Toroidal field ripple loss of neutral-beam-injected fast ions is measured from the heat load on the first wall in JT-60U. The heat load is localized in both toroidal and poloidal directions and increases with both ripple size and safety factor. The overall measured ripple loss is in good agreement with an orbit-following Monte Carlo calculation. Nevertheless, there is a small difference between the experimental and the calculated location of the maximum heat load, which suggests that the radial electric field shifts the impinging points of ripple-trapped ions on the first wall.
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