Geometrical effects in X-mode scattering

One technique to extend microwave scattering as a probe of long-wavelength density fluctuations in magnetically confined plasmas is to consider the launching and scattering of extraordinary (X-mode) waves nearly perpendicular to the field. The geometrical factor is calculated for the special case of scattering perpendicular to the magnetic field. For frequencies above the ordinary-mode cut-off the scattering is relatively isotropic, while below cut-off there are minima in the forward and backward directions which go to zero at approximately half the ordinary-mode cut-off density. (author)