Measurement of localized electrostatic oscillations excited by low-power microwaves in a plasma waveguide

Localized electron plasma oscillations excited at the resonant surface by low-power microwaves incident obliquely on an inhomogeneous unmagnetized plasma in a cylindrical waveguide are measured by a receiving antenna. The disturbance by the antenna on the electrostatic fields is significantly reduced in our condition with a steep density gradient and large angles of incidence. As a result, patterns of large and broad resonance field including phase information are observed. The peak values of the resonantly excited field are compared with numerical analyses. (author)