Characteristics of the toroidal ITG-instability are analysed for conditions of the L-mode and the radiatively improved (RI) mode triggered in TEXTOR-94 by puffing of neon. Analysis is performed for experimentally measured profiles of the plasma parameters and densities of impurity species. It is shown that in the RI-mode the anomalous transport induced by this kind of instability is reduced significantly in a large part of the plasma volume. This is an important channel of the energy confinement improvement. The role of the radial electric field is envisaged.
MHD activity at the beta limit in RI mode discharges on TEXTOR-94