  It is shown that pulsar radio emission can be generated effectively through a
streaming motion in the polar-cap regions of a pulsar magnetosphere causing
nonresonant growth of waves that can escape directly. As in other beam models,
a relatively low-energy high-density beam is required. The instability
generates quasi-transverse waves in a beam mode at frequencies that can be well
below the resonant frequency. As the waves propagate outward growth continues
until the height at which the wave frequency is equal to the resonant
frequency. Beyond this point the waves escape in a natural plasma mode (L-O
mode). This one-step mechanism is much more efficient than previously widely
considered multi-step mechanisms.
