HR: 1340h
AN: SM43A-1210    [Abstracts]
TI: MHD Shallow-Water Turbulence on the Sphere
AU: * Staehling, E M
EM: estaehli@bucknell.edu
AF: Department of Physics, Bucknell University, 701 Moore Ave, Lewisburg, PA 17837 United States
AU: Cho, J Y
EM: jcho@dtm.ciw.edu
AF: Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015 United States
AB: Motivated by astrophysical-geophysical applications, we have performed a series of high Reynolds number simulations of freely-evolving, magnetohydrodynamic shallow-water turbulence (MHDSWT) on a rotating sphere. MHDSWT is the simplest turbulence model that allows the effects of stratification, differential rotation, and magnetic field to be studied over long durations. A systematic exploration of the full physical and numerical parameter-space shows novel as well as consistent behavior, compared to pure hydrodynamic (HD) and 2-D MHD counterparts. In the case without rotation, our simulations show that the turbulent evolution is sensitive to initial conditions, with the strongest dependence on the peak of the initial energy spectrum. With increasing magnetic field strength, the flow field is more susceptible to loss of balance, and the field blows up in finite time. In addition, the pronounced anisotropic structures (jets and vorticity bands) observed in differentially-rotating HD systems do not form. An application of the model to the solar tachocline is also presented.
DE: 2753 Numerical modeling
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005