Microwave Absorption by a Plasma Slab

抄録

The reflected power of microwave is experimentally examined, when the wave is incident on a plasma slab with a metal wall at its rear side. From the reflected power, it is found that the power is dissipated most effectively under a certain condition. This condition calculated with approximations is confirmed to be satisfactory in comparison with the experimental results.
An afterglow plasma produced by repeated pulses of high DC voltage in a part of an X-band rectangular waveguide is used as a plasma slab with electrons uniformly distributed. The collision frequency of electrons with ions which predominates over that with neutral atoms in the afterglow plasma during the time of interest is determined at the maximum absorption. The collision frequency found is slightly higher than that predicted by the theories of various authors and fairly agrees with the result previously measured by a different microwave method. The electron temperature can be estimated from the reflected power at the maximum absorption.