1 - Nuclear Sciences and Applications - IAEA

304 ZURRO et al.
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50 100
f(kHz)
SO 100
f (kHz)
FIG. 4. (a) Coherence and (b) phase angle between density and potential fluctuations; (c) spectrally
resolved flux.
confinement time measured by the laser ablation technique can be considered
representative of the central particle confinement time in TJ-I. Its empirical variation
with toroidal field, which shows a unique behaviour in TJ-I plasmas, correlates
reasonably well with the global confinement time deduced from the particle flux
driven by electrostatic fluctuations at the edge.
The main uncertainties in this comparison stem from the following points:
First, the global particle confinement time, with which the fluctuation deduced confinement
time should be compared, could be a factor one to three smaller than the
central value [6, 7] since the particles are better confined at the centre than at the
edge. Second, the measurements of fluctuation induced transport were made only at
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