A comparison of the oscillating mirror and Bragg resonance pictures of fluctuation reflectometry in one-dimensional plasmas (abstract)

We have computed the amplitude and phase responses of microwaves scattered from fluctuation wave packets that stream down a density gradient. At various wavelengths and packet sizes and shapes, the dominant scattered signal is either due to reflection from the critical surface or due to Bragg resonance scattering from below the critical density. Depending on the amplitude and wavelength of the fluctuation, one or both of these mechanisms might play a role. The delineation of their relative importance is carried out. Comparisons are made to previous studies within and beyond the Born approximation.1,2 The motivation for this work is a series of well-controlled experiments carried out by the plasma diagnostics group at UC Davis. We will show comparisons of our numerical results, using their experimental parameters, with their measurements of scattered microwave amplitude and phase.3 copyright 1997 American Institute of Physics