Propagation in Plasmas along the Magnetic Field I. Circular Polarization

Abstract

A carefully designed experiment has been conducted in which the propagation of circularly polarized plane waves through a helium plasma along the direction of a static magnetic field has been quantitatively investigated. Determination of electron densities from independent measurements using the left-hand and right-hand circularly polarized wave modes show excellent agreement with each other and with theory over all ranges of magnetic fields. Attenuation measurements also agree well with theory, except when the cyclotron frequency exceeds the radio frequency for the right-hand mode, the dependence of the collisional effects on electron velocity should be included in the analysis. The regions of the parameters where boundary effects are important can also be ascertained from the measurements.