Electrostatic Structures Research Articles

Regulating Functional Groups to Construct a Mild Passivator Enhancing the Efficiency and Stability of Carbon-Based Perovskite Solar Cells.

The abundant defects on the perovskite surface greatly impact the efficiency improvement and long-term stability of carbon-based perovskite solar cells. Molecules with electron-donating or electron-withdrawing functional groups have been cited for passivating various defects. However, few studies have investigated the potential adverse effects arising from the synergistic interactions among functional groups. Herein, we investigate the correlation between functional group configurations and passivation strength as well as the potential adverse impacts of strong electrostatic structures by methodically designing three distinct interface molecules functionalized with different ending groups, which both belong to biguanide derivatives, including 1-(3,4-dichlorophenyl) biguanide hydrochloride (DBGCl), metformin hydrochloride (MFCl), and biguanide hydrochloride (BGCl). The results indicate that DBGCl establishes comparatively mild active sites, not only passivates defects but also aids in forming a surface with a uniform potential. Conversely, MFCl exerts a more pronounced adverse effect on the perovskite surface, which is attributable to the electronic state perturbations induced by its functional groups. Due to the lack of hydrophobic groups, devices treated with BGCl demonstrate insufficient moisture resistance. Devices passivated with DBGCl demonstrate superior average efficiency, showcasing a 12% enhancement relative to the pristine. Furthermore, DBGCl-treated devices exhibit enhanced stability in three different environments, respectively, achieving the highest PCE retention rates under nitrogen conditions (25 °C), room-temperature air conditions (25 °C, RH = 40 ± 2%), and high-temperature air conditions (65 °C, RH = 40 ± 2%).

Construction of polymer-derived double transition metal compound/carbon matrix nanocomposites for efficient electromagnetic wave absorber

As typical dielectric materials, transition metal compounds have a broad potential in the field of stealth, but their application is still hampered by poor conductivity. In this study, based on the mechanism of electrostatic self-assembly of heteropolyacids and organic ligands, the electrostatic structures obtained after the introduction of different heteropolyacids into the conductive phase pyrrole are carbonized. On the one hand, the as-prepared transition metal compounds/carbon matrix nanocomposites produce synergistic effects and optimize impedance matching, and on the other hand, the formation of the abundant heterogeneous interfaces as well as the doping of the N, P heteroatoms induce the generation of interfacial polarisation and dipole polarisation, all of which provide the opportunities to produce composites with enhanced electromagnetic wave absorption properties. Unsurprisingly, the best synthesised sample, Mo2C/W2C/NPC, exhibits a significantly improved electromagnetic wave absorption performance, with an effective bandwidth of 5.7 GHz at a matched thickness of 2.5 mm, where the minimum reflection loss value of −54.5 dB is also achieved. The total effective bandwidth of the Mo2C/W2C/NPC-35 wt% is up to 10.5 GHz (7.3–17.8 GHz) via adjusting the matching thickness in the range of 1.7–3.5 mm. Therefore, this study reflects that dual transition metal compound/carbon based composite wave-absorbing materials provide a new material basis for the construction of high-performance absorption materials.

Oblique Electrostatic Solitary and Supersolitary Waves in Earth’s Magnetosheath

Nonlinear electrostatic solitary waves (ESWs) are routinely detected at various regions of Earth’s magnetosphere using the Wideband Data plasma wave receivers mounted on board the Cluster satellite(s). This mission has facilitated the observation and analysis of ESW characteristics, such as amplitude and temporal duration within the magnetosheath, while concurrently determining the density and temperature profiles of energetic electrons. These electron parameters, in conjunction with data from ion experiments, have served as input for the ion-acoustic solitary wave model developed in this article, with the ambition to contribute to the understanding of ESW generation mechanisms. Assuming as the starting point a plasma system comprising inertial ion fluid and kappa-distributed electron populations of different temperatures (i.e., “cold” and “hot” electrons), a nonperturbative approach has been adopted to investigate the existence and properties of solitary waves. A thorough parametric investigation has scrutinized the existence conditions for such localized structures in terms of the plasma configuration parameters. An interesting aspect emerges from the analysis, namely, the possibility for the coexistence of positive and negative polarity structures associated with ion-acoustic modes, in fact, manifested as simultaneously occurring positive polarity supersolitary waves and negative polarity regular solitary waves. Furthermore, our study has investigated the combined effect of the magnetic field strength, electron density, and suprathermal electron statistics on wave dynamics. The outcomes of this research are in agreement with observed electrostatic wave phenomena in the magnetosheath region, thus underscoring the intrinsic relevance of electrostatic supersolitary structures in data obtained by Cluster and other satellite missions.

