Discussion of radiative-transfer methods applied to electromagnetic reflection from turbulent plasma

The reflected energy flux of electromagnetic waves incident upon an underdense turbulent plasma recently has been extended beyond the weak-scattering Born approximation by two different methods. One approach is based upon summing cumulative small-angle propagation effects between successive large-angle scatterings. A heuristic application of radiative-transfer methods under the same approximations and conditions yields a backscatter cross section that differs by a factor of up to one-half at given plasma thickness. It is shown that the cross section can be made to agree with that of the selective-summation approach by including a class of contributions that appears to have been omitted in the radiative-transfer approach.