Recent experiments performed by a team of international scientists on the
Error field correction of both the intrinsic magnetic field errors in DIII-D and the magnetic field errors produced by the TBM mockup (red) show that plasma performance (denoted by bN) drops by only 3.5% when error field corrections are optimized. The plasma rotation is an even more sensitive measure of the effect of error fields and the total angular momentum of the plasma (Ltot) is reduced by 15% with optimized error field correction.
With the optimum correction fields, it was possible to run the DIII-D plasmas at high performance with almost no degradation in performance due to the TBM mockup. In the graph above, the normalized energy confinement of the plasma (denoted by βN) hardly decreases with optimized error field corrections, though a more sensitive measure of the effects of error fields—the total angular momentum of the plasma—drops by about 15 percent when a single row of external coils is used. Similar results were found using internal correction coils.
The team of international scientists that worked on the TBM mockup experiments on the DIII-D tokamak in San Diego included Joseph Snipes (5th from right), Stability & Control Section leader from the ITER Organization.