Pressure Driven Transport In The Core Of Tokamak Plasmas

There is experimental and theoretical evidence of anomalous transport near the magnetic axis in tokamak plasmas, a region in which drift modes are linearly stable. Experimental evidence suggests that this additional transport is strongly affected by the plasma geometry (i.e., elongation and triangularity), more so than drift modes[1]. The finite-beta kinetic ballooning instability is predicted to exist close to the magnetic axis and is strongly affected by the plasma geometry. In this study, we explore the properties of the kinetic ballooning mode with the comprehensive electromagnetic kinetic stability calculations of the FULL code. Using FULL, we quantify the parametric dependence of kinetic ballooning transport on various plasma parameters, including the flux-surface elongation and triangularity, the normalized pressure beta and the flux-surface inverse aspect ratio. Based on these stability calculations, an algebraic kinetic ballooning transport model is developed. Also included in this dissertation are two independent studies of transport in tokamak plasmas, carried out with the BALDUR predictive transport code. In the first study, the sensitivity of these transport simulations to boundary and initial conditions is examined. In the second, a transport model developed by Ottaviani, Horton and Erba (OHE) is incorporated into the BALDUR code, and the density and temperature profiles predicted by this model are compared to experiment for a series of experimental discharges.