Evolution of Subsonic Shock Waves Associated with Reconnection Jets in Earth’s Magnetotail

Motivated by the signatures of nonlinear electrostatic waves observed by the Magnetospheric Multiscale spacecraft mission in reconnection jet regions of Earth's magnetotail, we have explored the dynamical features of ion-acoustic shock waves in the magnetotail. In this investigation, we have examined the dynamics and characteristics of ion-acoustic subsonic shock waves in non-Maxwellian space plasma comprising of two counterstreaming ion beams with suprathermal electrons, assumed to follow a kappa (κ) distribution. A reductive perturbation technique has been adopted to establish an evolution equation for small amplitude electrostatic shock structures. Importantly, subsonic waves only exist when the beam velocity exceeds a certain threshold, beyond which supersonic and subsonic waves may coexist. The combined effects of the beam velocity and the non-Maxwellian electron statistics have been analyzed to examine the characteristics of subsonic shock waves. Both symmetric and asymmetric (in relative beam density) models have been considered, leading to distinct possibilities in the evolution of subsonic shock waves. The findings of the investigation will help unfold the relatively unexplored dynamical characteristics of subsonic shock waves that may form and propagate in the magnetosphere.

Juno Plasma Wave Observations at Europa

AbstractJuno passed by Europa at an altitude of 355 km on 29 September, day 272, 2022. As one of Juno's in situ science instruments, the Waves instrument obtained observations of plasma waves that are essential contributors to Europa's interaction with its environment. Juno observed chorus, a band at the upper hybrid frequency providing the local plasma density, and electrostatic solitary structures in the wake. In addition, impulses due to micron‐sized dust impacts on Juno were recorded with a local maximum very close to Europa. The peak electron density near Europa was ∼330 cm−3 while the surrounding magnetospheric density was in the range of 50–150 cm−3. There was a significant separation between the Europa flyby and Juno's crossing of Jupiter's magnetic equator, enabling a unique identification of effects associated with the moon as opposed to magnetospheric phenomena normally occurring at the magnetic equator near 10 Jovian radii.

Modulational instability of dust-ion acoustic waves in generalized (r, q) distributed electron dissipative plasmas

The modulational instability of the dust-ion acoustic waves in a dissipative dusty plasma system containing warm ions, generalized ( r , q ) distributed electrons, and immobile dust grains has been studied. The Krylov–Bogoliubov–Mitropolsky (KBM) perturbation method is employed to analyze the amplitude modulation of a monochromatic plane wave through the derivation of a nonlinear Schrödinger equation. This equation is solved analytically to determine the modulational instability region, and the corresponding dissipative rogue wave solution is obtained. The effects of various system parameters, such as the kinematic viscosity of the ions (υ), the wavenumber (k), the ion to electron temperature ratio ( σ i ), the unperturbed ion to electron density ratio (γ) as well as the electron distribution parameters: r and q, are investigated. The dependence of the amplitude of dissipated rogue waves on υ is discussed. It is found that various system parameters have significant effects on the features of dissipated rogue waves. The present investigation can be relevance to the electrostatic rogue structures in various cosmic dust-laden plasmas such as Saturn's F-ring.

On the shock wave structures in anisotropy magnetoplasmas

In this work, the propagation of nonlinear electrostatic shock wave structures in an anisotropy pressure magnetoplasma composed of warm inertial ions and inertia-less Maxwellian electrons is reported. For this purpose, the technique of reductive perturbation is applied for reducing fluid equations of the current model to the Korteweg–de Vries Burgers (KdVB) equation with a second-order dissipative term and the KdVB–Kuramoto (KBK) equation with both second- and fourth-order dissipative terms. The impact of various plasma parameters, including the parallel ion pressure, perpendicular ion pressure, and dissipation parameter, on the significant characteristics of the shock wave profile is examined and discussed. In addition, a comparison between the profiles of KdVB shocks and KdVB–Kuramoto shocks is reported. We expect that KBK shock wave amplitudes become larger than the KdVB ones by taking the fourth-order dissipative into consideration. Thus, the results of the KBK equation may treat the difference between the theoretical and laboratory results or satellite observations.

