Density behavior during electron internal transport barriers in TCV fully non inductive discharges

Experimental results of particle transport during electron internal transport barriers (eITBs) achieved in the TCV device (Tokamak a Configuration Variable), in fully non inductive discharges, are shown. A database of steady state density profiles is constructed and studied in detail. An interesting relation between density and temperature scale lengths is observed. In the fully non inductive eITB scenario, the density profile is observed to develop a localized gradient, correlated via an almost constant factor with the electron temperature scale length up to the barrier foot. Sensitiveness of this behavior to the degree of the local confinement improvement is demonstrated by the study of the density response in eITBs with applied inductive current perturbations. The results shown have an impact also on the predictions about impurity transport in eITBs, and generally for fully non inductive operations in future machines.