Parameter estimation in a tokamak transport model and application to L- and H-mode simulations

A systematic parameter estimation method has been established and applied to estimating a priori uncertain multipliers of flux formulas in a gyro-Bohm tokamak transport model. Results from simulating two tokamak discharge profiles with the model calibrated here are shown. The method used here can deal with limited and relatively uncertain experimental data by using estimates of prior knowledge concerning the accuracy of the data. Confidence regions are given to assess the accuracy of estimators. The estimated multipliers are much larger than in a similar study using a nongyro-Bohm transport model suggesting that mechanisms, in addition to early estimates of E×B driven fluxes from resistive ballooning and quasi-linear drift/η_i turbulence, are needed for a complete theoretical model of flux surface-averaged transport in tokamaks