The Hybrid Scenario in JET: Towards its Validation for ITER

In 2003, the performance of the hybrid regime have been successfully validated in JET up to bN = 2.8 at low toroidal field (1.7T), with plasma triangularity and normalised Larmor radius (r*) corresponding to identical ASDEX Upgrade discharges. Stationary conditions have been achieved with the figure of merit for fusion gain (H89.bN/q952 ) reaching 0.42 at q95 = 3.9. The JET discharges are showing similar MHD, edge and current profile behaviour than in ASDEX Upgrade. In addition, the JET experiments have extended the hybrid scenario operation at higher toroidal field 2.4T and lower r* towards projected ITER values. Using this database, transport and confinement properties are characterised with respect to the standard H-mode regime. Moreover, trace tritium have been injected to assess the diffusion and convective coefficients of the fusion fuel. The maximisation of confinement and stability properties provides to this scenario a good probability for achieving high fusion gain at reduced plasma current for duration up to 2000s in ITER.
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