[en] In order to understand plasma processes and to obtain technological control in thin film deposition, the study of surface-plasma interactions is essential. Apart from the type and flux of the impinging ions/neutral atoms on the surface, the ion energy distribution (IED) is an important parameter in understanding surface modification due to the plasma. In this paper, results of ion energy analysis of the Thermionic Vacuum Arc (TVA) plasma ignited in carbon vapours are presented. An in-house, computer-controlled retarding field analyzer was used for determining experimentally ion energy distributions of the carbon ions arriving at the substrate. The correlation of the carbon IED with the applied arc voltage in the TVA plasma was put in evidence for the first time.