Experimental measurements of temperature from optical emission spectroscopy have been made on high power Argon transferred arcs with currents from 300 A to 800 A. Flow velocities at the axis were also measured from the
propagation of the perturbations on emitted light generated by the 300 Hz oscillation of the power source. From these experimental data we estimated the radial heat flux
and an effective heat diffusion coefficient. The comparison of these effective coefficients with the theoretical ones showed discrepancies when going to the edge of
the plasma column.