PROTUBERANCES OF PLASMA PRESSURE CAUSED BY MODERATELY HIGH-POWER MICROWAVES IN A CORRUGATED WALL WAVE-GUIDE

Protuberances in the axial direction in an ion saturation current crea ted by microwave pulses externally injected into a plasma-filled corru gated wall waveguide are observed experimentally. This phenomenon is o bserved for moderately high microwave powers above a threshold value. Such protuberances are not observed in smooth cylindrical plasma waveg uides. Protuberances in the axial density profile and peaks in the sta nding waves of the axial RF electric field are always observed at iden tical axial positions, at which the radius of the corrugated wall is m inimum. A physical interpretation of the observed results is discussed in detail.