Showing papers on "Synchrotron radiation published in 1969"
TL;DR: Particle motions, reabsorption mechanism, and related problems of synchrotron radiation theory are discussed in detail in as discussed by the authors, where the authors present an overview of the problems of as discussed by the authors.
Abstract: Particle motions, reabsorption mechanism, and related problems of synchrotron radiation theory
222 citations
TL;DR: With the synchrotron radiation of DESY, secondary standard light sources have been calibrated in the spectral range 1500-2700 A and the accuracy of the intensity of the calibrated lamp is about 4%.
Abstract: With the synchrotron radiation of DESY (Deutsches Elektronen Synchrotron) as a primary standard light source, secondary standard light sources have been calibrated in the spectral range 1500–2700 A. By this method, the accuracy of the intensity of the calibrated lamp is about 4%.
57 citations
TL;DR: In this article, a continuous record of the 80 MHz image and polarization of a type IV solar outburst has been made with the Culgoora radioheliograph from which the magnetic structure of the event can be directly inferred.
Abstract: A continuous record of the 80 MHz image and polarization of a type IV solar outburst has been made with the Culgoora radioheliograph from which the magnetic structure of the event can be directly inferred. The first (‘moving’) part of the event appears beyond the limb as an expanding magnetic arch along which three concentrated sources develop: one unpolarized source near the peak, attributed to synchrotron radiation; and two polarized sources of opposite polarity near the feet, attributed to plasma radiation. The radio-emitting arch appears to lie above an eruptive prominence seen in Hα. The second (‘stationary’) part is seen later as a separate highly polarized source on the disk above the projected position of the flare that had previously triggered the prominence activity.
50 citations
TL;DR: The absolute absorption coefficient of Ta, W, Re and Pt has been determined in the photon energy range 30-600eV by use of synchrotron radiation at the 7.5-GeV electron synchoretron DESY as discussed by the authors.
46 citations
31 citations
TL;DR: Crab Nebula pulsar NP 0532 photoelectric spectrophotometry results, noting main pulse and interpulse spectral energy distributions similarity to extended synchrotron radiation as discussed by the authors.
Abstract: Crab Nebula pulsar NP 0532 photoelectric spectrophotometry results, noting main pulse and interpulse spectral energy distributions similarity to extended synchrotron radiation
28 citations
TL;DR: Secular variations in small quasar components, discussing compatibility with theory of expanding synchrotron sources as mentioned in this paper, discuss compatibility with the theory of growing synchroron sources.
Abstract: Secular variations in small quasar components, discussing compatibility with theory of expanding synchrotron sources
22 citations
Abstract: THE observation that the pulsar CP 0328 radiates single pulses which seem to be basic elements of the total radio radiation, and which are highly polarized1, led at first to the suggestion that the mechanism of radiation was that of synchrotron radiation, forming a beam of radiation which swept across the observer as the source rotated. The shape of the elementary pulse, and the pattern of polarization across the pulse, were seen to be very similar to the angular distribution of radiation from a highly collimated beam of electrons, and it was suggested that the ratio of the pulse duration of the period of the pulsar provided a measure of the beam width of the radiation, and hence a measure of the energy of the electrons. On this hypothesis the width and polarization of the pulse would be expected to change with radio frequency. We have now looked for any such change in the elementary pulses from CP 0328, and we find none.
21 citations
TL;DR: In this article, the X-ray absorption spectrum of CH 4 was measured by means of the synchrotron radiation and a marked fine structure of the C-K absorption edge was observed.
20 citations
TL;DR: In this paper, an ultrahigh vacuum reflectometer is described, which can be used to study reflectance, transmittance, and photoemission on samples evaporated in situ.
Abstract: An ultrahigh vacuum reflectometer is described. It can be used to study reflectance, transmittance, and photoemission on samples evaporated in situ. The angle of incidence can be varied from 0 to ±90° in steps of 7.5°. The system rotates about the axis of the incident light for study of polarization effects. With the polarized continuum of synchrotron radiation and a normal‐incidence monochromator the reflectometer allows measurements with polarized light at wavelengths down to about 300 A.
TL;DR: Condensed supernova remnants in Crab Nebula, considering various hypotheses for radio source as mentioned in this paper, were found in the Crab Nebula in the early 1990s. But no radio source was identified.