Langmuir Forcing and Collapsing Subsonic Density Cavitons via Random Modulations

Electrostatic nonlinear random Langmuir structures have been propagated in stochastic magnetospheres, clouds and solar wind. A theoretical description of Langmuir waves can be modeled by Schrödinger and Zakharov models with stochastic terms. It was explained that the stochastic parameter affects the forcing, collapsing in strongly density turbulence and density crystalline structures. The unified method has been implemented to provide new stochastic solutions for a Zakharov system in subsonic limit with noises via the Itô sense. This unified approach provides a variety of advantages, such as avoiding difficult calculations and explicitly providing pivotal solutions. It is easy to use, efficient, and precise. The induced generated energy during the collapsing of solar Langmuir wave bursts and clouds is determined by the solitonic formations. In addition, the collapsing strong turbulence or forcing density crystalline structures depend mainly on stochastic processes. Furthermore, electrostatic waves in clouds that may collapse are represented sometimes as dissipative shapes. So, the results of this investigation could be applicable to observations of energy seeding and collapsing in clouds. This energy is based on the electrostatic field and its related densities’ perturbation in subsonic limits. Finally, it has been explored how noise parameters in the Itô sense affect the solar wind Langmuir waves’ properties. So, the findings of this discussion may be applicable to real observations of energy collapsing and seeding in clouds.

A Mechanism for Large-Amplitude Parallel Electrostatic Waves Observed at the Magnetopause

Large-amplitude electrostatic waves propagating parallel to the background magnetic field have been observed at the Earth’s magnetopause by the Magnetospheric Multiscale (MMS) spacecraft. These waves are observed in the region where there is an intermixing of magnetosheath and magnetospheric plasmas. The plasma in the intermixing region is modeled as a five-component plasma consisting of three types of electrons, namely, two counterstreaming hot electron beams and cold electrons, and two types of ions, namely, cold background protons and a hot proton beam. Sagdeev pseudo-potential technique is used to study the parallel propagating nonlinear electrostatic solitary structures. The model predicts four types of modes, namely, slow ion-acoustic mode, fast ion-acoustic mode, slow electron-acoustic mode and fast electron-acoustic modes. Except the fast ion-acoustic mode, all other modes support solitons. Whereas slow ion-acoustic solitons have positive potentials, both slow and fast electron-acoustic solitons have negative potentials. For the case of 4% cold electron density, the slow ion-acoustic solitons have electric field ∼(40–120) mV m−1. The fast Fourier transforms (FFT) of slow ion-acoustic solitons produce broadband frequency spectra having peaks between ∼100 Hz to 1000 Hz. These theoretical predictions are in good agreement with the observations. The slow and fast electron-acoustic solitons could be relevant in explaining the low-intensity high (>1 kHz) frequency waves which are also observed at the same time.

Some electrostatic structures of the mKP equation for a nonthermal plasma system by a unified solver technique

The reductive perturbation technique is used to obtain the Modified KP equation at critical densities distinguished by the MKPE in plasma ion pair with fast electron positron. The new structures reveal that super-solitary and period waveforms are derived via the mathematical analysis of Jacobi-elliptic function expansions (MJEFE) for MKPE. The electrostatic new structures such as super-soliton, cnoidals, shock-like, super-dispersive and superperiodic plasma waves which existed at critical densities have been introduced. The positrons (electron) nonthermality supports on nonlinear dispersive new structures have been discussed. Also, many of the obtained electrostatic solutions are important and may be applicable in ionosphere plasma observations.

Solitary wave solution of (3+1)-dimensional cylindrical Kadomstev–Petviashvili equation in warm opposite polarity dusty plasma

A theoretical investigation is done to study the propagation of dust-acoustic (DA) solitary waves in a dusty plasma system containing dynamic positively as well as negatively charged warm dust species and nonthermally distributed ion and electron species. The standard reductive perturbation method is employed to derive the (3+1)-dimensional cylindrical Kadomstev–Petviashvili (KP) equation (also known as cylindrical Korteweg–de Vries equation), which admits solitary wave solution for small but finite amplitudes. The parametric regimes for the existence of DA solitary waves are obtained. Two modes, namely, slow and fast are observed corresponding to different phase velocities. The slow mode has negative solitary pulses, whereas the fast mode contains both positive and negative DA solitary waves. It is shown that the ratio of positively charged dust to negatively charged dust number density significantly modifies the basic features of the DA solitary waves. The noteworthy effects of other parameters (viz. the nonthermal parameter and ion-to-electron temperature ratio) on the basic properties (namely, phase speed, polarity, amplitude, and width) of the DA solitary waves are also mentioned. The fundamental features and the underlying physics of the electrostatic solitary structures that are relevant to cometary tails, upper mesosphere, Jupiter’s magnetosphere, etc., are briefly discussed.

