1 - Nuclear Sciences and Applications - IAEA

IAEA-CN-SO/AIV-4 253
FIG. 4. (a) Diamagnetic energy content against heating power and (b) plasma energy content against
heating power for a set of 3 MA/2.8-3.4 T discharges. A: Te > 9 keV, D: 7] > 9 keV, o : Te and
T, > 9keV, Q>:ne > 3.5 x 10 19 m' 3 and Te < 6 keV, it: pulse 16066 (Fig. I) and S: pulse 16981
(Fig. 5).
considerable spread, with the high density plasmas having the
lowest energy contents.
The plasma energy content, determined from magnetic
measurements assuming that all fast ions are perpendicular, is
plotted against heating power in Fig. 4(b). The spread is now
rather small and the different groups are interspersed with no
apparent trend in either temperatures or density. The spread in
the diamagnetic energy must be predominantly due to fast ions.
The plasma energy confinement is apparently insensitive to
overall temperature (or density) variations of a factor of two.
The heating rates for the electrons and ions are very similar
(Te/i(O) * 2-3xl0 18 Po/1(MW)/ne(0) keV). 1-D transport
simulations [7] of these plasmas require that the ion and
electron thermal conductivities be approximately equal in order
to satisfactorily reproduce the data. However, at the time of
writing, the local transport analysis of the hot electron and
hot ion plasmas has not been completed.
By pushing the plasma to a smaller minor radius on the
inside wall, plasmas which are similar to the TFTR "supershots"
[4] have been produced. Figure 5 shows the temperature and
density profiles in one of these pulses (JET pulse 16981). The
characteristic narrow electron density and broad temperature
profiles can be seen. This pulse has been identified in Fig. 4.