Formation of "Lightnings" in a Neutron Star Magnetosphere and the Nature of RRATs

TL;DR

This paper explores how lightning-like discharges in neutron star magnetospheres, caused by cosmic gamma-ray photons, could explain the radio bursts observed in RRATs, linking these phenomena to pulsars and nullers.

Contribution

It proposes a model connecting neutron star magnetospheric lightning formation with RRAT radio bursts, providing explanations for burst intervals and widths consistent with observations.

Findings

Lightning length up to 1000 km

Typical burst interval ~100 seconds

Radio burst width determined by emission cone and lightning lifetime

Abstract

The connection between the radio emission from "lightnings" produced by the absorption of high-energy photons from the cosmic gamma-ray background in a neutron star magnetosphere and radio bursts from rotating radio transients (RRATs) is investigated. The lightning length reaches 1000 km; the lightning radius is 100 m and is comparable to the polar cap radius. If a closed magnetosphere is filled with a dense plasma, then lightnings are efficiently formed only in the region of open magnetic field lines. For the radio emission from a separate lightning to be observed, the polar cap of the neutron star must be directed toward the observer and, at the same time, the lightning must be formed. The maximum burst rate is related to the time of the plasma outflow from the polar cap region. The typical interval between two consecutive bursts is ~100 s. The width of a single radio burst can be determined both by the width of the emission cone formed by the lightning emitting regions at some height above the neutron star surface and by a finite lightning lifetime. The width of the phase distribution for radio bursts from RRATs, along with the integrated pulse width, is determined by the width of the bundle of open magnetic field lines at the formation height of the radio emission. The results obtained are consistent with the currently available data and are indicative of a close connection between RRATs, intermittent pulsars, and extreme nullers.