EXPERIMENTAL-DETERMINATION OF NONDIFFUSIVE TOROIDAL MOMENTUM FLUX IN JT-60U

Toroidal momentum transport is examined experimentally by using on- and off-axis tangential neutral beam injections on the JT-60U tokamak. From a steady state momentum balance analysis - on the assumption that momentum flux is diffusive - it is found that the profiles of the momentum diffusivity are quite different in the two cases of on- and off-axis beam injections. In addition, transient toroidal momentum transport was examined by using a momentum source modulation experiment. On the assumption that the toroidal momentum flux consists of a diffusive and a convective flow term, it is found that there is non-diffusive inward flux of toroidal momentum whose absolute value is comparable to that of the diffusive flux.