We have carried out time-dependent transport analysis calculations using experimentally determined plasma parameters to obtain the variation of electron and ion thermal diffusivities following pellet injection into moderate density ALCATOR C discharges. The ion thermal diffusivity, which is typically higher than neoclassical predictions by a factor of four in the gas fueled target plasma, is found to decrease following injection to approximately the neoclassical value. The electron thermal conductivity is not reduced following injection. The improvement in ion transport correlates with the peaking of the density profile and may be related to the reduction in the quantity dln Ti/dln n in the pellet fueled case. Extrapolation of these results to higher density plasmas, for which the electron and ion losses cannot be unambiguously measured, is consistent with previously reported increases in global energy confinement time accompanying pellet injection.
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