Showing papers on "Synchrotron radiation published in 1970"

Bremsstrahlung, Synchrotron Radiation, and Compton Scattering of High-Energy Electrons Traversing Dilute Gases

Abstract: Expressions are derived for the total energy loss and photon-production spectrum by the processes of Compton scattering, bremsstrahlung, and synchrotron radiation from highly relativistic electrons. For Compton scattering, the general case, the Thomson limit, and the extreme Klein-Nishina limit are considered. Bremsstrahlung is treated for the cases where the electron is scattered by a pure Coulomb field and by an atom. For the latter case the effects of shielding are discussed extensively. The synchrotron spectrum is derived for an electron moving in a circular orbit perpendicular to the magnetic field and also for the general case where the electron's motion is helical. The total photon-production spectrum is derived for each process when there is a power-law distribution of electron energies. The problems of the effects of the three processes on the electron distribution itself are considered. It is shown that if the electron loses a small fraction of its energy in a single occurrence of a process, the electron distribution function satisfies a continuity equation which is a differential equation in energy space. For the more general case where the electron can lose energy in discrete amounts (as in bremsstrahlung and extreme Klein-Nishina Compton losses), the electron distribution function satisfies an integro-differential equation. Some approximate solutions to this equation are derived for certain special cases.

Soft X-Ray Spectra of the Lithium Halides and Their Interpretation

Abstract: The photoabsorption of LiF, LiCl, and LiBr has been investigated with high resolution at quantum energies from 60 to 230 eV using synchrotron radiation from an electron storage ring. It is found that the spectra can be understood largely in terms of transitions from the various core levels to the final-band density of states as obtained from recent band calculations. Features are found which may possibly be due to replication of the edge with the emission of one or more collective excitations.

Extreme Ultraviolet Spectroscopy with the Use of a Storage Ring Light Source

Abstract: The 240 MeV storage ring at the Physical Science Laboratory of the University of Wisconsin has been used as a source of radiation for extreme uv spectroscopy in the 40–400 A wavelength range The characteristics of the synchrotron radiation emitted by this machine are summarized The experimental setup with a 2 m grazing spectrometer and the data acquisition system is described along with some of the procedures used for thin film photoabsorption measurements

Synchrotron emission at strong radiative damping.

Abstract: Synchrotron emission of relativistic particle in magnetic field with radiative reaction force comparable to Lorentz force, emphasizing pulsar cosmic ray electron acceleration

Synchrotron Radiation as a Standard of Spectral Emission

Abstract: Synchrotron radiation is being investigated as an alternative standard to black-body radiation for establishing standards of spectral emission, particularly in the ultraviolet. Initial measurements, in which the radiation has been compared with existing standards, have shown good agreement between the measured and predicted distributions over the range 350 to 600 nm. It is hoped to use the radiation to calibrate deuterium lamps, initially down to 200 nm, for use as working standards.

Low frequency cosmic noise observations of the constitution of the local system

Abstract: Mathematical models for electron distribution, synchrotron radiation, flux, and spectrum of low energy cosmic ray electrons in interstellar media

A model for the radiations from the compact strong sources

Abstract: Astronomical model for origins and time variations of compact strong sources radiation over all bands

Low-frequency cutoffs in synchrotron spectra.

Abstract: Synchrotron source spectra natural frequency cut- off in absence of self absorption and electron energy cut-offs, discussing pulsar NP 0532

A Synchrotron Model for the Decimetric Rradiation of Jupiter

Abstract: The two-dimensional distribution of intensity and polarization has been calculated for the synchrotron radiation from electrons trapped in a dipolar magnetic field around a planet. From formulas recently published by Legg and Westfold, the circular polarization is included. The integrated data from these maps are used to suggest models with two thick belts of electrons to account for the decimetric radiation from Jupiter.

Neutrino synchrotron radiation. ii. application to neutron stars.

Abstract: The neutrino luminosity of several models of neutron stars has been computed according to the photon-neutrino coupling theory and compared with that of the current-current coupling theory. It is shown that the NSR process alone should have cooled the core of the neutron star created in a supernova explosion in 1954 A.D. to a temperature around 2×109 K according to the photon-neutrino coupling theory.The emission power of the star is greater than the emission power of the X-ray source discovered in the Crab Nebula; so the source may be interpreted as the thermal radiation of the star according to the photon-neutrino coupling theory.

Neutrino synchrotron radiation. i. application to white dwarfs.

