A more in depth investigation of the equilibrium and stability analysis of the bean and oval sawtooth experiments revealed some additional surprises. The growth rate does not fully follow the sawtooth cycle and is quite different in the two cases but new analysis shows that the local shear at q=1 tracks the ideal growth rates in both cases. None of the other key variables q₀, q_min, r(q0) and r(q_min), is strongly correlated. Also, there is a small event about a third of the way into the sawtooth ramp in both cases, which causes a small drop in Te. The analysis revealed that for the bean case, the ideal unstable mode is a quasi-interchange until this event, after which the plasma becomes ideally stable for a sizeable fraction of the sawtooth period until, as reported earlier (see http://fusion.gat.com/theory/Weekly0407 and http://fusion.gat.com/theory/Weekly0908), the internal kink becomes unstable somewhat before the final sawtooth crash. For the oval, the growth rate drops after the event but the plasma is not fully stabilized and the mode remains a quasi-interchange throughout. The implications for interpreting the experimental observations are being worked through.

An initial version of a visualization program written using C++ with OpenGL allows for real-time interactive 3D viewing of magnetic field lines produced from the TRIP3D code. Visualization from arbitrary viewing angles and camera positions, as well as a poloidal slice from an arbitrary toroidal angle, allow detailed inspection of potentially complicated perturbed field line geometry. Color gradients along field lines allow the user to rapidly visualize instances where many toroidal rotations of the same line are displayed. Magnetic perturbation coil locations with coil current information represented by color are also displayed.

The first test of the Trapped Gyro-Landua Fluid (TGLF) transport model with data from MAST has been completed in collaboration with Greg Colyer from Culham Laboratory. It was found that outside the sawtooth region (q > 1) TGLF predicted the ion and electron temperatures to within 17% and 26% respectively for eight discharges. The electron temperature prediction was on average 11% too high whereas the ion temperature was 4% too low. It was found that electron-ion collisions play an important role in improving the transport by reducing the trapped electron drive. The new electron-ion collision model in TGLF, which improves the fidelity to gyro-kinetic theory, also resulted in an improved prediction of the MAST temperatures. In addition, the shaped geometry modification to the Chang-Hinton formula proposed by Belli and Candy to give better agreement with the NEO code numerical neoclassical ion thermal diffusivity has a significant impact on the ion temperature prediction. The Belli-Candy modification yields much better agreement with the data. This motivates coupling the NEO code to the transport code in the future.