The European Physical Journal D最新文献

Nonlinear propagation of dust ion-acoustic (DIA) solitary waves in a multicomponent dusty plasma composed of negative mobile dusts, non-thermal ions and Boltzmann electrons has been investigated theoretically by incorporating quartic nonlinearity into the system which is very rare in its type. To get detailed behavior of DIA solitary waves, modified Korteweg-de Vries (mKdV) equation is derived with cubic and quartic nonlinearity using usual reductive perturbation technique (RPT). In this new investigation, DIA solitary waves are investigated rigorously and many interesting results are observed on both amplitudes and widths of the solitary waves for different plasma parameters. We observe that, amplitudes and widths of the mKdV dust ion-acoustic (mKdV-DIA) solitons and new mKdV-DIA solitons with quartic nonlinearity (QmKdV-DIA) are greatly affected by the number of dust charge ((Z_d)), dust-to-ion density ratio ((sigma )), initial streaming speeds of ions ((u_{i0})) and dusts ((u_{d0})).

A rigorous theoretical study on the formation and propagation properties of nucleus-acoustic solitary waves has been carried out via the fluid dynamical approach. A three-component thermally degenerate relativistic quantum plasma (TDRQP) system is considered, composed of thermally degenerate relativistic non-inertial electrons and non-inertial non-relativistic degenerate light nuclei (the combined degenerate and thermal pressure of electrons and light nuclei provide the restoring force) and inertial non-degenerate heavy nucleus species (whose mass density provides the inertia). The nonlinear properties of heavy-nucleus-acoustic solitary waves (HNASWs) in such a thermally degenerate quantum plasma are analyzed in detail, via the solitary wave solution of KdV equation. The fundamental characteristics of small-amplitude thermal and degenerate pressure-driven HNASWs in different thermally degenerate plasma medium are analyzed, and the effect of non-relativistically light nucleus and non/ultra-relativistically electron degeneracies, the heavy nucleus temperature effect, the influence of light and heavy nuclei number densities and masses on the propagation dynamics of HNASWs are also examined. It is investigated that the presence of mobile heavy nuclei forms a new waves “heavy-nucleus-acoustic waves (HNAWs)” in TDRQP. It is found that the phase velocity increases with the density of heavy nuclei species, while the increase in mass of heavy nuclei species may lead to the propagation of taller and steeper solitons in TDRQP. It is predicted that the amplitude and the width of the solitary waves increases for ultra-relativistic case. It is also examined that the amplitude and width of HNASWs increases with the decrease in heavy nuclei temperature, while the amplitude (width) increases (decreases) with the increase (decrease) in heavy (light) nuclei number density. The implications of our results for nonlinear structures in astrophysical, space, and laboratory plasma environments are briefly discussed.

G. Hazak and J. Kurzweil discovered a method of configurational resolution of transition arrays for the Super Transition Arrays approach to the bound-bound opacity calculation. Their method is based on the representation of the photoabsorption coefficient as the Fourier transform, the linearity of the transition energy between configurations with respect to shell occupation numbers, and factorization of the probabilities of configurations on shell occupation numbers. We propose a simplified variant of Hazak–Kurzweil method for the calculations with Detailed Configuration Accounting. The resulting expressions for the bound-bound opacity represent an alternative to the widely used ones and are quite convenient for numerical implementation.

In this study, we examine three-dimensional (3D) modulated ion-acoustic waves (IAWs) and associated multi-rogue waves in a magnetoplasma consisting of kappa-distributed electrons and hot, anisotropic positive ions. By employing a reductive perturbation technique (the derivative expansion method), the fundamental fluid equations are reduced to the three-dimensional nonlinear Schrödinger equation (3D-NLSE) to investigate the 3D modulational instability (3D-MI) and associated modulated IAWs. For the plasma parameters of interest, such as the anisotropic parallel ion pressure, magnetic field (ion gyrofrequency), and the spectral index of the kappa distribution, the stable and unstable regions of modulated envelope structures are precisely identified. The criteria for the 3D-MI based on the 3D-NLSE are determined and numerically examined. Furthermore, the analytical and numerical solutions for first-order and second-order ion-acoustic rogue waves (IARWs) are investigated. The effects of relevant plasma parameters on the IARW profile are also examined. The implications of our findings for specific environments, such as Earth’s magnetosheath and magnetosphere, are also discussed.

Multidimentional MI and RWs in superthermal anisotropic plasma

The fluorescence turn-on mechanism of the quinazolinone-based probe HTPQC for selective cysteine (Cys) detection has been theoretically investigated. Electron–hole analysis indicates that HTPQC has a charge transfer distance (D-index) of 4.86 Å, suggesting significant intramolecular charge transfer (ICT). Additionally, the energy levels of the frontier molecular orbitals (FMOs) for both the donor and acceptor components do not support the occurrence of a photoinduced electron transfer (PET) process. These results illustrate that the weak fluorescence of the probe is mainly attributed to ICT, rather than the PET mechanism proposed in previous studies. Upon reaction with Cys, the product HTPQ shows a reduced D-index (4.59 Å) in its enol form, resulting in enhanced fluorescence at 534 nm. Subsequently, the enol form transforms into the keto form via excited-state intramolecular proton transfer (ESIPT), with a low energy barrier of 1.951 kcal mol⁻¹. In the keto form, complete charge separation occurs (D-index = 7.17 Å), and FMO analysis shows that the highest occupied molecular orbital (HOMO) of the acceptor is higher in energy than that of the donor, indicating PET-induced fluorescence quenching of HTPQ. This study provides a novel theoretical explanation for the photophysical mechanism of cysteine detection via the HTPQC probe, offering insights that diverge from previously established explanations.

Based on a two-dimensional compressible magnetohydrodynamic (MHD) model, we systematically investigated the individual effects and combined influence of localized out-of-plane antisymmetric flows and the Hall effect on magnetic reconnection dynamics. The results reveal that both the localized out-of-plane antisymmetric flow and the Hall effect rapidly trigger magnetic reconnection, but the maximum achievable energy conversion rate is reduced, indicating that the nonlinear evolution of reconnection in later stages is suppressed. Additionally, the out-of-plane antisymmetric flow suppresses the magnetic island coalescence observed in purely resistive tearing modes. The introduction of the Hall effect can accelerate the merger of magnetic islands within the current sheet. When combined with the out-of-plane antisymmetric flow's influence, it is shown that the interplay between the Hall effect and the z-axis-aligned out-of-plane antisymmetric flow forms magnetic islands within elongated current sheets, thereby inducing additional plasma instabilities. These findings contribute significantly to the understanding of tearing mode instability development under the coupled influences of outflow dynamics and Hall physics in MHD systems.

High-resolution optical spectroscopy of Rb atoms in an intermediate-Zeeman magnetic field regime is performed. Magnetic fields between 0.05 T and 0.13 T are measured. We introduce a measurement approach based on three-level (Lambda ) systems where the open-loop frequency energy separation is determined by the applied magnetic field. Using this method an accuracy better than 100 ppm is reached in a measurement series. In parallel, on the basis of complementary measurements based on three-level V systems we obtain the first experimental value of the Landé g-factor of the first excited state for (^{85})Rb, (^{85}g_J(5P_{1/2}))=0.66709(7), and for (^{87})Rb, (^{87}g_J(5P_{1/2}))=0.6663(2). Our approach is unprecedented in the literature for Rb.

Experimental results for the Land´e g-factor of the first excited state of Rb