Numerical Scaling with the COREDIV Code of JET Discharges with the ITER‐Like Wall

After the code parameters have been fixed by the numerical modeling of a well diagnosed JET pulse, the electron density and the input power have been changed, resulting in 4 density scans ( 〈n e 〉 in the range 3.8 – 8.2 x 10 19 m ‐3 ) at P in = 17, 22, 27, 32 MW. At any given power level, W flux decreases with increasing 〈n e 〉 as a consequence of the decrease in T e at the target plates. Also the W concentration in the core ( cW ) decreases, but this not necessarily leads to reduced core radiation. Indeed, while at high P in the core radiation decreases with density, at low P in it increases. At high 〈n e 〉 the increase in the input power leads to enhanced P rad Prad , leaving, however, nearly unchanged the power radiated fraction f rad Indeed, the increase in f rad with P in is observed only at low 〈n e 〉 , up to a level of about f rad = 0.4. These numerical results, linked to the non‐linear self‐consistent physics of W production and transport, suggest the best conditions are achieved when the level of the electron density is adapted to the level of the available P in . (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)