Determination of the density of preionization electrons in the active medium of a CO2 laser

The density of electrons created by microwave preionization in CO₂, N₂, He, and their mixtures was determined in the pressure range 4–27 kPa. When the energy deposited in the active medium was low (from 0.04 to 0.4 J per pulse), the electron density ranged from 2×10⁷ to 10¹⁰ cm^–3 in a chamber of 0.2-liter volume.