Burning Plasma Physics Issues in a Possible Jet Upgrade

Record fusion yield (16MW) and fusion energy (22MJ) have been achieved in JET during the DTE1 campaign in 1997 [1], [2], respectively with an ELM-free H-mode and with an ELMy Hmode. Alpha heating has been observed [3] with alpha power in the range of 1.2MW. Significant fusion yield (up to 8MW) has been achieved with advanced scenarios [4]. These results have generated a large number of significant advances in the physics of fusion plasmas. It is felt that more significant burning plasma physics issues could be addressed in a JET upgrade. Increasing power capability would allow to access high confinement modes and to assess beta limits at full field. Increasing plasma volume would allow to increase plasma current and the fusion gain. Increasing plasma shaping would allow to operate at higher densities and to increase the ELM-free period of ELM-free H-modes. Increasing both plasma volume, plasma shaping and power capability would allow: i) to increase significantly JET performances, ii) to reduce errors in Next step extrapolation, iii) to operate at much higher values of fusion yield and alpha heating power and to tackle some burning plasma physics issues, which are needed to progress towards a fusion reactor.