Comparison of Measured and Theoretical Inverse Bremsstrahlung and Photoionization Absorption of Infrared Radiation in a H-He Plasma

The absorption coefficients of 1.15- and 3.39-{μ}m radiation for a homogeneous H-He plasma have been measured in the temperature range 14×10³<~T<~20×10³^∘K and electron density range 8×10¹⁶<~nₑ<~5×10¹⁷ cm^-3, where the major absorption mechanisms are electron-ion inverse bremsstrahlung and neutral-atom photoionization. The measured values compare well with those obtained from theoretical calculations for a gas in thermodynamic equilibrium.