The computer animation illustrates the geometries described in a paper by the same authors The preprint is available as number 9401045 The opening scene shows dipole field lines emanating from the polar caps of a rotating neutron star The dipole axis is inclined along the green rods The field lines shown are defined from the condition that they be tangent to the light cylinder (the cylindrical radius at which the tangential velocity of rotation reaches the speed of light) The static dipole field lines are smoothly morphed into the correct retarted-potential vacuum solutions A red surface spanning these field lines is painted In the next scene the blue surfaces represent the outer gaps above the surface of last closed field lines High energy emission (blue) is produced in these outer gaps, and is beamed tangentially along the field lines The radio emission (green) originates close to the surface of the star and is beamed along the dipole axes The inclination angle $\alpha$ of the dipole and the viewing angle $\zeta$ are chosen to match the Crab parameters; $\alpha$ = 70, $\zeta$ = 65 The corresponding light curve is computed and shown for these angles, and the red dot traces rotation phase The next scene shows the situation for angles appropriate to PSR1706-44; $\alpha$ = 45, $\zeta$ = 65 The final scene is a possibility for Geminga; $\alpha$ = 20, $\zeta$ = 75 These angles are poorly constrained as there is no radio emission

$\gamma$-Ray Pulsars: Emission Zones and Viewing Geometries, A Computer Animation

Abstract Galactic cosmic rays consist of primary and secondary particles. Primary cosmic rays are thought to be energized by first order Fermi acceleration processes at supernova shock fronts within our Galaxy. The cosmic rays that eventually reach the Earth from this source are mainly protons and atomic nuclei, but also include electrons. Secondary cosmic rays are created in collisions of primary particles with the diffuse interstellar gas. They are relatively rare but carry important information on the Galactic propagation of the primary particles. The secondary component includes a small fraction of antimatter particles, positrons and antiprotons. In addition, positrons and antiprotons may also come from unusual sources and possibly provide insight into new physics. For instance, the annihilation of heavy supersymmetric dark matter particles within the Galactic halo could lead to positrons or antiprotons with distinctive energy signatures. With the High-Energy Antimatter Telescope (HEAT) balloon-borne instrument, we have measured the abundances of positrons and electrons at energies between 1 and 50 GeV. The data suggest that indeed a small additional antimatter component may be present that cannot be explained by a purely secondary production mechanism. Here we describe the signature of the effect and discuss its possible origin.

Cosmic-Ray Positions: Are there Primary Sources?

High-energy radiation from pulsars: a three-dimensional model approach

Aerosol manipulation through modulated multiple acoustic wavepackets with a pair of resonators

We re-study the one-dimensional electric held structure of an Outer gap accelerator by considering the physical limit of trans-field height. Inside the outer gap, the charge depletion creates a large electric held along the magnetic held lines. Electrons and/or positions are accelerated to ultra-relativistic energies by this longitudinal electric held, and then radiate gamma-ray photons by curvature radiation. The collision of these gamma-rays and ambient x-ray photons further produce radiating particles, resulting in a stationary gap. We solve the structure of this longitudinal electric held together with the distributions of elections and positions and gamma-ray photons for an aligned rotator. Our results indicate that the outer gap can extend to the light cylinder using reasonable parameters.

https://iopscience.iop.org/article/10.1088/0256-307X/23/10/070/pdf

One-Dimensional Electric Field Structure of an Outer Gap Accelerator

In the frame of the gamma -ray pulsar outer gap model, e(+/-) pairs in the pulsar magnetosphere are produced by the cascade of e(+/-) pairs through synchrotron radiation of the return current fi om the outer gap. These pairs are accelerated mono-energetically to relativistic energies in the pulsar wind driven by low-frequency electromagnetic waves. Using Monte Carlo simulations, we generate a sample of the mature gamma -ray pulsars in our Galaxy and calculate the positron production rate from these pulsars. With a simple leaky box model, we calculate the ratio of cosmic-ray positron to total electrons. Our result indicates that the pulsar contribution to the cosmic-ray positron peaks at about 40 GeV and the observed e(+)/(e(-) + e(+)) ratio can be explained by this model.

Cosmic-ray positrons produced by pulsar winds from mature gamma-ray pulsars

We use a three-dimensional pulsar magnetosphere model to study the light curve and spectra of x-rays and gamma-rays from the Crab pulsar. In this model, the vertical size of the outer gap is first determined by a self-consistent model in which the outer gap is limited by pair production from collisions of thermal photons produced by polar cap heating of backflow outer gap current and curvature photons emitted by gap accelerated charged particles. The transverse size of the outer gap is determined by local pair production conditions. In principle, there are two topologically disconnected outer gaps present in the magnetosphere of a pulsar, and both incoming and outgoing particle flows are allowed. However, double-peak light curves with strong bridges are most common, Making use of the three-dimensional structure of the outer gap and its local properties, we compare the results of our model with the light curve and phase-resolved spectra of the Crab pulsar.

On the light curve and spectra of x-rays and gamma-rays from the Crab pulsar

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Cosmic-ray positrons produced by pulsar winds from mature gamma-ray pulsars

On the light curve and spectra of x-rays and gamma-rays from the Crab pulsar