Fundamental physical features of resonant spontaneous bremsstrahlung radiation of ultrarelativistic electrons on nuclei in strong laser fields

Abstract Theoretically predicted fundamental features in the process of resonant spontaneous bremsstrahlung radiation during the scattering of ultrarelativistic electrons with energies of the order ∼ 100 GeV by the nuclei in strong laser fields with intensities up to I ∼ 1024 W cm−2. Under resonant conditions, an intermediate electron in the wave field enters the mass shell. As a result, the initial second-order process by the fine structure constant is effectively reduced to two first-order processes: laser-stimulated Compton effect and laser-assisted Mott process. The resonant kinematics for two reaction channels (A and B) is studied in detail. An analytical resonant differential cross-section with simultaneous registration of the frequency and the outgoing angle of a spontaneous gamma-quantum for channels A and B is obtained. The resonant differential cross section takes the largest value with a small number of absorbed laser photons. In this case, the resonant cross-section is determined by one parameter, depending on the small transmitted momenta, as well as the resonance width. In strong fields, spontaneous gamma quanta of small energies are most likely to be emitted compared to the energy of the initial electrons. At the same time, the angular width of the radiation of such gamma quanta is the largest. With an increase in the number of absorbed laser photons, the resonant cross-section decreases quite quickly, and the resonant frequency of spontaneous gamma quanta increases. It is shown that the resonant differential cross-section has the largest value in the region of average laser fields (I ∼ 1018 W cm−2) and can be of the order of ∼ 1 0 19 in units Z 2 α r e 2 . With an increase in the intensity of the laser wave, the value of the resonant differential cross-section R r e s max decreases and for the intensity I ∼ 1024 W cm−2 is R r e s max ≲ 1 0 7 in units Z 2 α r e 2 . The obtained results reveal new features of spontaneous emission of ultrarelativistic electrons on nuclei in strong laser fields and can be tested at international laser installations.

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Resonant Breit-Wheeler process in an external electromagnetic field

Modern Physics Letters A ◽

10.1142/s0217732320400271 ◽

2020 ◽

Vol 35 (03) ◽

pp. 2040027 ◽

Cited By ~ 1

Author(s):

Alexander A. Pustyntsev ◽

Victor V. Dubov ◽

Sergei P. Roshchupkin

Keyword(s):

Differential Cross Section ◽

External Field ◽

Pair Production ◽

Cross Section ◽

Differential Cross ◽

Single Photon ◽

Gamma Quantum ◽

Structure Constant ◽

Fine Structure Constant ◽

Electron Positron

The contemporary research scrutinizes the resonant Breit-Wheeler process in the field of a plane monochromatic electromagnetic wave. Implementing the weak external field condition the processes of electron-positron pair production advances pre-eminently with participation of restrictively two field photons. Thus, within the resonant state the represented process effectively splits into two first-order processes with respect to the fine-structure constant. In details, the effect indicates the single photon pair production with consequent absorption of gamma quantum by an electron (positron) in the field of the wave. We analyze the resonance kinematics precisely. The study determines specific regions in which the interference of resonant amplitudes is absent. Additionally, the computation obtains a resonant differential cross section for the described areas. The corresponding resonant differential cross section significantly exceeds the correlating Breit-Wheeler cross-section without an external field. Various scientific facilities of pulsed laser radiation may experimentally verify the results of these calculations (SLAC, FAIR, XFEL, ELI, XCELS).

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Resonant production of electron-positron pairs by a hard gamma-ray on a nucleus in an external electromagnetic field

Modern Physics Letters A ◽

10.1142/s0217732320400258 ◽

2020 ◽

Vol 35 (03) ◽

pp. 2040025 ◽

Cited By ~ 2

Author(s):

Nikita R. Larin ◽

Victor V. Dubov ◽

Sergei P. Roshchupkin

Keyword(s):

