplification stages are analyzed. For a large-scale seed magnetic field, the magnetic energy density grows as $\sim t^2$ for the first few turbulence eddy turnover times, followed by a dynamic growth stage, where nonlinear interactions between different scales of the turbulence contribute to an exponential growth rate that is largely determined by the turbulence eddy turnover time. For a seed magnetic field that is initially set up at a small scale in the turbulence, during the kinematic development stage, the growth rate of magnetic energy is $\propto 1/\tau_{max}$, where $\tau_{max}$ is the eddy turnover time of the smallest eddies of the turbulence. The kinematic growth stage is followed by a dynamic growth stage, where nonlinearity plays important role. During such dynamic growth stage, the growth rate of total magnetic energy is determined by both the magnetic energy amplification within the turbulence inertial range and that within the turbulence dissipation range.
No associations
LandOfFree
Numerical Analysis of Magnetic Field Amplification by Turbulence 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 Numerical Analysis of Magnetic Field Amplification by Turbulence, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Numerical Analysis of Magnetic Field Amplification by Turbulence will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-662421