Transport studies in the TJ-I tokamak from steady and perturbative methods

Transport analysis in the steady state and the natural perturbation of the sawteeth observed in electron temperature and density measurements in ohmic discharges of the TJ-I tokamak are used for studying the dependence of particle and electron energy fluxes on density and temperature gradients. The results of coupled analysis for propagation of density and temperature perturbations give a transport coefficient matrix with negligible off-diagonal terms. The effective electron heat conductivity chi is one order of magnitude greater than the effective particle diffusion coefficient D. The heat conductivity obtained from heat pulse measurements is close to that obtained from power balance analysis. The diffusion coefficient from density pulses is also close to that obtained from steady state analysis assuming a neoclassical inward pinch. A strong relationship of the deduced heat conductivity with q profile was found, which can be interpreted as due to tearing modes. A unified expression for particle and energy fluxes, which explains the results of pulse propagation and steady state profiles, is also given