Plasma Medium Research Articles

Numerical study on wave attenuation via 1D fully kinetic electromagnetic particle-in-cell simulations

Abstract Electromagnetic wave-plasma interaction has drawn much attention recently due to numerous important technologies and applications, taking advantage of phenomena such as electromagnetic waves being reflected or absorbed in a plasma medium. The physics of wave-plasma interaction can be complicated, when non-uniform, non-equilibrium, or anisotropic plasmas are involved, in which numerical simulations can be used to fill the gaps between theoretical solutions and experimental measurements. Among many numerical methods, the particle-in-cell method, which can solve accurately both the electromagnetic fields and particle trajectories
self-consistently, would be the best choice to study wave-plasma interaction problems as long as the computational cost can be accepted. However, the applications of PIC on wave-plasma interaction remain rare, and the numerical effects of the PIC method on accurately evaluating the wave attenuation have not been studied in depth. In this paper, a number of numerical parameters and physical parameters are tested using a 1D electromagnetic PIC method plus Monte Carlo collision model. It is found that as long the as the basic PIC criterion is met, the PIC results can be trustable, and the numerical noise due to limited number of particles has a minor effect. The physical parameters of the EM wave frequency, amplitude, the plasma temperature, thickness, and collision type are studied, and their effects on the wave attenuation are presented. In addition, strategies on establishing simulation setup and evaluating the wave attenuation in terms of power or energy are discussed.

Gravitational lensing around a dual-charged stringy black hole in plasma background

One of the strongest tools to verify the predictions of general relativity (GR) has been the gravitational lensing around various compact objects. Using a dual charged stringy black hole produced from dilaton-Maxwell gravity, we investigate the impact of the plasma parameter on gravitational lensing and black hole shadow in this study. Detailed investigations are performed to mark the impact of the homogeneous and non-homogeneous plasma environment on the electric and magnetic charge parameters of stringy black hole. In order to compare the results, we have also considered the vacuum scenario of the dual charged stringy black hole. Our results show that the effect of homogeneous plasma environment is much stronger in comparison to vacuum for the case of electrically charged stringy black hole. However, in the case of magnetically charged stringy black hole, the deflection angle gets decreased in presence of the homogeneous plasma medium. It has been observed that the radius of the shadow increases in a non-homogeneous plasma environment for electrically charged stringy black hole, whereas it decreases for magnetically charged stringy black hole in presence of the same plasma environment. This study aims to investigate how different plasma environments influence these fascinating astrophysical phenomena.

Deflection angle and quasi-periodic oscillations of extended gravitational decoupled black hole solution

Abstract In weak field limits, we compute the deflection angle of gravitational decoupling extended black hole Solution black hole solution. We obtained the Gaussian optical curvature by examining the null geodesic equations with the help of Gauss–Bonnet theorem. We also looked into the deflection angle of light by black hole in weak field limits with the use of the Gibbons Werner method. We verify the graphical behaviour of the black hole after determining the deflection angle of light. Additionally, in the presence of the plasma medium, we also determine the deflection angle of the light and examine the graphical behaviour. Further, we compute the Einstein ring via gravitational decoupling extended black hole solution. We also compute the quasi-periodic oscillations and discuss their graphical behaviour.

Effect of anisotropy on the formation of heavy quarkonium bound states

We study the real part of the static potential of a heavy quark-antiquark system in an anisotropic plasma medium. We use a quasiparticle approach where the collective dynamics of the plasma constituents is described using hard-loop perturbation theory. The parton distribution function is characterized by a set of parameters that can accurately describe the anisotropy of the plasma produced in a heavy ion collision. We calculate the potential numerically in strongly anisotropic systems and study the angular dependence of the distortion of the potential relative to the isotropic one. We obtain an analytic expression for the real part of the heavy quark potential in the limit of weak anisotropy using a model that expresses the potential in terms of effective screening masses that depend on the anisotropy parameters and the orientation of the quark-antiquark pair. A one-dimensional potential is formulated in terms of angle averaged screening masses that incorporate the anisotropy of the medium into a radial coordinate. We solve the corresponding Schrödinger equation and show that the magnitude of the binding energy typically increases with anisotropy. Anisotropy can play an important role, especially in states with nonzero angular momentum. This means that the number of bound states that are formed could depend on specific characteristics of the anisotropy of the plasma. Our study suggests that plasma anisotropy plays an important role in the dynamics of heavy quarkonium and motivates further study. Published by the American Physical Society 2024

