Plasma diagnostics by the Schlieren method in the submillimeter wavelength range

The Schlieren method and an HCN laser (λ=337 μ) were used in the determination of the spatial distribution of the electron density N_e in the plasma of a carbon arc, whose jet was in the form of an elliptic cylinder. The maximum and average values of N_e in the central plane were 3×10¹⁴ and (0.4–1.0)×10¹⁴ cm^–3, respectively.