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Using a relativistic plasma with an isotropic monoenergetic distribution of electrons and positrons as an example, we show that in the maser regime the maximum possible amplification of synchrotron radiation at a distance of one wavelength is achieved in a medium where the magnetic energy density is of the order of the particle energy density. This ratio of the energy densities corresponds to a (Harris-type) current sheet. We have obtained an electron Lorentz factor of 350 and a magnetic field strength of 10 kG in the maser radio emission region for the Crab pulsar. Our estimate suggests that the optical and coherent radio emissions of the object originate from one synchrotron source in the form of a current sheet. The diameter of the source must exceed the light-cylinder radius approximately by a factor of 6 for the maser wave field to interact with particles in the linear regime, in particular, to keep its phase velocity higher than the speed of light in a vacuum—a necessary condition for the synchrotron instability. [ABSTRACT FROM AUTHOR]

The pulsar J0901–4046 has a spin period s and is the most slowly rotating one among the isolated radio pulsars. We have considered the influence of a small-scale magnetic field in the off-centered dipole model on the polar cap heating by the reverse positron current in the inner gap of the pulsar. We have assumed that the electron–positron pairs in the gap are created in bound states, which then are broken by thermal photons from the stellar surface. [ABSTRACT FROM AUTHOR]

We consider the evolutionary status of the recently discovered long-period radio sources PSR J0901-4046, GLEAM-X J1627-52, and GPM J1839-10. It is hypothesized that all three sources are radio pulsars. Within the framework of standard scenarios, it is thought that for the pulsar mechanism to operate, it is necessary to exclude the penetration of external matter into the light cylinder, which corresponds to the ejector stage. We show that for realistic properties of the interstellar medium the 76-second pulsar J0901-4046 must be at this stage, whereas the sources GLEAM-X J1627-52 and GPM J1839-10 with periods s can be at this stage only in the case of unrealistically high dipolar magnetic fields G. We also show that sources with periods s and magnetic fields G cannot be ejectors in a realistic interstellar medium. Thus, we predict that long-period radio pulsars with standard magnetic fields will not be discovered. [ABSTRACT FROM AUTHOR]

The birth function of neutron stars in magnetic field is estimated for two models of the evolution of radio pulsars corresponding to different directions of evolution of the inclination angle of the magnetic axis to the rotation axis (toward small angles or angles close to ). We show that for both models at magnetic fields G it is a power law with a break near G. At the same time, however, the number of born pulsars with a super-strong magnetic field G in the first model turns out to be smaller than that in the second one by an order of magnitude. [ABSTRACT FROM AUTHOR]

The X-ray luminosity and temperature of the polar cap heated by the back flux of positrons from a radio pulsar with a period P ∼ 1 s and a magnetic field B ~ 10 G have been estimated. An additional source of X-ray emission-a thin, hotter semiring on the polar-cap periphery-is shown to also exist. It is heated by the back flux of electrons from the light cylinder. Furthermore, the electric field near the hot semiring accelerates the ions of the surface layer that leave the neutron-star magnetosphere. The semiring area is smaller than the polar-cap area approximately by a factor of 100, i.e., at the same luminosity the temperature is higher by a factor of 3. The observed X-ray emission from old radio pulsars is the emission from thin hot polar-cap semirings. The emission from the polar caps themselves is strongly attenuated by interstellar absorption. [ABSTRACT FROM AUTHOR]

Using a well-known method for calculating the propagation of waves in an inhomogeneous medium, we have managed to reduce the problem of wave propagation in pulsar magnetospheres to a system of two ordinary differential equations that allow the polarization characteristics of the radio emission to be quantitatively described for any magnetic field structure and an arbitrary density profile of the outflowing plasma. We confirm that for ordinary pulsars (period P ∼ 1 s, magnetic field B0 ∼ 1012 G, particle production multiplicity parameter λ ∼ 104), the polarization is formed inside the light cylinder at a distance of the order of a thousand neutron star radii. For reasonable magnetic field strengths and plasma densities on the emission propagation path, the degree of circular polarization is found to be ∼5–20%, in good agreement with observations. [ABSTRACT FROM AUTHOR]

We analyze the statistical distribution of neutron stars at the stage of a supersonic propeller. An important point of our analysis is allowance for the evolution of the angle of inclination of the magnetic axis to the spin axis of the neutron star for the boundary of the transition to the supersonic propeller stage. We have determined the spin period distributions of pulsars at the propeller stage for two models: the model with hindered particle escape from the stellar surface and the model with free particle escape. As a result, we have shown that consistent allowance for the evolution of the inclination angle in the region of extinct radio pulsars for the two models leads to an increase in the total number of neutron stars at the supersonic propeller stage. This increase stems from the fact that when allowing for the evolution of the inclination angle χ for neutron stars in the region of extinct radio pulsars and, hence, for the boundary of the transition to the propeller stage, this transition is possible at shorter spin periods (P ∼ 5–10 s) than assumed in the standard model.© 2005 Pleiades Publishing, Inc. [ABSTRACT FROM AUTHOR]

We study the statistical distribution of extinct radio pulsars at the stage of an ejector. An important element that distinguishes our study from other works is a consistent allowance for the evolution of the angle of inclination of the magnetic axis to the spin axis. We determined the distribution of extinct radio pulsars in spin period for two models: the model with hindered particle escape from the neutron-star surface and the model with free particle escape. The total number of extinct radio pulsars is shown to be much smaller than that in the model in which the evolution of the angle of axial inclination is disregarded. This is because when the evolution of the angle of axial inclination is taken into account, the transition to the stage of a propeller occurs at much shorter neutron-star spin periods (P ∼ 5–10 s) than assumed previously.© 2005 Pleiades Publishing, Inc. [ABSTRACT FROM AUTHOR]