Fluctuation reflectometry of azimuthally symmetric plasmas

Bruskin, L. G.; Mase, Atsushi*; Oyama, Naoyuki; Miura, Yukitoshi

The results of analytical solution of time-dependent 2D full-wave equation are presented here for the case of fluctuation reflectometry. We consider a family of plasma density profiles with cylindrical symmetry, which allow for an integration of the microwave scattering equation. Based on the results of analytical modeling, Doppler reflectometry as a method of plasma velocity measurements is investigated. It is shown that the accuracy of Doppler shift measurements is sensitive to the spectral content of the broadband turbulence, as well as to the curvature of the plasma cut-off layer. Addressing the problem of fluctuation amplitude measurements, it is suggested that a power-related parameter of the microwave signal, called fluctuation index, is suitable to quantify the plasma turbulence level provided that the fluctuation spectrum is a priori estimated.