1 - Nuclear Sciences and Applications - IAEA

642 ALLADIO et al.
3
ID
10 2
10'
10°
10 1
". 0.5
tu
• a a o a
•V.
3 FAST
•SLOW
2 4 6 8 10 12 14 16
ne/10"(cm- 3 )
FIG. 4. (a) Intensity ofECE at a> = 1.6 oice, normalized to RF power as a function of density for two
different spectra; (b) Ratio ofECE intensities at a — 1.4 uce and a> = 1.6 uce as a function of density.
Radiation is only emitted in this range by fast electrons through the down shifted
second harmonic emission. On the assumption that the perpendicular velocity is much
lower than the parallel one, a precise n0 value corresponds to each detected frequency.
In particular, nB = 1.4 corresponds to co = 1.4 wce and ny = 1.67 to
w = 1.6 oice.
ECE measurements are available for BT = 8 T and n,. < 1.4 X 10 14 cm" 3 .
In this density range, the power component with nj = 1.67 can reach the plasma
centre while the component with n] = 1.4 is converted to fast wave before reaching
the plasma core.
In Fig. 4(a), we show the ECE intensity at w = 1.6 wce normalized to RF
power both for fast and slow spectra. As is expected, the fast spectrum yields a