Computer Simulation of Electron-Flow Bunching in the Pulsar Magnetosphere

Abstract

Bunch curvature emission is one of the well known pulsar radio emission mechanisms. The problem of bunch formation is very important for understanding the pulsar radio emission mechanism. In the axisymmetric pulsar magnetospheric bunching arises in the outflow channel as a result of interaction between moving electrons (DP) and captured ones (SP) (Rylov 1988). A numerical simulation was undertaken to determine how strongly the electron flow is bunched. The bunching appears to be very strong. It can be treated as a gas of electron bunches rather than small fluctuations of the electron flow. The thermal radio emission of the electron-bunch gas has a very high brightness temperature and sharp directivity. The power consumed in electron-bunch gas heating is sufficient to explain the pulsar radio emission. The pulsar radio emission mechanism appears to be thermal (the electron bunches move chaotically) and coherent (electrons of the bunch emit coherently) at the same time. For this reason the radio emission mechanism is very stable.