Abstract: The neutrino synchrotron radiation for a completely relativistic electron gas in the presence of large magnetic field is computed according to the photon neutrino coupling theory of weak interactions. The radiation is also estimated for the non-relativistic case. The neutrino luminosity of several model white dwarfs are computed according to the photon-neutrino coupling theory and compared with that of the current-current coupling theory. It is shown that, according to the photonneutrino coupling theory, the neutrino luminosity is greater than the photon luminosity and, therefore, most likely to have astrophysical significance in the evolution of stars with large electron energies and potentially large magnetic field, such as white dwarfs.

Low Mode Coherent Synchrotron Radiation and Pulsar Phenomena

Abstract: Information on the properties and distributions of the charges responsible for pulsar emission can be deduced from an appraisal of the coherent synchrotron radiation from an oblique rotator model.

On the isotropization of electrons in synchrotron sources

Abstract: Electrons radiating synchrotron radiation develop a pitch angle anisotropy, and so become unstable to the coherent emission of hydromagnetic waves. The evolution of the coupled system of anisotropic electrons and waves is studied in the absence of any dissipation of the waves in the ambient medium. The anisotropy of the electrons approaches a steady state in which the anisotropy is energy independent and of ordervA/c (vA=Alfven speed). The conditions for this small degree of anisotropy to be maintained are examined.

Inverse Compton process in quasars and Seyfert-type nuclei

Abstract: The inverse Compton spectral power of the infrared source, which is optically thick to its own radiation due to the synchrotron self-absorption process, is calculated. A radio source of a single ensemble of relativistic electrons and magnetic fields is considered. These elec­ trons emit synchrotron radiation, the high frequency part of the high frequency cutoff of which is observed in the infrared frequency range. A small fraction of the synchrotron photons suffers the inverse Compton scattering by the same ensemble of relativistic electrons. The scattered radiation is observed in the optical range. On the basis of this interpretation, the physical parameters of the infrared and optical source of 3C 273 are determined. A pos­ sible role played by the inverse Compton process is discussed for Seyfert-type nuclei. § 1. Introduction and summary In recent years, much attention has been paid to the similarity between some of the quasars and some of the nuclei of Seyfert-type galaxies. A promi­ nent feature of these objects is the enormous energy release in the infrared frequency range. Their output energy so far observed is mainly in this frequency range. Therefore, in orde'r to clarify their structures, it is of prime importance to interpret the large infrared radiation. Though the emission mechanism of the infrared radiation of the quasars and the Seyfert-type nuclei is not yet clear, the synchrotron mechanism is one of likely candidates. The possible presence of polarization in the infrared of 3C 273/) though not confirmed, may support this mechanism. We assume the infrared radiation of quasars and Seyfert-type nuclei to be produced by the synchrotron mechanism. As for the size of infrared emitting region, the rapid time variation with the time scale of the order of one day observed for NGC 1068 and NGC

Vacuum Ultraviolet Plasma Arc Radiation Source for the 300–1000-A Wavelength Region

Abstract: A plasma arc radiation source is described which can produce continuum radiation in the 300–1000-A range from discharges in the gases He, Ne, Ar, Kr, Xe, H2, and their mixtures. The radiation is emitted from a dc self-stabilized plasma arc column having a core temperature of about 18,000 K. The spectra of major interest are due to ion–electron recombination to the ground state of the neutral atom. These continua extend to wavelengths shorter than the first ionization threshold. For helium, the useful continuum extends from 504 A to approximately 350 A. The arc column is observed along its cylindrical axis of symmetry through a small opening in the anode. The radiation source was developed for use in the measurement of cross sections in the vacuum uv using continuously scanning photoelectric spectrometers. The application of the source to measurements in krypton near 500 A is described.

Origin of cosmic rays.

Abstract: The origin of cosmic rays is discussed by paying atteution to the role of possible local sources. From the charge spectrum of primary cosmic rays the charge spectmum at local origins as well as the mean free path for cosmic-ray particles traversing the interstellar matter were deduced. The charge spectrum at sources was discussed in reference to the formation of elements in various stages of the stellar evolution. Various modes of energy transformations in the Crab nebula, as one of the most important local sources, were examined on the basis of the synchrotron radiation and the Californium hypothesis. A detailed analysis of the electromagnetic radiation from the Crab rebula helped to obtain the energy and spatial distributions of relativistic electrons. The balance sheet with regard to the outcome and income of energy was discussed. This indicates a very high efficient of aeceleration possibly due to the motion of magnetic fielda. On that basis, the cause of the high efficiency is that the energy transfer to relativistic particles could be faster than to other modes in such a tenuous plasma. A comparison was made with the acceleration of cosmic rays at the solar flare. A betatron-like process was proposed as amore » possible mechanism of acceleration. In addition to these rather well-known sources, the role of other probable sources was briefly considered with a flew to preparing a thorough review on the origin of cosmic rays. (auth)« less

Synchrotron radiation from mildly relativistic electrons.

