3 papers
astro-ph2004
Helical coronal ejections and their role in the solar cycle
Axel Brandenburg, Christer Sandin, Petri J. Käpylä
The standard theory of the solar cycle in terms of an alpha-Omega dynamo hinges on a proper understanding of the nonlinear alpha effect. Boundary conditions play a surprisingly imp…
physics.flu-dyn2004
Passive scalar diffusion as a damped wave
Axel Brandenburg, Petri Käpylä, Amjed Mohammed
Three-dimensional turbulence simulations are used to show that the turbulent root mean square velocity is an upper bound of the speed of turbulent diffusion. There is a close analo…
astro-ph2001
Numerical study of the magnetorotational instability in weakly magnetised accretion disks: Resolution dependence of the Shakura-Sunyaev alpha
P. J. Kapyla, M. J. Korpi
In this letter, we present numerical calculations made to investigate the possible resolution dependence of the Shakura & Sunyaev (1973) viscosity parameter alpha from local magnet…