Pulsar radio emission mechanisms: a critique

Understand

We consider critically the three most widely favored pulsar radio emission mechanisms: coherent curvature emission (CCE), beam-driven relativistic plasma emission (RPE) and anomalous Doppler emission (ADE).

• We assume that the pulsar plasma is one dimensional (1D), streaming outward with a bulk Lorentz factor $\gamma_{\rm s} \gg \langle \gamma\rangle -1 \gtrsim 1$, where $\langle \gamma \rangle $ is the intrinsic spread in the rest frame of the plasma.
• We argue that the formation of beams in a multi-cloud model is ineffective in the intrinsically relativistic case for plausible parameters, because the overtaking takes too long.
• We argue that the default choice for the particle distribution in the rest frame is a J{\"u}ttner distribution and that relativistic streaming should be included by applying a Lorentz transformation to the rest-frame distribution, rather than the widely assumed relativistically streaming Gaussian distribution.