scholarly journals Resolution of the PSR 1919+21 Magnetosphere Emitting Region

1992 ◽  
Vol 128 ◽  
pp. 287-289
Author(s):  
O. A. Kuz'min
Keyword(s):  
Radio Emission ◽  
Regular Structure ◽  
Phase Changes ◽  
Scintillation Spectrum ◽  
Radio Scintillation ◽  
Light Cylinder ◽  
Average Profile

AbstractRegular structure with 10 to 50kHz-scale was detected in the radio scintillation spectrum of PSR 1919+21. This regular structure may be a simple interferometric pattern formed by refractive multi-ray propagation between the pulsar and observer. It was found that the pulsar PSR 1919+21 radio emission scintillation spectrum phase changes significantly across the average profile. Within the refractive scattering scenario this phase-longitude dependence corresponds to a transversal shift of the magnetosphere emitting region of about 6 x 108 cm. The radio emission altitude is estimated to be near the light cylinder.

scholarly journals Single-Pulse Intensity Fluctuations by Cross-Correlation with Longitude of the Average Profile

1992 ◽  
Vol 128 ◽  
pp. 271-277
Author(s):  
M.V. POPOV ◽  
W. Sieber
Keyword(s):  
Spectral Analysis ◽  
Radio Emission ◽  
Cross Correlation ◽  
Regular Structure ◽  
Single Pulse ◽  
Pulse Intensity ◽  
Pulse Radio ◽  
Average Profile ◽  
Intensity Fluctuations

Single-pulse radio emission from pulsars has been observed to vary both in intensity and position inside the pulse window. In some cases the variations show a rather regular structure (drifting subpulses). Such a regular structure can clearly be studied by fluctuation spectral analysis. The analysis has identified some particular peculiarities in the fluctuation spectra at different longitudes of the pulse window in many pulsars (Backer 1973, Page 1973, Popov and Smirnova 1982). In pulsars with complex integrated profiles (PSR 1919+21, PSR 1237+25) narrow features in the fluctuation spectra vary strongly with longitude, at some longitudes being quite undistinguishable.

scholarly journals Whence the pulses?

1996 ◽  
Vol 160 ◽  
pp. 139-146 ◽  
Author(s):  
D.B. Melrose
Keyword(s):  
Radio Emission ◽  
Pair Production ◽  
Emission Mechanism ◽  
Maser Emission ◽  
Light Cylinder

AbstractRadio emission mechanisms for pulsars are reviewed with emphasis on five possible sites for the emission: the pair production front (PPF), two regions in the relativistically outflowing plasma (denoted ROP1 and ROP2) between the PPF and the light cylinder (LC), and two sited near the LC. Several maser emission mechanism are viable for ROP1, where radius-to-frequency mapping applies. Suggested Schott radiation from outside the LC is discussed critically.

scholarly journals On the beam properties of radio pulsars with interpulse emission

2019 ◽  
Vol 490 (4) ◽  
pp. 4565-4574 ◽  
Author(s):  
Simon Johnston ◽  
Michael Kramer
Keyword(s):  
Radio Emission ◽  
Circular Polarization ◽  
Visible Emission ◽  
Radio Pulsars ◽  
Polarization Data ◽  
Substantial Evidence ◽  
High Quality ◽  
Emission Beam ◽  
Average Profile ◽  
Better Than

ABSTRACT In the canonical picture of pulsars, radio emission arises from a narrow cone centred on the star’s magnetic axis but many basic details remain unclear. We use high-quality polarization data taken with the Parkes radio telescope to constrain the geometry and emission heights of pulsars showing interpulse emission, and include the possibility that emission heights in the main and interpulse may be different. We show that emission heights are low in the centre of the beam, typically less than 3 per cent of the light cylinder radius. The emission beams are underfilled in longitude, with an average profile width only 60 per cent of the maximal beamwidth and there is a strong preference for the visible emission to be located on the trailing part of the beam. We show substantial evidence that the emission heights are larger at the beam edges than in the beam centre. There is some indication that a fan-like emission beam explains the data better than conal structures. Finally, there is a strong correlation between handedness of circular polarization in the main and interpulse profiles, which implies that the hand of circular polarization is determined by the hemisphere of the visible emission.

scholarly journals Origin of Giant Radio Pulses

2004 ◽  
Vol 218 ◽  
pp. 369-372 ◽  
Author(s):  
Ya. N. Istomin
Keyword(s):  
Magnetic Field ◽  
Radio Emission ◽  
Magnetic Reconnection ◽  
Electric Discharge ◽  
Alfvén Waves ◽  
Light Cylinder ◽  
Zero Line ◽  
Field Lines ◽  
Magnetic Poles ◽  
The Magnetic Field

A model for the origin of giant radio pulses is suggested. Radio emission is generated by the electric discharge taking place due to the magnetic reconnection of field lines connecting the opposite magnetic poles. The reconnection occurs in the region of the light cylinder near the zero line of the magnetic field. The coherent mechanism of radiation is pure maser amplification of Alfvén waves. The radiated frequencies are found.