Investigating the weak gravitational lensing in Starobinsky–Bel–Robinson gravity black hole

This paper is motivated to study the weak gravitational lensing of the black hole in the context of Starobinsky–Bel–Robinsion gravity. We deduce the deflection angle of light in the weak field limits. For this purpose, we find the Gaussian curvature and apply the Gauss–Bonnet theorem. We also investigate the deflection angle at which light is deflected by a plasma medium. Furthermore, we analyze the graphical behavior of the deflection angle in the framework of SBR gravity. We also calculate the energy extracted from the black hole in SBR gravity, Einstein ring, and lens equation in the non-plasma and plasma framework. We conclude this study with a discussion of how light beams behave when they approach such a four-dimensional black hole by calculating the deflection angle.

Plasma impact on black hole shadow and gravitational weak lensing in Einstein-Maxwell-scalar theory

Abstract In this paper, we investigate the optical properties of a non-rotating charged black hole (BH) in the Einstein-Maxwell-scalar (EMS) theory, together with a plasma medium. We first consider the photon sphere and shadow radius under the impact of the plasma medium existing in the environment surrounding the BH in EMS theory. We show that the radius of the photon sphere and the BH shadow decrease under the influence of the parameter $\beta$. We further study the gravitational weak lensing in detail by adapting general methods and derive the light ray's deflection angle around the BH together with the plasma environment. It is found that for uniform plasma, the deflection angle increases with the rise of the plasma parameter, whereas it decreases with the increase of the plasma parameter for non-uniform plasma. Besides, we also study the magnification of image brightness.

Tumor microenvironment-like conditions alter pancreatic cancer cell metabolism and behavior.

The tumor microenvironment is complex and dynamic, characterized by poor vascularization, limited nutrient availability, hypoxia, and an acidic pH. This environment plays a critical role in driving cancer progression. However, standard cell culture conditions used to study cancer cell biology in vitro fail to replicate the in vivo environment of tumors. Recently, "physiological" cell culture media that closely resemble human plasma have been developed (e.g., Plasmax, HPLM), along with more frequent adoption of physiological oxygen conditions (1%-8% O2). Nonetheless, further refinement of tumor-specific culture conditions may be needed. In this study, we describe the development of a tumor microenvironment medium (TMEM) based on murine pancreatic ductal adenocarcinoma (PDAC) tumor interstitial fluid. Using RNA-sequencing, we show that murine PDAC cells (KPCY) cultured in tumor-like conditions (TMEM, pH 7.0, 1.5% O2) exhibit profound differences in gene expression compared with plasma-like conditions (mouse plasma medium, pH 7.4, 5% O2). Specifically, the expression of genes and pathways associated with cell migration, biosynthesis, angiogenesis, and epithelial-to-mesenchymal transition were altered, suggesting tumor-like conditions promote metastatic phenotypes and metabolic remodeling. Using functional assays to validate RNA-seq data, we confirmed increased motility at 1.5% O2/TMEM, despite reduced cell proliferation. Moreover, a hallmark shift to glycolytic metabolism was identified via measurement of glucose uptake/lactate production and mitochondrial respiration. Taken together, these findings demonstrate that growth in 1.5% O2/TMEM alters several biological responses in ways relevant to cancer biology, and more closely models hallmark cancerous phenotypes in culture. This highlights the importance of establishing tumor microenvironment-like conditions in standard cancer research. NEW & NOTEWORTHY Standard cell culture conditions do not replicate the complex tumor microenvironment experienced by cells in vivo. Although currently available plasma-like media are superior to traditional supraphysiological media, they fail to model tumor-like conditions. Using RNA-seq analysis and functional metabolic and migratory assays, we show that tumor microenvironment medium (TMEM), used with representative tumor hypoxia, better models cancerous phenotypes in culture. This emphasizes the critical importance of accurately modeling the tumor microenvironment in cancer research.

