Abstract
We classify the incoherent laser Thomson scattering (LTS) diagnostics of plasmas for measurements of electron density ne and temperature Te (or more generally electron energy distribution functions;EEDFs) as having evolved from the first stage, in which a whole Thomson spectrum is obtained during a single laser pulse from plasmas having ne above 1018 m-3, through the second stage, in which data accumulation is prerequisite for ne below 1018 m-3, and to the third stage, in which measurements from a material surface as close as a few tens of μm is required. In this last case, a strong suppression of stray light in addition to the data accumulation is necessary, and this was first demonstrated for a PDP (plasma display panel)-like discharge in 2000. In order to further expand its applicable range, we have been pursuing a more systematic approach, taking into account factors such as laser propagation⁄profile control, further stray light suppression, and other aspects. In this review article, we describe these developments and discuss future plans.