Magnetic Perturbations in Electron Phase‐Space Holes: Contribution of Electron Polarization Drift

AbstractElectron phase‐space holes, sometimes referred to as electron holes, are Debye‐scale plasma structures commonly observed in space plasmas. Although they are usually thought of as electrostatic structures, recent observations have shown that these structures are often accompanied by magnetic field perturbations. Such magnetic perturbations may originate from Lorentz transformation of the electric field, although it has been also suggested that localized currents caused by the electron E × B motion may also play a role. In this paper, we consider the contribution of electron polarization drift to the current and therefore the magnetic field perturbations, which is validated by comparison to Magnetospheric MultiScale observations of 69 electron holes based on a superposed epoch technique. Our results show that the magnetic perturbations caused by the electron polarization drift can be significant compared to Lorentz transformation effect, especially in regions with low magnetic strength and large electron density.

Nonlinear electrostatic structures and stopbands in a three-component magnetosheath plasma

Nonlinear electrostatic structures and stopbands in a three-component magnetosheath plasma

On a modified Korteweg–de Vries equation for electrostatic structures in relativistic degenerate electron–positron plasma

In this paper, the propagation of acoustic solitons in an electron–positron (e–p) degenerate plasma with the relativistically degenerate electrons and positrons is studied. Moreover, we considered stationary positive ions for neutralizing the plasma background. Using the reductive perturbation method, we obtained a modified Korteweg–de Vries equation. By applying a Jacobi elliptic function expansion method, we have proposed the exact analytical solitary, kink, and periodic solutions for the nonlinear wave structures. Also, using the phase plane analysis three equilibrium points have been perceived two of them should be centers and the last is a saddle for quantum acoustic waves. The numerical and computational results show that firstly some of them should be discarded by physical values and then these solutions have been influenced by the plasma parameters such as the electron degenerate density parameter (ne0) and the ion-to-electron density ratio (δ) which peaked out in white dwarf stars. It is found that both the amplitude and the width of the nonlinear structures are affected by the mentioned parameters. This investigation is useful for the relativistically degenerate plasma media in ultra-dense astrophysical environments (such as neutron stars, white dwarfs, etc.), inertia fusion science, experiments involving the interaction of laser and solid density plasma, and inertial confinement fusion in which the relativistic effects play a major role.

The Stochastic Structural Modulations in Collapsing Maccari’s Model Solitons

The two-dimensional Maccari nonlinear system performs the energy and wave dynamical features in fiber communications and modern physical science as hydrodynamic and space plasma. Several new forms of solutions for the Maccari’s model are constructed by a unified solver method that mainly depends on He’s variations method. The obtained solutions identify new wave stochastic structures with important features in energy physics such as rational explosive, breather, dispersive, explosive dissipated, dark solitons and blow-up (shock structure). It was elucidated that the random effects amend the energy wave strength or the collapsing due to model medium turbulence. Finally, the produced stochastic structures may be vital in some of these relationships between dispersions, nonlinearity and dissipative effects. The predominant energy waves that are collapsing or being forced may be applied to electrostatic auroral Langmuir structures and energy-generating ocean waves.

Quantitative and qualitative analyses of the mKdV equation and modeling nonlinear waves in plasma

In this paper, nonlinear electrostatic structures on the ion time scale in plasma consisting of two populations of electrons (cold and hot), positrons, and warm adiabatic ions are investigated. The multiple scale method is used to derive the modified Korteweg–de Vries equation (mKdVE). The Jacobi elliptic function expansion method (JEFEM) is employed to find some exact analytical solutions such as periodic, solitonic, and shock solutions. It is shown that the variation in the plasma parameters of interest, for our model, allows the existence of solitary and periodic structures and no shocks. It is also shown that the most important plasma parameters for the plasma model under consideration are positron concentration, α, and the percentage of cold and hot electrons, represented by the parameters μ and ν, respectively. Additionally, the qualitative behavior of the mKdVE is studied using dynamical system theory. The topological structure of the solution is discussed in the phase plane. In this work, the phase plane analysis, which is restricted to the discrete values of the parameter, is extended to the continuous range of the parameter using a bifurcation diagram. Bifurcation diagrams are drawn to forecast the behavior of the solution for specifically chosen essential plasma parameters. The analytical solution and the qualitative behavior of the solution presented in this paper are shown to be compatible with each other. The results presented here are general and can be gainfully employed to study a variety of nonlinear waves in space, laboratory plasmas, and astrophysical plasmas.

