1 - Nuclear Sciences and Applications - IAEA

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IAEA-CN-50/A-V-4 311
1 1
na=3.1x10 l9 nri 3 , iP= 1.4 MA
ne=3.1xi0 19 m' 3 . lp= 0.8 MA
ne-1.6x10 l9 m 3
Re= 1.6x1o'V 3
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0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
MINOH RADIUS (m)
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1.4 MA
0.8 MA
FIG. 2. Inward pinch velocity as a function of radius for the four plasma conditions in Fig. 1.
convective flux terms ascertained in the analysis. The analysis has been
redone with no source term and the transport coefficients changed by only
10-15% for the low density case at r > 0.5 m. The error bars associated with
the transport coefficients in the two figures are on the order of +/- 50% at all
radial positions, and reflect the uncertainty in determining the density gradient
at any position.
Good regression fits at all radii to the flux model were not always
possible, especially at radii r < 0.15 m, where the integrated flux is low and
sawtooth mixing occurs. The best of those poor fits indicates that the
transport coefficients are lower than or equal to those at r = 0.2 m. Systematic
studies are now underway to investigate the sensitivity of the transport
coefficients to the size of the gas puff. For variations in the density
perturbations on the order of An / n < 10%, there is no noticeable variation in
the transport coefficients. However, in a recent case where the density
increase was 100%, the simple flux model does not give good fits. The
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