  We present the numerical simulations of coherent inverse Compton scattering
(CICS) in a highly magnetized plasma process by means of a full three
dimensional particle in cell code (PIC), which is mass and energy conservative.
We used the parameters of a pulsar magnetosphere where CICS is one of the most
promising models for the generation of the observed highly coherent radio
emission. First we show details of the onset and time evolution of strong
Langmuir turbulence driven by a relativistic electron beam penetrating a
strongly magnetized background plasma. The Langmuir turbulence acts as
self-generated wiggler fields which bunch the beam electrons thereby inducing
strong coherent emission of the bunches at frequency gamma^2 times the plasma
frequency. The emitted power is about 10 GW in a few nanoseconds. This
radiation is interpreted in terms of inverse Compton scattering on nonlinear
density fluctuations. CICS is the longitudinal version of a laboratory free
electron laser and is applicable in strongly magnetized plasmas like pulsars.