Shadow and gravitational weak lensing for quantum improved charged black hole in plasma* *Supported partly by Grants F-FA-2021-432, F-FA-2021-510, and MRB-2021-527 of the Ministry of Higher Education, Science and Innovations of the Republic of Uzbekistan

We investigated the shadow and weak gravitational lensing for the quantum-improved charged black hole (BH). First, the photon motion and BH shadow were studied in a plasma medium. It can be seen from our analysis that the radius of the photon sphere of the quantum-improved charged BH and size of the BH shadow decrease under the influence of the plasma parameter . Furthermore, the gravitational weak lensing is considered for the quantum-improved charged BH, and we have obtained the deflection angle of light rays around a compact object for uniform and non-uniform plasma cases. It is shown that the value of the deflection angle for uniform plasma increases with increasing plasma parameter, and vice versa for non-uniform plasma. It has been also indicated that under the influence of the plasma parameter and BH charge , the values of the deflection angles for the two cases decrease. Finally, we investigated the magnification of image brightness using the deflection angle of the light rays around the quantum-improved charged BH.

A numerical study of gravity-driven instability in strongly coupled dusty plasma. Part 3. Homo-interaction between a pair of rising/falling bubbles/droplets

A numerical study of the homo-interactions between two falling droplets and between two rising bubbles in a strongly coupled dusty plasma medium is presented in this article. The strongly coupled dusty plasma is considered as a viscoelastic fluid using the generalized hydrodynamic fluid model formalism. Two factors that affect homo-interactions are taken into account: the initial spacing and the coupling strength of the medium. Three different spacings between two droplets are simulated: widely, medium and closely. In each case, the coupling strength has been given as mild–strong and strong. It is shown that the overall dynamic is governed by the competition between the acceleration of two droplets/bubbles due to gravity and the interaction due to the closeness of the droplets/bubbles. Particularly in viscoelastic fluids, apart from the initial separation, shear waves originating from rotating vortices are responsible for the closeness of two droplets or bubbles. Several two-dimensional simulations have been carried out. This work is a continuation of the work done in Parts 1 (Dharodi & Das, J. Plasma Phys., vol. 87, issue 2, 2021, 905870216) and 2 (Dharodi, J. Plasma Phys., vol. 87, issue 4, 2021, 905870402).

The effect of the external magnetic field on the power of the laser passing through the magnetized plasma and the calculation of the radius of convergence and the investigation of the condition of the beam's filamentation in the Medium

In this article, the power of a laser passing through a magnetized plasma medium which is affected by an external magnetic field is calculated.The change in the intensity of the magnetic field and its rotation around the axis of laser beam propagation in the plasma, on the power of the passing beam is investigated.This work is done based on the indirect effect of the magnetic field on the density distribution of electrons in the plasma, which we can consider the density changes as changes in the refractive index of the medium, so the laser power in this case is different from the case where there is no magnetic field. Also, the condition of beam filamentation has been researched as one of the third-order nonlinear phenomena, and the convergence radius has been calculated under these conditions.

Evolution of light deflection and shadow from a gauge-potential-like AdS black hole under the influence of a non-magnetic plasma medium

We investigate the light deflection in the weak field approximation from the accelerating charged AdS black hole. For this purpose, we apply the Gauss–Bonnet theorem to calculate the light deflection in the weak field area and use the Gibbons–Werner approach to analyze the optical geometry of the accelerating charged AdS black hole in the non-magnetic plasma absence/presence of a non-magnetic medium. We also represent the graphical behavior of the light deflection angle w.r.t. the impact parameter. We also compute the light deflection angle using Keeton and Petters approximations under the impact of accelerating charged AdS black hole geometry. Furthermore, by using the ray-tracing approach, we determine the shadow in the non-magnetic plasma presence and also demonstrate that graphical shadow has an impact on the gauge potential, non-magnetic plasma frequencies and charge.

Study of deflection angle and shadow in supergravity black hole theory under the influence of non-magnetic plasma medium

In this paper, we examine models of a black hole’s deflection angle in the context of gauged super-gravity, using the black hole’s optical metric. We compute Gaussian curvature and the Gauss-Bonnet theorem of optical metric and also follow the Gibbons-Werner technique to calculate the deflection angle. The spacetime curvature effects are significant and will have extensive implications for gauged supergravity theory. By incorporating the Gaussian curvature of the optical metric over a four-dimensional surface of light dispersion. Further, we examine the deflection angle in the presence of the non-magnetic plasma medium and how the non-magnetic plasma impacts the deflection angle. Furthermore, we show how the photon sphere influences the gauged supergravity and non-magnetized plasma of the black hole shadow, as well as how to generate black hole shadows by employing the ray tracing approach. Finally, we analyze the shadow cast and address plots of both the deflection angle and the shadow to understand the deflection angle functions and the shadow impact in the non-magnetic plasma medium.

