Residual stress and pinch contributions to momentum transport in JET neutral beam heated H-modes

NA broad survey of the experimental database of neutral beam heated baseline and hybrid scenarios in the JET tokamak with the C-wall was undertaken and has established the ubiquity of non-diffusive momentum transport mechanisms in externally driven, strongly rotating plasmas. The experimentally identified non-diffusive contributions to the gradient are largely consistent with the theoretically expected Coriolis pinch. The predicted non-diffusive transport using the GKW code is about 30% lower on average, than inferred from observation, suggesting that the difference may be due to residual stresses. In this case a scaling with Ors=rho_i*(R/L_Ti)2/u would be expected. However a lack of scaling of the angular velocity gradients with Ors=rho_i*(R/L_Ti)2/u throughout the plasma minor radius leads to the conclusion that there is no evidence for significant residual stress contributions in these fast rotating plasmas.

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