Analysis of Momentum Transport in Alcator C-Mod Plasmas with No Momentum Input using a Simplified Diffusion Model

High resolution x-ray spectrometers have shown propagation of momentum from the edge to the center of Alcator C-Mod plasmas. This propagation was modeled by a one dimensional, source free momentum transport equation (ignoring convection and treating boundary conditions as a step function). Using this model to fit the central velocities of the EDA H-modes and L-modes yields a diffusivity coefficient, which corresponds to a momentum confinement time, $\tau _{\phi }$. Comparing $\tau _{\phi }$ with plasma parameters provides means to determine which, if any, correlations exist for the momentum confinement time.