Enhanced plasma ion heating by lasers in inhomogeneous external magnetic field

Particle–In–Cell simulations have been carried out to study the propagation of a laser pulse inside a plasma medium threaded with an external magnetic field. The external magnetic field is chosen to have space variations, which ensure that the laser pulse penetrates inside the plasma slab following the pass band dispersion relation of the X-mode. The spatial variation of the magnetic field is chosen such that the LH resonance is encountered within the bulk plasma medium. Enhanced deposition of laser energy to ions at the resonance layer has been demonstrated. This scheme would thus be useful to heat ions at any desired bulk region of the plasma.

Effect of carbon infusion on water splitting performance of (Ni0.2 Co0.2 Cr0.2 Mn0.2 V0.2)3O4 high entropy oxides nanoparticle synthesized via thermal plasma

A high entropy oxides (HEOs) has been proposed as a promising electrocatalyst for electrochemical water splitting reaction owing to their distinctive catalytic activity, stability, and tuneable electronic structure. In this work, a carbon infused HEOs (Ni0.2 Co0.2 Cr0.2 Mn0.2 V0.2)3O4 nanoparticles were synthesized via a single step process through a carbonaceous thermal plasma (Ar-CO2CH4) medium. Here, carbon infused HEOs were utilized as an electrocatalyst for water splitting reaction in 1 M KOH electrolyte. A Carbon rich HEOs (HEO C6) nanoparticle exhibits excellent oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) performance with an overpotential of 243 and 217 mV to attain a current density of 50 mA cm-2, respectively. The fabricated two-electrode device requires only a 1.596 V as cell voltage to meet a current density of 10 mA cm-2. This study provides a new platform for a large-scale hydrogen production by utilizing carbon supported HEOs as an electrocatalyst.

Exploring cosmic ray energy loss mechanisms: Insights from Bethe-Bloch, modified bethe-bloch, and inverse compton scattering equations

This study delves into the intricate dynamics of cosmic ray energy loss mechanisms, employing three distinct mathematical approaches: the Bethe-Bloch equation, the modified Bethe-Bloch equation, and the inverse compton scattering equation. The Bethe-Bloch equation elucidates the ionization and bremsstrahlung processes governing cosmic ray interactions with plasma mediums, providing foundational insights into energy loss phenomena. Expanding upon this, the modified Bethe-Bloch equation integrates additional factors such as medium density and magnetic fields, refining our understanding of cosmic ray propagation in diverse astrophysical environments. Moreover, the inverse Compton scattering equation uncovers the energy loss mechanisms associated with cosmic ray interactions with photons in the interstellar medium, contributing essential insights into high-energy astrophysical phenomena. Through mathematical derivations, numerical computations, and graphical analyses, our investigation reveals the intricate dependencies of final cosmic ray energy on various parameters, including initial energy, target photon density, and magnetic field strength. Furthermore, our findings have broader implications for astrophysical processes such as gamma-ray emission and cosmic-ray acceleration mechanisms. By elucidating the complex interplay between cosmic rays and their surrounding environments, this study advances our understanding of high-energy astrophysical phenomena and provides a framework for future research in this field.

Triglyceride-rich lipoprotein, remnant cholesterol, and apolipoproteins CII, CIII, and E in patients with schizophrenia

Patients with schizophrenia show a disproportionally increased risk of cardiovascular disease. Hypertriglyceridemia is prevalent in this population; however, how this relates to levels of remnant cholesterol, triglyceride (TG)-rich lipoprotein (TRL) particle size and composition, TG turnover, and apolipoprotein (apo) and angiopoietin-like protein (ANGPTL) concentrations is unknown. Fasting levels of cholesterol (total [TC], LDL-C, HDL-C, non-HDL-C and remnant cholesterol) and TG were determined in 110 patients diagnosed with schizophrenia, and 46 healthy controls. TRL particle size, concentration and composition, and β-hydroxybutyrate (TG turnover marker) were assessed by NMR. Levels of apoCII, apoCIII, apoE, ANGPTL3, ANGPTL4, and ANGPTL8 were measured by ELISA, and apoCII, apoCIII and apoE were further evaluated in HDL and non-HDL fractions. Patients with schizophrenia had significantly elevated TG, TG:apoB ratio, non-HDL-C, remnant cholesterol, non-HDL-apoCII and non-HDL-apoCIII, and HDL-apoE (all P < 0.05), lower HDL-C and apoA-I (all P < 0.001), and comparable apoB, TC, TC:apoB ratio, LDL-C, β-hydroxybutyrate, ANGPTL3, ANGPTL4 and ANGPTL8 to healthy controls. Patients had a 12.0- and 2.5-fold increase in the concentration of large and medium TRL particles respectively, but similar cholesterol:TG ratio within each particle. Plasma TG, remnant cholesterol, and large and medium TRL particle concentrations correlated strongly with apoCII, apoCIII, and apoE in the non-HDL fraction, and with apoCIII and apoE in the HDL fraction in patients with schizophrenia. Differences in TG, HDL-C, TRL particle concentrations, apoCIII, and apoE persisted after adjustment for conventional risk factors. These results are consistent with impaired TRL lipolysis and clearance in patients with schizophrenia which may be responsive to targeting apoCIII.

