scholarly journals Multipolar electromagnetic fields around neutron stars: exact vacuum solutions and related properties

2015 ◽  
Vol 450 (1) ◽  
pp. 714-742 ◽  
Author(s):  
J. Pétri
Keyword(s):  
Neutron Stars ◽  
Electromagnetic Fields ◽  
Vacuum Solutions

Photoproduction of gravitational radiation by some astrophysical objects

1976 ◽  
Vol 54 (1) ◽  
pp. 76-79 ◽  
Author(s):  
G. Papini ◽  
S.-R. Valluri
Keyword(s):  
Neutron Stars ◽  
Electromagnetic Fields ◽  
Gravitational Radiation ◽  
Galactic Center ◽  
Seyfert Galaxies ◽  
The Sun ◽  
Ngc 4151 ◽  
Astrophysical Objects ◽  
Ngc 1068

Estimates are given for the amounts of gravitational radiation produced in the interaction of photons with the static electromagnetic fields of some astrophysical objects. These are the Sun, Quasar 3C273, Seyfert galaxies NGC 1068 and NGC 4151, the Galactic Center, and neutron stars.

scholarly journals A relativistic particle pusher for ultra-strong electromagnetic fields

2020 ◽  
Vol 86 (4) ◽  
Author(s):  
J. Pétri
Keyword(s):  
Neutron Stars ◽  
Electromagnetic Fields ◽  
Electromagnetic Waves ◽  
High Energy Physics ◽  
Exact Analytical Solution ◽  
Lorentz Factor ◽  
High Energy ◽  
Compact Objects ◽  
Intense Laser ◽  
Time Step

Kinetic plasma simulations are nowadays commonly used to study a wealth of nonlinear behaviours and properties in laboratory and space plasmas. In particular, in high-energy physics and astrophysics, the plasma usually evolves in ultra-strong electromagnetic fields produced by intense laser beams for the former or by rotating compact objects such as neutron stars and black holes for the latter. In these ultra-strong electromagnetic fields, the gyro-period is several orders of magnitude smaller than the time scale on which we desire to investigate the plasma evolution. Some approximations are required such as, for instance, artificially decreasing the electromagnetic field strength, which is certainly not satisfactory. The main flaw of this downscaling is that it cannot reproduce particle acceleration to ultra-relativistic speeds with a Lorentz factor above $\gamma \approx 10^3$ – $10^4$ . In this paper, we design a new algorithm able to catch particle motion and acceleration to a Lorentz factor of up to $10^{15}$ or even higher by using Lorentz boosts to special frames where the electric and magnetic field are parallel. Assuming that these fields are locally uniform in space and constant in time, we solve analytically the equation of motion in a tiny region smaller than the length scale of the spatial and temporal gradient of the field. This analytical integration of the orbit severely reduces the constraint on the time step, allowing us to use large time steps, avoiding resolving the ultra-high gyro-frequency. We performed simulations in ultra-strong spatially and time-dependent electromagnetic fields, showing that our particle pusher is able to follow accurately the exact analytical solution for very long times. This property is crucial to properly capture for instance lepton electrodynamics in electromagnetic waves produced by fast rotating neutron stars. We conclude with a simple implementation of our new pusher into a one-dimensional relativistic electromagnetic particle-in-cell code, testing it against plasma oscillations, two-stream instabilities and strongly magnetized relativistic shocks.

The pulsar phenomenon

1992 ◽  
Vol 341 (1660) ◽  
pp. 3-15 ◽  
Keyword(s):  
Neutron Stars ◽  
Electromagnetic Fields ◽  
Pulse Emission ◽  
Emission Process ◽  
Companion Star ◽  
Single Neutron ◽  
Wide Range ◽  
Binary Orbit ◽  
Almost All ◽  
Insight Into

The discovery 25 years ago of the remarkable objects which came to be known as pulsars, and their identification as neutron stars, fulfilled a prediction made more than 30 years earlier. Over 550 pulsars are now known, almost all detected at radio frequencies. Their pulse periods range from 1.5 ms to several seconds. Most pulsars are single neutron stars but, in an im portant subset, the pulsar is in a binary orbit with a companion star. Observations have revealed a wealth of detail about the structure and evolution of pulsars and the pulse-emission process, giving new insight into the behaviour of m atter in the presence of extrem e gravitational and electromagnetic fields. Pulsars have unique properties which make them nearly ideal probes for a wide range of physical studies. Those observational results which are most relevant to these applications are summarized in this paper.

