Contributions to Plasma Physics最新文献

We summarize the method of hydrodynamic approximation for weakly ionized plasmas developed with Klimontovich in 1962 and give a generalization to many—component systems using Onsagers matrix theory and including dispersion effects. We develop the conductivity theory of complex plasma and electrolyte mixtures based on the model of charged hard spheres with given non-additive contact distances, including frequency-dependent electric fields. These generalizations are made with the aim to allow applications to complex natural systems as atmospheric plasmas and seawater. Finally, we give as an example a numerical calculation of the single ion conductivities of a six-component seawater model.

(a) Electron current density, z-component; (b) Electric field intensity (V/m); filament line: electron flow. Fig.6 of the paper by Yiqun Ma et al. https://doi.org/10.1002/ctpp.202300169

Partially detached H-modes are the baseline regime for the future ITER operation. The ASDEX Upgrade partially detached H-mode is modeled using the SOLPS-ITER code with drifts enabled and compared with experimental data. For the first time, boron (B) impurity is simulated in the Scrape-off layer (SOL) and divertor. A comparison between divertor diagnostics and discrepancies between Langmuir probe and Divertor Thomson scattering/Stark broadening diagnostic are discussed. In the modeling, experimental target profiles are reproduced if the experimental level of radiation in the SOL and divertor is achieved using nitrogen (N) impurity seeding. Bolometry measurements detect substantial radiation from the partially detached outer strike point. With B radiation, this maximum in bolometry data is reproduced in the modeling, which is not possible with N alone.

A first principle molecular dynamics (MD) simulation study on the nonlinear excitations in a quasi-localized state of a Yukawa system is presented to validate the findings of the nonlinear quasi-localized charge approximation (QLCA) model. Unlike solids or gases, quasi-localized states lack certain simplifying features, such as the ability to assume a fixed shape or volume, and they combine large displacements with strong interactions, further complicating the theoretical underpinnings of their behavior. In a recent paper [P. Kumar and D. Sharma, Physics of Plasmas 30 (2023)], the nonlinear QLCA model was applied to characterize the nonlinear excitations in a quasi-localized state of a Yukawa system, as existing continuum models have shown limited success in this regime. The simulation data presented with the screening and coupling parameters show a close agreement with the QLCA model findings. The MD simulations validate the prediction made by the QLCA model that the properties of a soliton remain unaffected by variations in the coupling parameter. The prediction made by QLCA regarding the formation of multiple solitons at higher screening parameter values has also been confirmed by the MD simulation data. The possibility of the formation of rarefactive solitons at relatively high screening parameter values within the QLCA model is also discussed.

The BBGKY hierarchy in the Wigner representation is used with an extended Singwi-Tosi-Land-Sjölander (STLS) ansatz for the two-particle distribution function [H. Kählert, G. J. Kalman, and M. Bonitz, Phys. Rev. E 90, 011101 (2014)] to study the density response function and the dispersion relation of collective modes in a strongly coupled quantum system. It is shown that the local field correction (LFC) and the dispersion relation reduce to the results of the Quasi-Localized Charge Approximation (QLCA) in the classical limit. In the quantum case, the LFC acquires a frequency-dependence, similar to the quantum version of the STLS theory. The dispersion relation is governed by a generalization of the QLCA dynamical matrix. The results are expected to be relevant for the analysis of collective modes in quantum liquids with strong correlations.