Towards Real Time Control of the Internal Transport Barriers on JET

Recently a local criterion characterising the emergence and space-time evolution of Internal Transport Barriers (ITB) has been proposed and extensively validated on the large JET database [1]. It was shown that a dimensionless local parameter, r*Te = rS / LTe characterises with a low computational cost the typical ITB features such as the emergence time, location, collapse time and dynamics [rS is the local Larmor radius and LTe is the temperature gradient scale length LTe = - Te (ðTe /ðR) ]. We report on the recent implementation of the calculation of the ITB criterion together with the associated feedback algorithms in the real time system of JET. The system purpose is to acquire all the analogue channels of the high space resolution electron temperature ECE diagnostic (heterodyne radiometer) and to calculate in real time the relevant ITB parameters which are used for the control: the maximum value of the dimensionless local temperature gradient, the ITB radius and width, the core and volume averaged electron temperature.
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EFDC020406 1.10 Mb