Interaction of Beams of Radiation of Finite Diameters within a Plasma

Two beams of waves of finite diameters intersecting within a magnetized plasma emit a secondary beam of waves, provided a resonance condition is satisfied. The field of the secondary beam and the total power emitted are determined for arbitary directions and polarizations of the incident beams. This process could be used as a means of time- and space-resolved diagnostics since it yields two relations between the density, the temperatures, and the magnetic field. Explicit formulas are given for the case of two beams in the ordinary mode producing a lower hybrid wave.