Full-wave test of the radial correlation reflectometry analytical theory in linear and nonlinear regimes

Full-wave 1D simulations of fluctuation reflectometry are compared with the nonlinear theory recently published (Gusakov et al 2002 Plasma Phys. Control. Fusion 44 2327), for the case of time-independent turbulence, as well as for the case of space-time turbulence. Homogeneous and inhomogeneous turbulence models are considered. The simulations confirm quantitatively predictions of both linear and nonlinear theory for the correlation time and correlation length of the signal. The localization properties of the signal in the nonlinear regime are also found to be in good agreement with theory. Whereas the correlation time of the signal depends on the turbulence all over the plasma, its correlation length is essentially driven by the turbulence in the close vicinity of the cut-off. It turns out that theory gives a value of the correlation length within a factor of 2 even for turbulence levels as high as 20%, well beyond its validity domain.