Data analysis on TFTR using the SNAP transport code

Abstract

This paper describes the between shots data analysis on TFTR using the one-dimensional equilibrium kinetic analysis code SNAP. SNAP accepts as input data: the measured plasma size and current, toroidal field, surface voltage, plasma composition (total Zeff and Zeff contribution from metallic impurities), edge neutral density, auxiliary heating power data (neutral beam power, energy, injection geometry and/or rf power and frequency), and measured profiles of Te(R), ne(R), Ti(R), Vφ(R), and Prad(R). SNAP iteratively calculates: (1) the mapping of profile data to a minor radius grid, (2) the magnetic topology including Shafranov shifted circular flux surfaces, (3) neutral beam attenuation and deposition profiles, (4) unthermalized beam ion density and beam power density delivered to thermal plasma species from a numerical solution to the Fokker–Planck equation, (5) the neutral density profile, (6) local heat and particle transport coefficients consistent with the measured profiles and calculated source terms, (7) ICRF power profiles from a reduced order full wave analysis and isotropic Stix quasilinear model, and (8) total neutron emissivity and plasma stored energy. Several ion heat transport models (including neoclassical χi and χi∝χe) are available to calculate an expected Ti(r) profile in the absence of measurements.