Theory Weekly Highlights for November 2006

November 22, 2006

Jeff Candy gave two oral presentations at the Supercomputing 2006 Meeting in Tampa, FL. At the invitation of CRAY, he presented “Fusion plasma simulations on the Cray X1E using the GYRO code” at the CRAY booth. At the invitation of NCCS (ORNL), he also presented “Multiscale Coupling in Tokamak Turbulence”.

November 17, 2006

After the release of the new collaborative Wiki-based fusion web site, many pages have been converted into Wiki pages. These web sites take advantage of Mediawiki so that web pages can be collaboratively created and maintained by all users. The majority of the DIII-D and Theory web sites have now been converted. Recently transferred sites include Theory (, GYRO (, Thrust IT-2 ( and the Beam Emission Spectroscopy: ( The remainder of the sites will follow as requested and as time allows.

November 10, 2006

A set of coupled ITG/TEM-ETG gyrokinetic simulations using GYRO, made possible by a DoE INCITE06 large computer time award, found that high-k turbulence was remarkably isotropic, making interpretation of the DIII-D high-k diagnostic data much easier. These expensive simulations were the first ETG simulation with kinetic ions and ExB shear. The simulations also found that when both low-k ITG/TEM and high-k ETG are strongly unstable, the nonlinear coupling was found to be rather weak; high-k and low-k transport can be more cheaply simulated independently. However, an accurate turbulence spectrum still requires expensive simulations. ETG transport survives ExB shear stabilization of the low-k transport. Most surprisingly, it was found that high-k ETG transport could be driven by the low-k instabilities even when the ETG modes are stable. R.E. Waltz highlighted these results in an invited APS06 talk entitled “Coupled ITG/TEM-ETG Gyrokinetic Simulations”.

November 03, 2006

Three GA theory invited papers were presented at the 48th American Physical Society Meeting held in Philadelphia, PA, from Oct 30 through November 3, 2006. These were: “Resistive Stability of 2/1 Modes near 1/1 Resonance” by D.P. Brennan (now at University of Tulsa), “A Theory-Based Transport Model with Comprehensive Physics” by G.M. Staebler, and “Coupled ITG/TEM-ETG Gyro-Kinetic Simulations” by R.E. Waltz.

These highlights are reports of research work in progress and are accordingly subject to change or modification