Abstract: Condensed supernova remnants in Crab Nebula, considering various hypotheses for radio source
TL;DR: A 240 MeV electron storage ring has been in operation at the Physical Sciences Laboratory of the University of Wisconsin for one year as mentioned in this paper, where the beam from the synchrotron is injected into the storage ring in a single turn.
Abstract: A 240 MeV electron storage ring has been in operation at the Physical Sciences Laboratory of the University of Wisconsin for one year. The storage ring injector is a 50 MeV FFAG electron synchrotron. The bunched beam from the synchrotron is injected into the storage ring in a single turn. Radio-frequency capture is accomplished by using the signal from the bunched beam as the master oscillator during capture. Using this method, high capture efficiency is achieved. A useful consequence of the method of radio-frequency capture is the damping of the coherent synchrotron oscillation instability. The beam may be accelerated, or decelerated, to any energy within the capability of the ring - 10 MeV to 240 MeV. The vacuum system operates at a pressure in the mid 10-10 range allowing lifetimes of many hours for low intensity beams. During the first year of operation several interesting effects have been observed. Among these were photo etching of metal from the vacuum chamber by synchrotron radiation and enhanced beam loss due to scattering from ions trapped in the electron beam. The beam also exhibits a transverse coherent instability that violates the Courant-Sessler criteria for stability.
TL;DR: In this article, the gamma radiation resulting from various processes associated with high-energy electrons is calculated and it is shown that the magnetic field H near the light-emitting region of the pulsar NP 0532 is 102 ≲ H ≲ 104 G.
Abstract: THE pulsar NP 0532, located in the Crab Nebula, emits pulses of light1,2 with the same period as the radio emission. The polarization2 of the light suggests an origin in the synchrotron radiation process, indicating the presence of high-energy electrons. In this article the gamma radiation resulting from various processes associated with these electrons is calculated. While gamma radiation from NP 0532 has not been observed experimentally, there are observations of gamma radiation from the Crab Nebula3–8 that give upper limits on gamma emission from NP 0532. My calculations and these upper limits lead to the conclusion that the magnetic field H near the light-emitting region of NP 0532 is 102 ≲ H ≲ 104 G.
TL;DR: In this article, an acceleration mechanism which involves compressional motions, the gyrorelaxation effect and the removal of pitch angle anisotropies by the generation of hydromagnetic waves is formulated and applied to a model of the Crab Nebula with acceleration confined to a central region.
Abstract: Ultrarelativistic electrons must be being accelerated in the Crab Nebula to maintain the synchrotron spectrum. Sufficient power to maintain the synchrotron spectrum is supplied by an observed damping of compressional motions in the central region of the nebula (the ‘wisps’ of Baade). An acceleration mechanism which involves compressional motions, the gyrorelaxation effect and the removal of pitch angle anisotropies by the generation of hydromagnetic waves is formulated and applied to a model of the Crab Nebula with acceleration confined to a central region. This can account for the power supplied to the electrons, the overall shape of the spectrum and allows acceleration up to energies corresponding to the synchrotron emission of hard X-rays. The acceleration process tends to flatten an initial energy spectrum.
TL;DR: In this article, it was shown that synchrotron radiation can be amplified when a monoenergetic electron stream is gyrating in a helical path in the static magnetic field of a cold magnetoactive plasma.
Abstract: Employing the Einstein-coefficients approach, it is shown that synchrotron radiation can be amplified when a monoenergetic electron stream is gyrating in a helical path in the static magnetic field of a cold magnetoactive plasma. Errors appearing in recent literature concerning synchrotron radiation are pointed out. The frequency dependence of the amplification rate is discussed with the aid of some numerical examples. In the limiting case when the helical stream becomes a strictly rotating bunch, the result obtained is identical with that derived from the classical kinetic treatment.
TL;DR: In this article, a relativistic phase trapping of the energetic electrons by an electromagnetic wave propagating perpendicular to the magnetic field is proposed. But the model is not suitable for the case where the background plasma is sufficiently dense.
Abstract: Electromagnetic radiation generated by electrons with several hundred keV of energy gyrating in a dense magnetized plasma has been studied both experimentally and theoretically. Radiation with an intensity several thousand times greater than that generated by the single particle synchrotron process is observed at the second cyclotron harmonic if the background plasma is sufficiently dense. A critical condition for the generation of this radiation is that the upper hybrid resonance frequency of the background plasma be greater than the observation frequency. The observations are related to a relativistic phase trapping of the energetic electrons by an electromagnetic wave propagating perpendicular to the magnetic field. The plasma instability mechanism proposed is in good agreement with the observations.
