Multi-Machine Transport Analysis of Hybrid Discharges from the ITPA Profile Database
Current diffusion, heat transport modelling, and linear gyrokinetic stability analysis have been carried out on a set of 7 hybrid discharges from AUG, DIII-D, JET and JT-60U, in order to gain better understanding of the physics underlying this promising candidate scenario for ITER. Within this dataset, the GLF23 model has a higher accuracy than the Weiland model in predicting the temperature profiles in the region 0.3 < r < 0.8. The core heat transport appears to be similar between hybrid discharges and standard H-modes, and also among hybrid discharges with very different H factors. Projections to ITER show that Q = 10 can be obtained with the hybrid scenario using an alternative scaling without b degradation. However, additional off-axis current drive and current profile control might be needed for the ITER hybrid scenario, in order to achieve its full potential for high bN on extended duration.