Spectrographic techniques have been used to determine electron temperatures and densities in the interelectrode plasma of a close‐spaced high‐current cesium plasma diode. These results were obtained from the relative intensity of the radiative recombination continuum and measured line‐widths, respectively, of cesium. The diode was operated at two short‐circuit current conditions (∼15 and 18 A/cm2) with an interelectrode spacing of 0.25 mm. Contrary to some theories, these results indicate that steep temperature gradients do exist in the plasma and that maximum electron temperatures are 2800°K.