Dynamical energy effects in subsonic collapsing electrostatic Langmuir soliton

The nonlinear characteristic of subsonic Langmuir collapsing waves and energy has been explored using a mathematical system for plasma fluids. New electrostatic Langmuir structures such as supersolitary, breather dissipative, and supersoliton structures have been obtained via a mathematical robust solver. The obtained structures become important in constrained relation between the nonlinearity, dispersion, and dissipative effects in the model. It was discovered that the type of Langmuir structures controlled the collapsing energy for density turbulence. Breather shock forms in time are used to characterize the collapsing Langmuir dissipative waves. This structure mainly affects the electric field and related densities in the subsonic case. Finally, the results explored here may be applicable to the observation of energy collapsing Langmuir solar wind waves.

Existence and propagation characteristics of ion-acoustic Kadomtsev–Petviashvili (KP) solitons in nonthermal multi-ion plasmas with kappa distributed electrons

The dynamics of two dimensional Kadomtsev–Petviashvili (KP) electrostatic solitary waves (ESWs) propagating in multi-ion unmagnetized plasma is investigated, in the presence of energetic (nonthermal) electrons. Two distinct ion components are considered as inertial fluids, while inertialess electrons are characterized by an excess superthermal population described by a kappa distribution. The primary (heavier and cold) ion population is assumed to be positively charged, while the charge and sign of the (lighter and warm) ions is left arbitrary in the model. A linear analysis reveals the existence of two harmonic modes propagating with different phase speeds, identified as slow and fast ion-acoustic waves i.e., SIAW, FIAW respectively. Nonlinear analysis, based on a multiscale (reductive perturbation) technique, leads to a two-dimensional Kadomtsev–Petviashvili (KP) equation for the electrostatic potential. Pulse-shaped electrostatic potential solitary wave solutions and associated bipolar electric field structures are obtained analytically as well numerically. A parametric investigation reveals that, if both ion species are positively charged, then either negative or positive polarity electrostatic potential solitary waves structures may occur for the slow (SIAW) mode case (only), depending on the light ion density and temperature. On the other hand, considering a negatively charged light (warm) ion fluid case, then solitary structures of SIAW are formed of positive polarity (only), while their fast counterpart FIAW is of opposite (negative) polarity. The (O, H) multi-ion plasma is considered and parametric dependence of nonlinear electrostatic solitary wave characteristics (amplitude, width) on the intrinsic plasma configurational parameters i.e., light-to-heavy ion density and light ion to electron temperature ratios and nonthermal electrons spectral index kappa is investigated.

Electrostatic interactions, binding energies and structures of the [formula omitted] complexes

The binding energies and structures of the Be cations with H2 molecules are studied theoretically at the level of the MP2 method. In this study the aug-cc-pVTZ basis set is used to describe the electronic configuration of these atoms in the complex. The structures of these complexes are determined for Be+2·H21-4 complexes. The sequential bond energies of the Be2+·(H2)1−4 complexes are also examined. The variations in the electrostatic interaction energies could be the cause of the observed trend in sequential bond dissociation energy values.

Double Layers in the Earth's Bow Shock

AbstractWe present Magnetospheric Multiscale observations of electrostatic double layers in quasi‐perpendicular Earth's bow shock. These double layers have predominantly parallel electric field with amplitudes up to 100 mV/m, spatial widths of 50–700 m, and plasma frame speeds within 100 km/s. The potential drop across a single double layer is 2%–7% of the cross‐shock potential in the de Hoffmann‐Teller frame and occurs over the spatial scale of 10 Debye lengths or one tenth of electron inertial length. Some double layers can have spatial width of 70 Debye lengths and potential drop up to 30% of the cross‐shock potential. The electron temperature variation observed across double layers is roughly consistent with their potential drop. While electron heating in the Earth's bow shock occurs predominantly due to the quasi‐static electric field in the de Hoffmann‐Teller frame, these observations show that electron temperature can also increase across Debye‐scale electrostatic structures.