Spatial distributions of the effective electron temperature (T-eff) and plasma potential were studied from the measurement of an electron energy probability function in a side type ferrite-core inductively coupled plasma with an argonehelium-mixture. As the helium gas was diluted at the fixed total gas pressure of 5 mTorr in an argon discharge, the distribution of the plasma density and plasma potential changed from a concave to a flat profile, and finally became a convex profile, while all spatial profiles of T-eff were hollow shapes with helium dilution in the argon discharge. This evolution of the plasma potential with helium gas could be explained by the increased energy relaxation length (lambda(e)), indicating the transition of electron kinetics from local to non-local kinetics. (C) 2015 Elsevier B.V. All rights reserved.