Microwave reflectometry for magnetically confined plasmas

This article is about microwave reflectometry-a radar technique for plasma density measurements using the reflection of electromagnetic waves by a plasma cutoff. Both the theoretical foundations of reflectometry and its practical application to the study of magnetically confined plasmas are reviewed in this article. In particular, the role of short-scale density fluctuations is discussed at length, both as a unique diagnostic tool for turbulence studies in thermonuclear plasmas, and for the deleterious effects that fluctuations may have on the measurement of the average plasma density with microwave reflectometry. (C) 1998 American Institute of Physics. [S0034-6748(98)05906-1].