Wave propagation and damping in an electron cyclotron resonance plasma reactor

Propagation and damping of 2.45 GHz input microwaves in an electron cyclotron resonance (ECR) hydrogen plasma reactor were measured in a mirror magnetic field. Without plasma production the wave propagated in the chamber with a wavelength nearly equal to the one in a vacuum. When the hydrogen plasma was sustained at a pressure of 3.3×10−1 Pa, the wavelength was shortened to several cm and the wave was strongly damped near the resonance zone in the axial direction where the electron temperature as well as the plasma density indicated maximum values. The experimental result approximately agreed with the cold plasma dispersion relation for an electron cyclotron wave.