Pulsar radio emission

Pulsars sweep radio beams past us as they spin. What lets charged particles around the star produce such powerful radio waves?[1] [2]

A spinning pulsar produces radio pulses, but what makes its particles radiate collectively and lets the waves escape? In an ideal in-phase bunch of identical charges, radiation can reinforce; maintaining such coherence in a flowing electron–positron plasma is the unresolved step. One candidate, curvature emission, uses charges following curved magnetic field lines. Plasma-emission models instead amplify waves in the particle flow and require a route to escaping radiation.[1]

Different radiation mechanisms remain possible; knowing the beam’s motion does not identify its source.[1] [2]

Curvature and plasma-emission proposals face different constraints. The cited critique tests a particular streaming distribution; it does not exclude every realization of those mechanisms.[1]

The radio signal is one of our probes of the star’s surrounding particles and magnetic field. Understanding how it is made would help us interpret changes in pulse shape and polarization.[2]

Polarization depends on both the emission process and the plasma traversed by the waves. A physical model would help separate those effects when radio data are used to infer an unseen magnetic geometry and particle environment.[2]