TL;DR: In this article, a method for discriminating between synchrotron radiation and the cosmic background on the basis of polarization is presented. But the method is not suitable for high altitude Earth satellite observations, since the observed brightness will appear a great deal brighter than average.
Journal Article•
TL;DR: Anisotropic anisotropy of relativistic cosmic ray electrons, considering electron exposure time to synchrotron effects, energy loss from inverse Compton effect, etc.
Abstract: Anisotropy of relativistic cosmic ray electrons, considering electron exposure time to synchrotron effects, energy loss from inverse Compton effect, etc
TL;DR: In this article, the incoherent synchrotron radiation power emitted by relativistic electrons gyrating in a cold magnetoactive plasma is derived, correcting errors which have occurred in the past literature.
Abstract: In this paper, the incoherent synchrotron radiation power emitted by relativistic electrons gyrating in a cold magnetoactive plasma is rederived, correcting errors which have occurred in the past literature. One can specify the background plasma by the quantity A = ωp2/ωH2 (ωp is the angular electron plasma frequency and ωH is the angular electron gyro-frequency), i.e. the relative importance of the plasma frequency to the gyro-frequency. The general spectral features of synchrotron radiation from single electrons radiating in plasmas of large and small are discussed with the aid of a number of numerical examples.
TL;DR: In this paper, a model of the magnetospheric environment based on satellite and ground-based measurements was applied to estimate satellite-observed synchrotron emission from trapped electrons in the inner trapped radiation belt.
Abstract: Estimates of satellite-observed synchrotron emission are made by applying the appropriate theory to a model of the magnetospheric environment based on satellite and ground-based measurements. Emission from electrons in the inner trapped radiation belt is most intense for ray paths that lie close to the geomagnetic equatorial plane. For a satellite observer at a geocentric distance of 4 RE the peak synchrotron brightness is about 1.5 × 10−20 w/m² Hz ster for frequencies of 3 to 10 MHz, decreasing sharply for frequencies below 1 MHz and falling gradually for frequencies greater than 10 MHz. This peak emission is about a factor of 5 below the cosmic noise from the brightest portion of the sky but a factor of more than 100 above the dimmest portion. Since synchrotron emission is strongly polarized at the source and the cosmic background is not, the detection of synchrotron emission against a stronger but randomly polarized background by means of polarization discrimination techniques is investigated and found to be useful. It is concluded that synchrotron radiation from trapped electrons is strong enough to be observed by a satellite receiver thus providing information regarding geomagnetically trapped electrons. This synchrotron radiation could also be a cause of confusion during satellite radio astronomical measurements in the 1- to 15-MHz frequency range.
TL;DR: Synchrotron radiation rate from deexcitation of electrons in magnetic orbits of low quantum numbers, stressing electrons radiation in intense magnetic fields is studied in this article, where it is shown that electrons deexcite in magnetic fields.
Abstract: Synchrotron radiation rate from deexcitation of electrons in magnetic orbits of low quantum numbers, stressing electrons radiation in intense magnetic fields
TL;DR: Gyrosynchrotron from accelerated electron, discussing effects of cold and collisionless magnetoplasma on far field and frequency spectra as discussed by the authors, discussed the effects of magnetoplasmas on the Far Field and Frequency Spectra
Abstract: Gyrosynchrotron from accelerated electron, discussing effects of cold and collisionless magnetoplasma on far field and frequency spectra
TL;DR: In this paper, the familiar equations for the synchrotron radiation of an electron moving in a constant and uniform magnetic field are refined and corrected for the case of a helical trajectory.
Abstract: The familiar equations for the synchrotron radiation of an electron moving in a constant and uniform magnetic field are refined and corrected for the case of a helical trajectory. Particular attention is paid to account of the subsequent approximations in the asymptotic equation. This permits a significant expansion of the range of applicability of the approximate methods for studying the synchrotron radiation when there is a longitudinal velocity component.
TL;DR: In this paper, the synchrotron oscillation for a ring structure subdivided into discrete with acceleration and synchoretron radiation, respectively, is investigated for very high energies, and a more correct value for the synchnrotron frequency and the bunch dimensions and also a limit for the stability of the linearized synchnropton oscillation are obtained.