The effect of plasma density profile on the backscatter of microwaves from a plasma-covered plane conductor

Summary form only given. In order to gain insight into the mechanism of anomalous absorption of microwaves in a pulsed plasma column, the latter was studied using single and double Langmuir probes. Graphs of plasma potential recorded by floating Langmuir probes as a function of time were obtained for a range of pressure of the background gas and at different distances from the plasma-covered plane-conducting plate. From these data, two main components of the plasma have been identified. The first appears earlier, exhibits greater fluctuations, and is shorter in duration than the second component. The presence of these components is consistent with earlier observations obtained from transverse transmission measurements of microwaves through the plasma. Microwave backscatter measurements under varying conditions of plasma-density profile and ambient gas pressure have also been performed.