1 - Nuclear Sciences and Applications - IAEA

IAEA-CN-50/A-I-1
However, reasonable agreement, particularly with the Michelson relative electron
temperature profile (Fig. 9), has been obtained for the following set of plasma
characteristics: Ip = 590 kA, POhm = 450 kW, Zeff = 2.5, ne = 1.9 X 10 19 m" 3 ,
q(0) = 0.8, TE = 0.125 s, Te(0) =1.6 keV. The impurity transport code [6], using
plasma parameters and the evaluated light impurity content, shows the radiation
losses to lie between 50 and 60 kW (depending on the assumed value of the transport
coefficients).
3.2. Runaway electrons (RE)
Figure 10 shows the time evolution of the photoneutron signal due to runaway
electrons lost in the limiter. The first neutrons are detected 50 ms after plasma breakdown,
their flux then increasing during ~0.5 s, with a few short spikes related to
the crossing of integer q surfaces at the plasma edge. Afterwards, the signal decreases
with a time constant of 1 to 2 s. The total neutron emission per shot ranges between
10 9 and 10", corresponding to a maximum RE current of -0.05% of the total
current.
5 -
0 -
FIG. 11. Time evolution of photoneutron flux and plasma current in terms of energy limit of confined
runaways, at the end of a short discharge.
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