  We demonstrate that nonlinear decay of obliquely propagating Langmuir waves
into Langmuir and Alfven waves (L --> L'+A) is possible in a one-dimensional,
highly relativistic, streaming, pair plasma. Such a plasma may be in the
magnetospheres of pulsars. It is shown that the characteristic frequency of
generated Alfven waves is much less than the frequency of Langmuir waves and
may be consistent with the observational data on the radio emission of pulsars.
