Abstract
Fast-ion transport caused by the combination of MHD and a mock-up test-blanket module (TBM) coil is measured in the DIII-D tokamak. The primary diagnostic is an infrared camera that measures the heat flux on the tiles surrounding the coil. The combined effects of the TBM and four other potential sources of transport are studied: neoclassical tearing modes, Alfén eigenmodes, sawteeth, and applied resonant magnetic perturbation fields for the control of edge localized modes. A definitive synergistic effect is observed at sawtooth crashes where, in the presence of the TBM, the localized heat flux at a burst increases from to MW m−2.
Highlights
The proposed ITER tritium-breeding test blanket modules (TBMs) [1] are expected to contain ferromagnetic materials that will perturb the nearby plasma with ∼1% local magnetic field reductions
The concern remains that instabilities may transport alpha particles from the populated core region to the plasma edge, where the TBM fields are effective [2, 3]
Since a major goal of the present study is to provide data for code benchmarking within the framework of the International Tokamak Physics Activity (ITPA) Topical Group on Energetic Particles, each section contains information on the MHD modes, core fast-ion transport, and localized heating
Summary
The proposed ITER tritium-breeding test blanket modules (TBMs) [1] are expected to contain ferromagnetic materials that will perturb the nearby plasma with ∼1% local magnetic field reductions These field perturbations could cause concentrated losses of alpha particles that damage the wall near the TBMs. Calculations [2] indicate that, in the absence of additional fast-ion transport mechanisms, the alpha loss power fraction will be very low, ∼0.2%. The strategy in the present experiment is straightforward: with the TBM either on or off, compare the localized heat flux in plasmas with identical MHD In some cases, these comparisons are performed in sequential discharges while, in others, comparisons are possible at different times in the same discharge (figure 2).
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call