In this paper, we study a gas of (N gg 1 ) weakly interacting fermions. We describe the time evolution of states that are perturbations of the Fermi ball, and analyze the dynamics in particle-hole variables. Our main result states that, for small values of the coupling constant and for appropriate initial data, the effective dynamics of the momentum distribution is determined by a discrete collision operator of quantum Boltzmann form.
Comprehending the dynamics of dust acoustic modes and the ability to tune their effective parameters facilitates the optimization of plasma phenomena and structures, while also providing deeper insights into the underlying physics of oscillations involving massive charged grains. In this study, we investigate the influence of cathode potential on the evolution of dust ion acoustic (DIA) waves in a multicomponent dusty plasma containing a separate electron beam (e-beam). Our analysis reveals that cathode potential plays a crucial role in modulating the effect of the e-beam on DIA mode dynamics. Notably, at a specific cathode potential, denoted as (:{varphi:}_{CN}), the contribution of the e-beam to DIA wave propagation becomes negligible. Numerical results indicate that (:{varphi:}_{CN}) gradually increases with rising concentration of negatively charged grains, a trend that becomes more pronounced at elevated electron temperatures. Furthermore, in plasmas containing negatively charged grains, increasing the electron number density induces a nonlinear decrease in (:{varphi:}_{CN}), conversely, in plasmas with positively charged dust grains, the opposite trend is observed. Our findings offer an effective strategy for manipulating e-beam-induced modifications in DIA mode behavior.
We have simulated the recording of one of the brightest gamma-ray bursts, GRB 221009A, with a segmented scintillation detector. Based on the analysis of Konus-WIND observations, we reproduced the spectral characteristics of the burst in our simulation. Particular attention was given to the influence of instrumental (dead time and pile-up) effects on the accuracy of reconstructing the energy spectrum and polarization of the emission at extremely high fluxes. Detector segmentation was shown to reduce significantly the distortion of the recorded spectrum. We found that a reliable polarization measurement is possible at fluxes up to ({sim}10^{-5}) erg cm({}^{-2}) s({}^{-1}), whereas at fluxes ({sim}10^{-2}) erg cm({}^{-2}) s({}^{-1}) (the main peak of the burst light curve) a polarization measurement is impossible due to the significant influence of the dead time and pile-up effects.
An approach employing the transmittance matrix has been implemented to calculate the intensity of Bragg reflections in resonant X-ray diffraction. This enables the inclusion of anisotropic effects that lead to a change in the polarization of radiation during propagation. Using the example of processing the spectra of forbidden reflections in an iron orthoborate crystal, performed with a program based on this approach, an improvement in the agreement between calculated results and experimental data is demonstrated in comparison with standard methods.
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