Astronomy and Astrophysics – Astrophysics
Scientific paper
2000-12-23
Astronomy and Astrophysics
Astrophysics
56 pages, 30 figures, submitted to ApJ 59 pages, 31 figures, accepted to ApJ
Scientific paper
10.1086/321413
We simulate incompressible MHD turbulence in the presence of a strong background magnetic field. Our major conclusions are: 1) MHD turbulence is most conveniently described in terms of counter propagating shear Alfven and slow waves. Shear Alfven waves control the cascade dynamics. Slow waves play a passive role and adopt the spectrum set by the shear Alfven waves, as does a passive scalar. 2) MHD turbulence is anisotropic with energy cascading more rapidly along k_perp than along k_parallel, where k_perp and k_parallel refer to wavevector components perpendicular and parallel to the local magnetic field. Anisotropy increases with increasing k_perp. 3) MHD turbulence is generically strong in the sense that the waves which comprise it suffer order unity distortions on timescales comparable to their periods. Nevertheless, turbulent fluctuations are small deep inside the inertial range compared to the background field. 4) Decaying MHD turbulence is unstable to an increase of the imbalance between the flux of waves propagating in opposite directions along the magnetic field. 5) Items 1-4 lend support to the model of strong MHD turbulence by Goldreich & Sridhar (GS). Results from our simulations are also consistent with the GS prediction gamma=2/3. The sole notable discrepancy is that 1D power law spectra, E(k_perp) ~ k_perp^{-alpha}, determined from our simulations exhibit alpha ~ 3/2, whereas the GS model predicts alpha = 5/3.
Goldreich Peter
Maron Jason
No associations
LandOfFree
Simulations of Incompressible MHD 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 Simulations of Incompressible MHD Turbulence, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Simulations of Incompressible MHD Turbulence will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-321084