Theory Weekly Highlights for December 1999

December 17, 1999

The model in which plasma rotation can be sustained in a tokamak by ICRF, even though the heating process itself deposits no net angular momentum, has been shown to reproduce the magnitude, sense of rotation, and rotation profile observed on C-Mod. The mechanism was also shown to be insensitive to particle energy, initial particle pitch (ie banana vs. circulating orbits), and q-profile. However, the sense of rotation is sensitive to whether the ICRF resonance location lies on the high-field-side or low-field-side of the magnetic axis. So far, C-Mod data are only for low-field-side resonance locations which yield co-current rotation. When C-Mod resumes operations in April, tests of whether high-field-side resonances yield counter-current rotation will be possible.

December 03, 1999

The NCLASS neoclassical transport model has been implemented in the ONETWO transport code and is available for use. NCLASS calculates the transport fluxes, neoclassical resistivity, viscosities, and bootstrap current for a multi-species plasma of arbitrary aspect ratio, geometry and collisionality. Online HTML documentation describing both the physics and use of the model is available through the web site at

The TORAY ECH ray tracing code has been parallelized with MPI and tested on the LUNA PC Linux cluster. With 30 rays, the CPU time was approximately 34 secs using 1 processor and was approximately 2.6 secs using 15 processors. This complements the other two physics modules associated with the Onetwo code that have been parallelized with MPI, GLF23 and FREYA. Future plans are to port the entire Onetwo code to a Linux Beowulf system and demonstrate efficient use of all three physics modules.

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