Production of a sheet plasma distribution for reflection of high frequency microwaves

Summary form only given. The Agile Mirror experiment at the Naval Research Laboratory has produced a planar 60/spl times/60 cm plasma mirror capable of reflecting 10 GHz microwaves. The plasma distribution is produced in a low pressure chamber in a 200 Gauss magnetic field. The mirror turns on or off in <10 /spl mu/sec and has been maintained for up to 10 msec. A microwave beam reflected 90 degrees has a very similar far field radiation pattern as one reflected by a metal plate and is comparable to the radiation pattern produced by the illuminating dish alone. The plasma distribution is initiated with a 3-5 kV voltage pulse which drives an abnormal glow discharge between a linear hollow cathode and a planar anode. The high density plasma in the negative glow region of the discharge is maintained by the high energy electrons emitted from the cathode. A detailed picture of the understanding of how the mirror is formed and its evolution is presented. Initial efforts at making the mirror agile by designating different cathode orientations and by modifying the magnetic field geometry are described.