We have studied the relation of the energy‐loss rate and the enhanced diffusion with the amplitude of spontaneously excited low‐frequency plasma oscillation in a current‐carrying argon plasma. The experimental results (radial distributions of the electron density, electric floating potential, and electric field) and the theoretical model that is developed showed the important role of the low‐frequency plasma oscillations on the additional power losses of the plasma. Also, the energy‐loss rate has been studied as a function of the plasma radius.