[GTP] GTP Seminar at NCAR--Ed Lee--NEW DATE and LOCATION

[Silvia Gentile]

Comparison of three classes of symmetric MHD decay flow simulations with 
high resolution DNS

Three different MHD decay flows displaying Taylor-Green-type symmetries 
are computed at high resolution using an efficient, parallel, spectral 
code customized to exploit the flow symmetries without loss of accuracy. 
Different phenomenological behavior is identified for the three classes 
of flows, where the occurrence of Alfven waves, micro-instabilities, and 
dynamic alignment are found to be dependent on initial conditions and 
Reynolds numbers, which determine characteristic time scales, such as 
the Alfven and eddy turnover times.  All of the flows are 
three-dimensional and deliberately quasi-isotropic to better understand 
small-scale behavior in the absence of a mean magnetic field.  Strong 
background magnetic fields, common in geophysical and astrophysical 
plasma environments, are known to suppress energy transfer in the 
parallel direction and therefore may limit the dynamical possibilities 
of MHD.  In this study, both isotropic and anisotropic tools are used to 
assess and interpret the physics of the flows, which are postulated to 
be unchanged by the symmetries implemented in the code.


Ed Lee
Turbulence Numerics Team, IMAGe (NCAR)
January 20 at  2pm
Center Green Laboratory 1--Rm 2126