Laboratory simulation to study the nonlinear evolution of right-hand circularly polarised wave in laser-produced plasmas

To simulate the astrophysical scenarios at the scale of laboratory astrophysics, the interaction of high-power lasers with plasmas is increasingly being used. So, in this perspective, a nonlinear wave-wave interaction between right-hand circularly polarised wave (R-mode wave) and electron plasma wave (EPW) is proposed to understand the localization of the pump R-mode wave and associated magnetic turbulence at electron scale in magnetized plasma relevant to laboratory astrophysics. The ponderomotive force and relativistic variation of electron mass are accountable for this nonlinear wave-wave interaction model. For this nonlinear dynamics, coupled model equations for EPW and R-mode wave are developed and solved by laboratory simulations utilizing finite difference and pseudo-spectral methods. The observed simulation findings, like the nonlinear evolution of the pump wave, typical scale size of the formed localized structures, and electron scale turbulent spectra associated with the coherent structures resemble various laboratory and space plasma scenarios. A semi-analytical model in the paraxial limits is also developed to understand the physics behind the localization process of the pump wave inside the plasma medium.

Effect of magnetized plasma on shadow and gravitational lensing of a Reissner–Nordström black hole

We explore the influence of the axion–plasmon on the optical properties of the charged black hole and show how the axion–plasmon coupling modifies the motion of photons around the charged black hole. We then explore in details observational effects such as the black hole shadow, the gravitational deflection angle, Einstein rings and shadow images obtained by radially infalling gas on a black hole within a plasma medium. An important finding is that the intensity of the electromagnetic radiation increases with the increase of charge and the size of the black hole shadow decreases with increase of the electric charge for a fixed axion–plasmon coupling values when observed from sufficiently large distance. Overall, for a constant value of charge the optical appearance of the black hole shadow depends on the surrounding plasma model and the largest shadow radius if found for the case of no plasma, while the smallest shadow radius is found for the case of homogeneous plasma.

Ground state properties of the screened helium atom under harmonic confinement

In this contribution, we show electronic property results for the ground state of the helium atom screened by a Debye plasma under an isotropic harmonic confinement as a function of the screening length (λD) and the angular frequency (ω0). The associate Hamiltonian is solved by expanding the wave function in the Hylleraas basis to incorporate the electron correlation in a simple manner. Furthermore, in order to compare with other findings the Hartree–Fock approach is implemented using a numerical grid method. The main results show that the total energy reaches the ionization threshold by the action of the electron coupling with the plasma medium and the strength of the harmonic confinement. The electron–electron average distance shows the compression of the system as the Debye plasma and the harmonic interactions become strongest (low λD and large ω0 values). We found acceptable results for the electron correlation energy when separate interactions are considered. In the absence of both interactions, the findings are in excellent agreement with other theoretical results.

Radiative corrections for factorized jet observables in heavy ion collisions

I look at the renormalization of the medium structure function and a medium induced jet function in a factorized cross section for jet substructure observables in Heavy Ion collisions. This is based on the formalism developed in [1], which uses an Open quantum system approach combined with the Effective Field Theory (EFT) for forward scattering to derive a factorization formula for jet observables which work as hard probes of a long lived dilute Quark Gluon Plasma (QGP) medium. I show that the universal medium structure function that captures the observable independent physics of the QGP has both rapidity and UV anomalous dimensions that appear due to medium induced Bremsstrahlung. The resulting Renormalization Group (RG) equations correspond to the BFKL equation and the running of the QCD coupling respectively. I present the first results for the numerical impact of resummation using these RG equations on the mean free path of the jet in the medium. I also briefly discuss the prospects of extending this formalism for a short lived dense medium.