摘要:

A method for computing the self-energy correction for highly-ionized and high-Z many electron atoms is proposed and developed. The method is based on a partical wave analysis, and is immediately applicable to general potentials and many-electron wavefunctions.

ISSN:1042-0150    

DOI:10.1080/10420159108220506

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Quantum Electrodynamics (QED) has been extremely successful inits predictive capability for atomic phenomena. Thus the greatest hope for any alternative view is solely to mimic the predictive capability of quantum mechanics (QM), and perhaps its usefulness will lie in gaining a better understanding of microscopic phenomena. Many “paradoxes” and problematic situations emerge in QED. To combat the QED problems, the field of Stochastics Electrodynamics (SE) emerged, wherein a random “zero point radiation” is assumed to fill all of space in an attmept to explain quantum phenomena, without some of the paradoxical concerns. SE, however, has greater failings. One is that the electromagnetic field energy must be infinit eto work. We have examined a deterministic side branch of SE, “self field” electrodynamics, which may overcome the probelms of SE. Self field electrodynamics (SFE) utilizes the chaotic nature of electromagnetic emissions, as charges lose energy near atomic dimensions, to try to understand and mimic quantum phenomena. These fields and charges can “interact with themselves” in a non-linear fashion, and may thereby explain many quantum phenomena from a semi-classical viewpoint. Referred to as self fields, they have gone by other names in the literature: “evanesccent radiation”, “virtual photons”, and “vacuum fluctuations”. Using self fields, we discuss the uncertainty principles, the Casimir effects, and the black-body radiation spectrum, diffraction and interference effects, Schrodinger's equation, Planck's constant, and the nature of the electron and how they might be understood in the present framework. No new theory could ever replace QED. The self field view (if correct) would, at best, only serve to provide some understanding of the processes by which strange quantum phenomena occur at the atomic level. We discuss possible areas where experiments might be employed to test SFE, and areas where future work may lie.

ISSN:1042-0150    

DOI:10.1080/10420159108220507

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

When a relativistic charged particle passes through a single crystal very nearly along a major crystalline plane or axis so that it is channeled in that direction, it undergoes periodic motion in the plane transverse to this direction and hence it can radiate. Quantum mechanically, this channeling radiation corresponds to a radiative transition between two eigenstates of the transverse crystalline potential; when the transition occurs between two bound states, a sharp spectral line is emitted. When there are only two bound states (for incident electrons), or when the interplaner potential is nearly harmonic (as for incident positrons), the emitted radiation is nearly monochromatic. Since the discovery of channeling radiation at the LLNL Electron-Positron Linear Accelerator, many of its properties have been delineated, both there and elsewhere. For example, channeling radiation is very intense, forward-directed, easily tunable, and for the planar case, linearly polarized. Channeling radiation has been used as a probe both of the interplanar potentials and other properties of perfect crystals and of the effects of impurities and defects in imperfect crystals. Finally, channeling radiation has great potential use as a photon source for numerous other applications in several fields of science and technology.

ISSN:1042-0150    

DOI:10.1080/10420159108220508

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The present paper is a review of basic works dedicated to the radiation emitted by channeled particles in crystals in a low (∼100 MeV), intermediate (0.1 ≲E≲ 30 GeV), and high (E≳ 100 GeV) energy ranges.

ISSN:1042-0150    

DOI:10.1080/10420159108220509

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The degree of polarization of channeling radiation emitted by axially channeled electrons has been calculated using the many-beam method. The polarization was found to be substantial, and to increase monotonically with the channeling angle. The many-beam results are compared with those obtained from the single-string approximation and are found to be significantly different.

ISSN:1042-0150    

DOI:10.1080/10420159108220510

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Many authors have studied channeling radiation theoretically by means of the so called many beam approach. For axial channeling this approach tends to involve rather large eigenvalue problems if high accuracy is desired. With the extension to three-dimensional problems in mind we have therefore investigated the possibilities for a more efficient solution of these eigenvalue problems. The Lanczos algorithm [2] used in the preparation of Fig. 1 provides a substantial reduction of the numerical effort. We have also obtained some preliminary results for three-dimensional corrections to the tranverse problem. These corrections were found to be three-dimensional rather than longitudinal in character and tend to reduce the photon energy. The corrections are smaller than 1 percent for 4 MeV electrons in silicon. A more thorough investigation of these effects for the low energy part of the spectrum and a study of their impact on the high energy radiation [3] is now in progress. The conventional transverse many beam approach based on the Lindhard continuum approximation does not describe the latter effect.

ISSN:1042-0150    

DOI:10.1080/10420159108220511

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Based on the method of equivalent photons, incoherent bremsstrahlung probability is obtained as a function of impact parameter. It is shown that incoherent bremsstrahlung is caused by the fluctuation of atomic potential due to thermal vibrations. Numerical value of our result is considerably smaller than those of other theories.

ISSN:1042-0150    

DOI:10.1080/10420159108220512

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The line width problem in channeling radiation is considered in terms of the optical potential method. It is shown that the plasmon excitations do not contribute to the line width.

ISSN:1042-0150    

DOI:10.1080/10420159108220513

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

ISSN:1042-0150    

DOI:10.1080/10420159108220495

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor