Soviet Physics Journal. Kluwer Academic Publishers-Plenum Publishers. Vol. 28. 1985. P. 961-964
It is shown that a circularly polarized electromagnetic wave with frequency omega 0 near the electron plasma frequency propagating along a DC magnetic field decays into a Langmuir wave and a circularly polarized Alfven wave. It is found that the pump and Alfven waves have the same helicity. Explicit expressions for the growth rate and threshold are obtained.