Contributions to Plasma Physics最新文献

The present study explores the three-dimensional wave group dynamics and breather excitations associated with dust-acoustic waves (DAWs) in a superthermal magnetized dusty plasma system. The plasma is assumed to consist of inertialess electrons and ions obeying a kappa distribution, and a negatively charged inertial dust fluid under the influence of an external uniform magnetic field. By employing the reductive perturbation method, we derive the Laedke-Spatschek (LS) equation, which governs the dynamics of the nonlinear DAWs in such a plasma configuration. Analytical solutions of the evolution equation predict a wide class of nonlinear localized structures. Furthermore, the analysis reveals that the modulated wave group dynamics can be effectively described by a $���\left(��3�+�1��\right)��$-dimensional nonlinear Schrödinger equation (NLSE), accounting for both nonlinear and dispersive effects. The regions of stability and instability of the DAW propagation are delineated in the relevant plasma parameter space, identifying the conditions under which rational breather solutions of NLSE, such as the Peregrine soliton, Akhmediev breather, and Kuznetsov-Ma breather can be excited through modulational instability. The findings provide a comprehensive understanding of the proliferation of nonlinear wave modulation and energy localization phenomena in dusty plasma environments, with potential implications for both space and laboratory plasma systems.

Neutral particles in the plasma edge of a fusion device are governed by a kinetic equation that describes how the particles are distributed in space, velocity, and time. The kinetic equation incorporates various interactions between the neutral particles and the plasma particles, such as recombination reactions, ionization reactions, and charge–exchange reactions. These so-called neutral–plasma interactions can be described mathematically by linear operators. On the other hand, there are also (elastic) self-collisions between the neutral particles themselves. These so-called neutral–neutral interactions are often neglected as they turn the kinetic equation nonlinear. For realistic fusion devices, however, these interactions can have an important influence on simulation results. Here, we describe the kinetic equation including elastic neutral–neutral collisions and derive a reduced-order model, also called a fluid model, that takes this nonlinear effect into account. The accuracy of the reduced-order model is verified numerically.

The propagation of upper hybrid waves in partially degenerate quantum electron hole plasmas under weak magnetic fields is investigated within a linearized Vlasov Maxwell framework. Using Fermi Dirac statistics, a generalized dielectric response function is derived that incorporates finite temperature and degeneracy effects. The resulting dispersion relation describes high frequency modes near the plasma oscillation regime. Application to GaAs parameters shows that partial degeneracy and weak magnetization significantly modify the dispersion characteristics compared with classical predictions. Quantum statistics shift resonance conditions and introduce weak Landau damping through the imaginary part of the longitudinal permittivity. These results provide a consistent description of wave propagation in dense semiconductor plasmas relevant to weakly magnetized laboratory and nanoscale electronic systems.

This work presents a study of the coupling between lattice ion vibrations and electron waves in magnetized piezoelectric semiconductor quantum plasmas using the quantum hydrodynamic (QHD) model. A quantum modified dispersion relation has been derived, incorporating the quantum corrections and external magnetic field. A set of nonlinear evolution equations has been established through the application of the two-time scale theory, and a soliton solution for these coupled nonlinear evolution equations has been obtained using the modified quantum Zakharov equations. The obtained solitons exhibit cusp-like solitary structures, characterized by sharp, non-differentiable peaks. The findings reveal that the amplitude of the soliton field increases significantly with particle density, while it decreases with the strength of the magnetic field and piezoelectric coupling coefficient. Inclusion of exchange and correlation potential enhances localization, producing sharper soliton profiles. These findings demonstrate that magnetic field and quantum effects provide effective control over soliton dynamics and wave transmission.

The computational cost of finding the optimal design of plasma wakefield acceleration (PWFA) is usually very demanding due to many variables involved. Herein, we have developed a novel framework which combines Bayesian optimization (BO) with neural network (NN), to replace computationally expensive simulation software and provide a more efficient way for the optimization process. In order to verify this framework, the AWAKE Run 2 experiment at CERN is used as an example. In the framework we constructed, the coefficients of determination ($��R^2�$) of NN reaches above 0.99, and the time-to-solution reduces to a factor of 35.6. For the first time, BO combined with NN is successfully applied to optimize PWFA and significant improvements have been demonstrated. The framework established here in principle can also be extended to the optimization of other particle accelerations.

The advancement of 3D integration technology has driven demand for micro-scale, high aspect ratio (HAR) through-silicon via (TSV) etching, establishing it as a critical semiconductor manufacturing technology. Current 3D stacking implementations typically utilize TSVs with aspect ratios of approximately 10:1. To enable higher-density interconnects in next-generation applications, achieving substantially higher AR TSVs is imperative. However, within the photoresist (PR) mask system, high aspect ratio TSV etching faces challenges of insufficient etch selectivity and PR mask collapse, both of which constrain further aspect ratio scaling. This study proposes an optimization strategy for key process parameters. Through parametric optimization of chamber pressure, source power, and bias power, we achieved significant enhancement in selectivity and completely eliminated PR mask collapse. Ultimately, an aspect ratio of 25:1 was successfully demonstrated on TSVs with a critical dimension (CD) of 3 μm.

We present a thermodynamically consistent derivation of generalized Saha relations for stationary multi-temperature plasmas using a maximum entropy framework applied to systems coupled to multiple thermal reservoirs. By explicitly constraining distinct subsets of degrees of freedom, we obtain a generalized affinity relation appropriate for nonequilibrium stationary states and recover known two-temperature Saha forms as particular cases. The approach provides a transparent statistical interpretation of ionization equilibria in multi-temperature plasmas.