Electromagnetic Field ◽

Differential Cross Section ◽

External Field ◽

Cross Section ◽

Differential Cross ◽

Gamma Ray ◽

Structure Constant ◽

External Electromagnetic Field ◽

Electron Positron ◽

Resonant Production

The resonant production of electron-positron pairs by a hard gamma-ray on nucleus in an external electromagnetic field is studied theoretically. The main property of this process is that the initial process of the second order in the fine structure constant in an external field effectively splits into two successive processes of the first order due to the fact that in resonant conditions intermediate virtual electron (positron) becomes a real particle. One of these processes is a single-photoproduction of electron-positron pair in a laser field (laser-stimulated Breit-Wheeler process) another is a laser-assisted scattering of electron (positron) on nucleus (laser-assisted Mott scattering). It is shown that the resonances are possible only for the energies of the initial hard gamma-ray more than the characteristic threshold energy. Resonant differential cross section of this process is obtained. It is shown that the resonant differential cross section can significantly exceed the corresponding cross section without an external field. The obtained results may be experimentally verified using the facilities of pulsed laser radiation (SLAC, FAIR, XFEL, ELI, XCELS).

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The Resonant Bremsstrahlung of Ultrarelativistic Electrons on a Nucleus with Radiation of Hard Gamma-Quanta in the Presence of a Pulsed Field of the X-ray Pulsar

Universe ◽

10.3390/universe6090143 ◽

2020 ◽

Vol 6 (9) ◽

pp. 143

Author(s):

Alexander Dubov ◽

Victor V. Dubov ◽

Sergei P. Roshchupkin

Keyword(s):

Electromagnetic Field ◽

Cross Section ◽

Cross Sections ◽

Differential Cross ◽

Gamma Quantum ◽

Structure Constant ◽

High Energy ◽

Fine Structure Constant ◽

Order Effects ◽

X Ray

The investigation scrutinizes the circulation of the large-scaled fluxes of ultrarelativistic electrons near the neutron stars. This work focuses on the effects that occur during the adjustment of the strong electromagnetic field near the X-ray pulsars. Particularly, this study analyzes the resonant high-energy spontaneous bremsstrahlung of ultrarelativistic electrons in the pulsed fields of a nucleus and X-ray pulsar. Specific attention is given to the pulsed character of the field model. Under the resonant conditions the intermediate virtual electron within the electromagnetic field transforms into a real particle. As a result, the initial second-order process with accordance to the fine structure constant effectively splits into two first-order effects: the stimulated Compton process and the field-assisted scattering of an electron on a nucleus. In this research we obtain the resonant differential cross-sections with registration of frequency and radiation angle of a hard gamma-quantum. To summarize, the resonant differential cross-section of the effect within the external pulsed electromagnetic field of X-ray pulsar significantly exceeds the corresponding cross-section without an external field.

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Mott scattering in strong laser fields revisited

Canadian Journal of Physics ◽

10.1139/p08-109 ◽

2009 ◽

Vol 87 (4) ◽

pp. 299-310

Author(s):

B. Manaut ◽

Y. Attaourti ◽

S. Taj ◽

S. Elhandi

Keyword(s):

Differential Cross Section ◽

Field Strength ◽

Electric Field ◽

Electric Field Strength ◽

Cross Section ◽

Differential Cross ◽

Laser Field ◽

Bessel Functions ◽

Strong Laser ◽

Mott Scattering

In this work, we review and correct the first Born differential cross section for the process of Mott scattering of a Dirac–Volkov electron, namely, expression (26) derived by Szymanowski et al. (Phys. Rev. A, 56, 3846 (1997)). In particular, we disagree with the expression of (dσ/dΩ) that they obtained and we give the exact coefficients multiplying the various Bessel functions appearing in the scattering differential cross section. Comparison of our numerical calculations with those of Szymanowski et al. shows qualitative and quantitative differences when the incoming total electron energy and the electric-field strength are increased particularly in the direction of the laser propagation. Such corrections are very important since the relativistic electronic dressing of any Dirac–Volkov charged particle gives rise to these coefficients that multiply the various Bessel functions, and the relativistic study of other processes (such as excitation, ionization, etc….) depends strongly upon the correctness and reliability of the calculations for this process of Mott scattering in the presence of a laser field. Our work has been accepted, Attaourti and Manaut (Phys. Rev. A, 68, 067401 (2003)) but only as a comment. In this paper, we give full details of the calculations as well as a clear explanation of the large discrepancies that their results could cause when working in the ultra relativistic regime and using a very strong laser field corresponding to an electric field strength ε = 5.89 au.

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