Range of existence of self-sustained, subcritical microwave streamer discharges

Data are presented from a study of subcritical microwave streamer discharge s in air in an electromagnetic beam. It is shown that, depending on the deg ree of subcriticality, this kind of discharge can have two forms: a self-su stained discharge and a discharge that is attached to the initiating trigge r. The range of subcriticality for the initial field is determined as a fun ction of air pressure within which the self-sustained developed discharge f orm exists. (C) 1999 American Institute of Physics. [S1063-7842(99)00411-0] .