Related papers: Photon Splitting and Pair Creation in Highly Magne…
The complete absence of radio pulsars with periods exceeding a few seconds has lead to the popular notion of the existence of a high $P$ death line. In the standard picture, beyond this boundary, pulsars with low spin rates cannot…
The complete absence of radio pulsars with periods exceeding a few seconds has lead to the popular notion of the existence of a high period death line. We have recently postulated the existence of another radio quiescence boundary at high…
In the hot environments of the anomalous X-ray pulsars and the soft gamma-ray repeaters, as indicated by their luminous, pulsed, quiescent X-ray emission, $\gamma$-rays generated from the inner gaps may have shorter attenuation lengths via…
Pulsar radio emission is believed to be originated from the electron-positron pairs streaming out from the polar cap region. Pair formation, an essential condition for pulsar radio emission, is believed to be sustained in active pulsars via…
Magnetic photon splitting, a QED process that becomes important only in magnetic fields approaching the quantum critical value, B_cr = 4.41 X 10^13 Gauss, is investigated as a mechanism for attenuation of gamma-rays emitted near the surface…
In this paper, which is the first in a series of papers devoted to a detailed analysis of the death line of radio pulsars, we consider a possibility of producing secondary particles at a sufficiently long pulsar period P. To this end, we…
The notable absence of radio pulsars having measured magnetic dipole surface field strengths above $B_0\sim 3\times 10^{13}$ Gauss naturally raises the question of whether this forms an upper limit to pulsar magnetization. Recently there…
Motivated by the recent detection of ultra-long period radio transients, we investigate new models of coherent radio emission via low-altitude electron-positron pair production in neutron stars beyond rotationally-powered curvature…
Developments over the last couple of years have supported the interpretation that anomalous X-ray pulsars (AXPs) and soft gamma repeaters (SGRs) possess unusually high magnetic fields, and furthermore may represent a class or classes of…
Photon splitting is a QED process that can potentially suppress pair production in the inner magnetosphere of a pulsar with a super-strong magnetic field, and hence, may quench radio emission from these objects. While it is unknown how many…
We present numerical simulations of electron-positron pair cascades in the magnetospheres of magnetic neutron stars for a wide range of surface fields (B_p = 10^{12}--10^{15} G), rotation periods (0.1--10 s), and field geometries. This has…
Gamma-rays from pulsars can be efficiently attenuated in their magnetospheres via the mechanism of single-photon pair production and also the exotic QED process of photon splitting, which become prolific in fields approaching the quantum…
Recent advances in numerical algorithms and computational power have enabled first-principles simulations of pulsar magnetospheres using Particle-in-Cell (PIC) techniques. These ab-initio simulations seem to indicate that pair creation…
We investigate the conditions required for the production of electron-positron pairs above a pulsar polar cap (PC) and the influence of pair production on the energetics of the primary particle acceleration. Assuming space-charge limited…
We analytically investigate the condition for a particle accelerator to be active in the outer magnetosphere of a rotation-powered pulsar. Within the accelerator (or the gap), magnetic-field-aligned electric field accelerates electrons and…
In the framework of the coherent curvature radiation model of pulsar radio emission, charged particles responsible for the radio emission are generated on the polar cap in the localized pair cascade processes called sparks. When a pulsar…
For axions that couple to nucleons, the presence of dense nuclear matter can displace the axion from its vacuum minimum, sourcing large field gradients around neutron stars (and, more generally, compact objects). These gradients, which we…
Over the last four decades, persistent and flaring emission of magnetars observed by various telescopes has provided us with a suite of light curves and spectra in soft and hard X-rays, with no emission yet detected above around 1 MeV.…
In this paper, which is the second in a series of papers, we analyse what parameters can determine the width of the radio pulsar 'death valley' in the $P$-${\dot P}$ diagram. Using exact expression for the maximum potential drop, which can…
We investigate the physical situation above the pulsar polar cap (PC) where the accelerating primaries (electrons) are not capable of producing sufficient numbers of electron-positron pairs at low altitudes (within 1-2 stellar radii above…