1 - Nuclear Sciences and Applications - IAEA

162 JET TEAM
3. H-mode Characteristics
3.1 Time evolution of H-mode discharges
The characteristic time evolution of various plasma parameters for JET H-mode
discharges is shown in Fig. 3 for a 3 MA discharge (# 15894). Characteristic of
most JET H-modes is the absence or very low level of ELM activity throughout
the whole H-mode phase. This results in a continuous rise in plasma density
and a concomitant increase in bulk plasma radiation which finally terminates
the H-mode (longest H-phase — 4 s) when the bulk radiation reaches about 60%
of the input power. The increase in the total energy content of the plasma, W,
during the H-phase results largely from the plasma density increase, while the
central electron temperature, Teo, is roughly constant or even decreasing slightly
with time.
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