Relativistic Corrections to Microwave Interferometry in Plasmas

The index of refraction for a plasma with a high electron temperature was calculated for plane, transverse waves having frequencies large compared to the plasma frequency and to the electron cyclotron frequency. Results indicate that microwave phase-shift measurements of the plasma density based on the cold plasma relation for the index of refraction tend to be too small at high temperatures (T > mc/sup 2/). (R.E.U.)