Resonant high-energy bremsstrahlung of ultrarelativistic electrons in the field of a nucleus and a weak electromagnetic wave

Abstract

The actual theoretical research investigates the resonant spontaneous bremsstrahlung (RSB) of ultrarelativistic electrons under the condition of scattering on a nucleus in the field of a weak electromagnetic wave. The progression of the functional mechanism indicates the transformation of the intermediate virtual electron into the real particle state. As a result, the initial second order process with accordance to the fine structure constant in the light field productively splits into two consequent first order formations: the laser-stimulated Compton effect and the laser-assisted scattering of an electron on a nucleus. Precise examination specifies the resonant kinematics of the RSB system that designate the phenomenon of the initial and final electrons with addendum of spontaneous high-energy photon propagation in the narrow angle cone. Furthermore, it is important to emphasize that the resonance escalation possesses a possibility to develop within two reaction channels. Thus, the first channel delineates the occurrence that correlates to the spontaneous photon emission by an electron (laser-stimulated Compton interaction) with subsequent scattering on a nucleus (laser-assisted Mott procedure). The second channel illustrates the configuration corresponding to the electron scattering on a nucleus with consecutive spontaneous photon emission in the wave field. Therefore, with implementation of the equivalent elementary criteria the value of the resonant frequency for the first channel perpetually represents a deteriorative counterpart to the second alternative. Moreover, the spontaneous photon radiation angle allocates a single-valued dependency with the resonant frequency for the first channel in contrast to the second displacement that categorizes a composite area with three various resonant frequency magnitudes for the particular emission angle diapason. The project data analysis proposes that the reaction channels do not interfere within the whole range of observation with a specific evaluation for the particles propagation at zero scattering angle. As a result of the investigation the calculations determine the scattering differential cross-section of the resonant construct development. To summarize, the particular cross-section within the resonant ambience significantly exceeds the according cross-section in the approximation of an external field absence. In conclusion, numerous scientific facilities with specialization in pulsed laser radiation (SLAC, FAIR, XFEL, ELI, XCELS) may experimentally validate the computational estimations.

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

“…The resonant behavior of the amplitude (4) and ( 5) is due to the quasi-discrete structure of the system: an electron + a plane electromagnetic wave, as a result of which the four-quasimomentum of the intermediate electron, due to the implementation of the laws of conservation of energy-momentum in the components of the process, lies on the mass shell [27][28][29]34]. Because of this, for channels A and B, we get:…”

“…The wave functions of the electron are determined by the Volkov functions [50], the intermediate states of the electron are given by the Green function in the field of a plane light wave (2) [51,52]. The amplitude of such a process after simple calculations can be represented in the following form (see, for example, [27][28][29]):…”

Resonant Production of an Ultrarelativistic Electron–Positron Pair at the Gamma Quantum Scattering by a Field of the X-ray Pulsar

“…It is important to emphasize that higher-order QED processes with respect to the fine-structure constant in the electromagnetic field (QED processes modified by the electromagnetic field) can occur in a resonant channel. In the electromagnetic field, so-called Oleinik resonances may occur [1,2], as lower-order processes are possible in the external field by the fine-structure constant (QED processes stimulated by the external field) [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]28,29]. It is important to note that the probability of resonant QED processes, occurring in an external field may significantly (by several orders of magnitude) exceed the corresponding probability of such processes without an external field.…”

The Resonant Effect of an Annihilation Channel in the Interaction of the Ultrarelativistic Electron and Positron in the Field of an X-ray Pulsar

“…Another important characteristics of Oleinik resonances is that the probability of the resonant processes in the external field can greatly surpass the probability of the process without an external field. The study of these processes is among the highest priorities and the most intensively developing directions [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] due to the development of high-power laser radiation sources [24][25][26]. Previous works [12][13][14]17,[19][20][21][22] included a study of only the scattering channel of the Oleinik resonance for the interactions of an electron with another electron and the electron with a positron in the field of the electromagnetic wave.…”