Abstract: The exact formula for the intensity of synchrotron radiation emitted by a single charged particle in vacuo was given by Schott, for the case of circular orbits, and Takakura for the case of helical orbits. In the general case the radiated power is expressed in terms of four variables which appear in (among other places) the arguments or orders of a Bessel function and its first derivative; hence the general formula gives little insight into the interpretation of synchrotron radiation and allows evaluation only in particular cases. There is a particular need for approximate formulae that yield the spectrum of the radiation in explicit form. Such approximate formulae were found by Vladimirskii and Schwinger for the case of highly relativistic electrons. In the present paper we outline the derivation of approximate formulae applicable to mildly relativistic electrons, especially those with velocity βc such that 0 ≪ β ≲ O.9. These approximations are also relevant to the case of highly relativistic electrons in a plasma with refractive index appreciably less than unity.

Opaque radio sources near the galactic equator.

Abstract: MANY recent studies1–8 of the continuum spectra of discrete radio sources have provided examples of sources with “opaque” microwave spectra, in which the flux density has a maximum at a frequency greater than 3 GHz. At least two classes of object have such spectra: compact extragalactic sources, frequently identified3,6,9 with quasi-stellar objects or nuclei of galaxies, and galactic HII regions with high electron densities1. The extragalactic objects are thought to be sources of synchrotron radiation within which the relativistic plasma is opaque at microwave frequencies; some exhibit radio variability which can be explained by an expanding optically thick synchrotron source10. The galactic sources are thought to be optically thick emitters of bremsstrahlung radiation; a nonthermal mechanism11 has also been proposed for these objects. The source VRO 42.22.01 (BL Lac) may be an example of a third class characterized by rapid microwave variability. It is uncertain whether this object is a star with a faint diffuse envelope2 or an extragalactic source for which the line of sight is coincidentally close to the galactic plane.

Synchrotron radiation and ring formation in the electron ring accelerator

Abstract: We discuss the possibility of using synchrotron radiation to form electron rings having a very high electric field to hold the ions inside the ring. The formulas describing bow the energy and the dimension of the ring change under the effect of synchrotron radiation are derived, and a numerical example is given.

Effect of plasma inhomogeneity and drifting plasma on synchrotron radiation from magnetoplasma

Abstract: The synchrotron radiation from relativistic charged particles gyrating along a static magnetic field is affected by the background medium. We have shown the effect of uniform magnetoplasma, the plasma inhomogeneity and the drifting plasma on the synchrotron radiation. The radiated synchrotron power for frequencies f/f c ≤ 1 is found to decrease due to the presence of drifting plasma and the synchrotron power in the same frequency range is found to increase due to the presence of plasma in homogeneity. For frequencies f/f c ≥ 1 the plasma inhomogeneity and drifting plasma show negligible effect.

Coherent synchrotron emission in the crab nebula.

Abstract: Coherent synchrotron emission in Crab Nebula associated with electron gyromotion, discussing models for high energy particle acceleration

The Electromagnetic Spectrum of the Crab Nebula

Abstract: The electromagnetic spectrum of the Crab Nebula has been determined experimentally in the radio, optical, and X-ray regions [1], in which it follows a power law of the type S(v)=Av − α ,where S(v)is the power (in watts/m2 sec Hz), A and α are constants, and v is the frequency in Hz. Recent measurements [2–5], however, show a deviation from a power law in the microwave region (see Figure 1). In this paper, we investigate the origin of this deviation and calculate the γ-ray spectrum due to this increase in the microwave photons via the Compton scattering from high-energy electrons.

Absolute Intensity Calibration Methods in the Vacuum UV Region

Abstract: As a summary of the principal results presented at the ESRO symposium on Calibration Methods in the Vacuum Ultra Violet (Munich, 1968) a description is given of three different absolute intensity calibration methods. These are the branching ratio method, the synchrotron radiation method and the black-body radiation method, and they define the present state of the art.