Psep/PLH control in deuterium and deuterium–tritium JET plasmas

The high confinement mode (H-mode) is a promising route to achieve high performance tokamak operations, as the ones foreseen in ITER and beyond. However, accessing a stable H-mode phase requires that the power across the plasma separatrix, P_sep, exceeds a certain power threshold, P_LH. Feedback control can be utilized in this context to guide the H-mode entry and exit, and to tailor its evolution throughout the pulse by monitoring f^Net_LH defined as the ratio of P_sep over P_LH. Such a controller has been integrated into the JET plasma control system, using the neutral beam power and the gas puffing as actuators. In this work, we document successful P_sep/P_LH control studies carried out in deuterium and deuterium-tritium plasmas, which pave the way for using this portable controller in ITER and next step fusion devices.