High Resolution Density Profile Measurement for Electron Transport Studies in DIII-D

High temporal (to 10 $\mu$s) and spatial ($\sim$0.5 cm) resolution measurements of density profile evolution via profile reflectometry have been performed in a variety of plasma conditions in DIII-D. These measurements are currently applied to study particle transport. As one example, in a D$_2$ gas puffing modulation experiment, it is observed that the $n_e$ modulation can propagate from the edge inward to $\rho\sim 0.4$. The dependence of the modulations on $q$ and collisionality is under investigation. In an experiment with EC power alternately deposited at two close positions, it has been seen that the $n_e$ profile is significantly modulated by the EC modulations when the EC power at two locations is unbalanced. The $n_e$ modifications become smaller when the EC power is balanced. For these $n_e$ modulation datasets, an FFT transport analysis technique will be applied to investigate transport coefficients and particle pinch velocity. In addition, the associated $n_e$ fluctuations over a broad range of $k$ will be presented.