The decay of the plasma produced by a freely localized microwave discharge

A freely localized discharge is excited by a powerful microwave beam in argon, hydrogen and nitrogen. All processes of gas discharge production, maintenance and decay are volumetric in nature. The plasma decay is determined by diagnostic microwave beam attenuation. In the initial post-discharge stage the decay is close to an exponential law in nitrogen and hydrogen and to a linear law in argon. The decay adheres to the 'recombinational' law only during the final stage of relaxation. Possible mechanisms for such behaviour are discussed.