scholarly journals The Location, Spectrum and Beamwidth of Pulsar Radiation from Polar Cap Models

1981 ◽  
Vol 95 ◽  
pp. 107-109
Author(s):  
B. J. Rickett ◽  
J. M. Cordes
Keyword(s):  
Neutron Star ◽  
Radio Emission ◽  
Radio Pulse ◽  
Temporal Variations ◽  
Narrow Beam ◽  
Polar Cap ◽  
Pulse Profile ◽  
Beam Shape ◽  
Pulsar Radiation ◽  
Average Profile

In the rotating “lighthouse” interpretation of pulsars, the average radio pulse profile is generally assumed to be a section through the average beam shape radiated by a spinning neutron star. The radio emission received in any one particular period usually differs markedly from the average profile. Such variations have been classified as subpulses (~ 3 ms) and micropulses (~ .3 ms); see Cordes (1979) for examples. However, there is not general agreement as to whether these variations are caused by the rotation of a steady narrow beam or by temporal variations of a wider beam. We first discuss these questions independently of the emitting particle location, and then apply them to a particular model.

The Interpretation of Crystal Lattice Images

1972 ◽  
Vol 30 ◽  
pp. 550-551
Author(s):  
J. M. Cowley ◽  
Sumio Iijima
Keyword(s):  
Crystal Orientation ◽  
Diffraction Theory ◽  
Phase Changes ◽  
Electron Wave ◽  
Crystal Lattices ◽  
Heavy Atoms ◽  
Lattice Images ◽  
The Right ◽  
Intuitive Interpretation ◽  
Suitable Approximation

The imaging of detailed structures of crystal lattices with 3 to 4Å resolution, given the correct conditions of microscope defocus and crystal orientation and thickness, has been used by Iijima (this conference) for the study of new types of crystal structures and the defects in known structures associated with fluctuations of stoichiometry. The image intensities may be computed using n-beam dynamical diffraction theory involving several hundred beams (Fejes, this conference). However it is still important to have a suitable approximation to provide an immediate rough estimate of contrast and an evaluation of the intuitive interpretation in terms of an amplitude object.For crystals 100 to 150Å thick containing moderately heavy atoms the phase changes of the electron wave vary by about 10 radians suggesting that the “optimum defocus” theory of amplitude contrast for thin phase objects due to Scherzer and others can not apply, although it does predict the right defocus for optimum imaging.

Interrelationship of the cellular distribution and secretion of regular structure (RS) protein in Bacillus licheniformis nm 105

1992 ◽  
Vol 50 (1) ◽  
pp. 712-713
Author(s):  
Xiaorong Zhu ◽  
Richard McVeigh ◽  
Bijan K. Ghosh
Keyword(s):  
Alkaline Phosphatase ◽  
Bacillus Licheniformis ◽  
Self Assembly ◽  
Gel Electrophoresis ◽  
Culture Supernatant ◽  
Regular Structure ◽  
The Self ◽  
Cellular Distribution ◽  
Structural Protein ◽  
Laboratory Cultures

A mutant of Bacillus licheniformis 749/C, NM 105 exhibits some notable properties, e.g., arrest of alkaline phosphatase secretion and overexpression and hypersecretion of RS protein. Although RS is known to be widely distributed in many microbes, it is rarely found, with a few exceptions, in laboratory cultures of microorganisms. RS protein is a structural protein and has the unusual properties to form aggregate. This characteristic may have been responsible for the self assembly of RS into regular tetragonal structures. Another uncommon characteristic of RS is that enhanced synthesis and secretion which occurs when the cells cease to grow. Assembled RS protein with a tetragonal structure is not seen inside cells at any stage of cell growth including cells in the stationary phase of growth. Gel electrophoresis of the culture supernatant shows a very large amount of RS protein in the stationary culture of the B. licheniformis. It seems, Therefore, that the RS protein is cotranslationally secreted and self assembled on the envelope surface.

Remote diagnostics of vibrations of dynamic objects by Doppler microwave sensors

Metrologiya ◽  
2020 ◽  
pp. 25-42
Author(s):  
Dmitrii V. Khablov
Keyword(s):  
Intelligent Systems ◽  
Electromagnetic Waves ◽  
Continuous Monitoring ◽  
Phase Changes ◽  
Vibration Diagnostics ◽  
Remote Diagnostics ◽  
Active Vibration ◽  
Dynamic Objects ◽  
Microwave Sensors ◽  
Non Destructive

This paper describes a promising method for non-contact vibration diagnostics based on the use of Doppler microwave sensors. In this case, active irradiation of the object with electromagnetic waves and the allocation of phase changes using two-channel quadrature processing of the received reflected signal are used. The modes of further fine analysis of the resulting signal using spectral or wavelet transformations depending on the nature of the active vibration are considered. The advantages of this non-contact and remote vibration analysis method for the study of complex dynamic objects are described. The convenience of the method for machine learning and use in intelligent systems of non-destructive continuous monitoring of the state of these objects by vibration is noted.

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