Particle acceleration and electromagnetic field of deformed neutron stars

2019 ◽  
Vol 35 (09) ◽  
pp. 2050056 ◽  
Author(s):  
Javlon Rayimbaev ◽  
Bobur Turimov ◽  
Figueroa Marcos ◽  
Satimbay Palvanov ◽  
Azamkhan Rakhmatov
Keyword(s):  
Magnetic Field ◽  
Particle Acceleration ◽  
Neutron Star ◽  
Neutron Stars ◽  
Electromagnetic Fields ◽  
Deformation Parameter ◽  
Radio Pulsar ◽  
Slow Rotation ◽  
Polar Cap ◽  
Surface Magnetic Field

Neutron stars (NS)s are astrophysical objects with strong gravitational and electromagnetic fields. Since there are several effects on radiation processes around the star, it is impossible to consider whole effects all together. One way to study the processes is by considering them one by one as a toy model. In this paper, we have investigated the effects of spacetime deformation on the surface magnetic field of the slowly rotating neutron star and its plasma magnetospheric processes, such as the plasma magnetosphere formation around the star. At first, the approximate vacuum solutions of the Maxwell equations for the electromagnetic fields of a magnetized neutron star in a slowly rotating deformed spacetime metric have been obtained. It has been shown that the positive deformation parameter leads to an increase in the value of the (surface) magnetic field at the near zone of the neutron star, while the effect of the negative deformation parameter is vice versa. We have also considered the electric field of the slowly rotating neutron star in the spacetime. In the slow rotation approximation, we have studied the particle acceleration in the polar cap zone, considering the effect of deformation of spacetime on the [Formula: see text]-Lorentz factor of a relativistic charged particle. It is shown that in the case of the positive deformation, an additional gravity occurs around the NS. The effects of spacetime deformation on magneto-dipolar radiation of radio pulsars and polar cap size have also been studied and shown that negative deformation of spacetime increased the radiation luminosity and as positive deformation increases, the luminosity decreases. Size of polar cap region of a neutron star, where magnetic field lines open, increases with increasing the value of the deformation parameter [Formula: see text]. Moreover, we have studied the influence of the spacetime deformation on the death line for radio pulsar, which separates the region in [Formula: see text] [Formula: see text] diagram, where the pulsar can or cannot radiate in radio band (create pair production) through inverse compton scattering (ICS). It is shown that the negative (positive) deformation shifts upward (downward) the death line, which means that even a small negative (positive) deformation of spacetime may cause to be radio-quite (be radio load) the radio pulsar which is lying on the death line (in [Formula: see text] diagram) in the GR frame with its corresponding parameters.

Effect of pulsed electromagnetic fields on maturation of regenerate bone in a rabbit limb lengthening model

2005 ◽  
Vol 24 (1) ◽  
pp. 2-10 ◽  
Author(s):  
Kenneth F. Taylor ◽  
Nozumu Inoue ◽  
Bahman Rafiee ◽  
John E. Tis ◽  
Kathleen A. McHale ◽  
...  
Keyword(s):  
Electromagnetic Fields ◽  
Limb Lengthening ◽  
Pulsed Electromagnetic Fields ◽  
Pulsed Electromagnetic

Effects of 60 Hz Electromagnetic Fields on Melatonin and Sleep in Rats

2001 ◽  
Author(s):  
Jeff Dyche ◽  
Michael Morrissey ◽  
Eric Powell ◽  
A. Michael Anch
Keyword(s):  
Electromagnetic Fields

Developing GIS portal to ensure sanitary and epidemiological surveillance of transferring radio engineering objects

2020 ◽  
Vol 99 (4) ◽  
pp. 344-350
Author(s):  
Evgeny V. Zibarev ◽  
A. S. Afanasev ◽  
O. V. Slusareva ◽  
T. I. Muragimov ◽  
V. A. Stepanets ◽  
...  
Keyword(s):  
Electromagnetic Fields ◽  
Analytical Data ◽  
Base Stations ◽  
Epidemiological Surveillance ◽  
Graphical Form ◽  
Residential Areas ◽  
Information Portal ◽  
Radiofrequency Electromagnetic Fields ◽  
Online Mode ◽  
Automated Processes

In recent years, in the Russian Federation there has been an increase in the levels of radiofrequency electromagnetic fields in residential areas, including due to an increase in the number of base stations (BS). The purpose of sanitary and epidemiological surveillance at the stages of placement and commissioning of base stations (BS) is to prevent their adverse effects on public health. The increase in the number of base stations, together with the advent of new electronic equipment and antennas, provide opportunities for improving the processes of their accounting at the stage of placement and monitoring of the levels of radiofrequency electromagnetic fields at the operation stage. This automation tool can be a geo-information portal for providing sanitary and epidemiological surveillance of cellular base stations. The prototype of the geo-information portal allows both calculating the size of sanitary protection zones (SPZ) and building restriction zones (RZ) from the BS in online mode, displaying the results of calculations in graphical form and issuing sanitary and epidemiological conclusions for the placement and operation of base stations. The geo-information portal has the ability to synchronize with the data of the radio frequency center. Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing will be able to receive up-to-date analytical data. There will be completely automated processes of collecting, processing and storing information on BS.

Sign in / Sign up

Export Citation Format

Share Document