Experiments at DIII-D investigated the effects of ferromagnetic error fields similar to those expected from proposed ITER Test Blanket Modules (TBMs). Studied were effects on: plasma rotation and locking; confinement; L-H transition; edge localized mode (ELM) suppression by resonant magnetic perturbations; ELMs and the H-mode pedestal; energetic particle losses; and more. The experiments used a 3-coil mock-up of 2 magnetized ITER TBMs in one ITER equatorial port. The experiments did not reveal any effect likely to preclude ITER operations with a TBM-like error field. The largest effect was slowed plasma toroidal rotation ν across the entire radial profile by as much as Δν/ν0 ~50% via non-resonant braking. Changes to global Δn/n, Δβ/β and ΔH98/H98 were ~3 times smaller. These effects are stronger at higher β and lower ν. Other effects were smaller. The TBM field increased sensitivity to locking by an applied n=1 test field, but it was nulled in an L-mode plasma by re-adjusting the DIII-D n=1 error field compensation system. Numerical modeling by IPEC reproduces the locking semi-quantitatively and predicts similar compensation of locking in H-mode.
|23rd IAEA Fusion Energy Conference, FEC 2010
|Korea, Republic of
|10/10/10 → 16/10/10