Abstract Experimental data on energy and impurity confinement times in the Ohmic heating mode of tokamaks of different sizes are reported. It is demonstrated that the results can be qualitatively explained by the reduction in the ratio of heat losses by electrons and ions upon an increase in the tokamak size. It is proposed to use this ratio for estimating the electron and ion energy confinement times in tokamaks in Ohmic regimes. The applicability of the proposed method in the modes with auxiliary heating requires further analysis. The measurement of the ratio of energy and impurity confinement times can be the only means of experimentally separating heat losses by electrons and ions in large tokamaks of reactor level.
V. A. Vershkov (Sun,) studied this question.