Based on the extended spectroscopic investigations and high-speed visualization of the plasma filament, the view is justified that the near cathode region of atmospheric pressure electric arcs with current densities of 2 kA/cm2 and above in vortex stabilized plasmatrons with a divergent channel hold much promise for various metrological purposes. The developed automated system allows a diverse body of spectroscopic information to be rapidly processed, thus making possible setting up extensive databases on spectral characteristics of heated gases. The thermodynamic state of the generated plasmas is analyzed; the difference between the electron temperature and that of heavy species is estimated. Arguments are advanced in favour of the considered plasmas to be in a partial LTE. The quasi-stationary and local approximations are shown to hold.