This paper investigates the stability of intense optical slab beams in infinite plasmas. Profiles depending on the distance x were found in a recent paper by Kurki-Suonio, Morrison, and Tajima [Phys. Rev. A 40, 3230 (1989)]. The most useful profiles were in the form of solitons. Solutions for which the beam profile was of oscillatory character were also found. Here a stability analysis is performed on all these profiles. The results, in terms of the physical cylindrical variables, imply radial stability but azimuthal instability of the solitons. The wave structures, however, are also unstable in the radial direction, and this explains numerical results of Kurki-Suonio et al.

• Received 4 December 1989

DOI:https://doi.org/10.1103/PhysRevA.42.1005