Plasma Phenomena Research Articles

Rocket‐Released Neutral Clouds in the Ionosphere: Formation, Evolution, and Detection

AbstractReleasing diffuse artificial clouds into the space environment using a rocket or spacecraft can modify the natural plasma state. This uses space itself as a laboratory for studying plasma phenomena that cannot be reproduced on the ground. The Space Measurement of A Rocket‐released Turbulence (SMART) mission will inject a beam of barium neutral vapor into the ionosphere and perpendicular to the Earth's magnetic field. Barium atoms will be photoionized, forming an ion ring distribution that is unstable to lower hybrid waves. Large amplitude lower hybrid waves nonlinearly scatter to whistler and magnetosonic waves that can propagate out to the magnetosphere. This paper details the theory, modeling, and simulation we used to design this release experiment to optimize the energy in the plasma waves under a variety of constraints. A product of this analysis is quantitative predictions for some in situ and remote measurements. Hydrocode simulations of barium vapourization and acceleration via shaped charge provide the initial state of the neutral beam. We optimize the apogee, orientation, and position of the payload and instruments. Cloud dynamics are simulated with a direct simulation Monte Carlo technique, which includes photoionization with metastable barium states, collisions with the neutral background atmosphere, optical line emission, gravity, and electromagnetic forces. We predict the plasma density measured by the instrument payload and the remotely measured optical intensity. We also examine how the plasma wave growth differs at the measurement location compared to the bulk of the barium cloud.

Traveling wave solutions of generalized seventh-order time-fractional KdV models through He-Laplace algorithm

Non-linear evolution equations play a prominent role in describing a wide range of phenomena in optical fibers, fluid dynamics, electromagnetic radiation, plasma and solid state physics. An important category of non-linear evolution models that characterizes shallow wave phenomena are the Korteweg-de Vries (KdV) models. In this regard, time-fractional Korteweg-de Vries models of seventh order are the main focus of this research. A general KdV seventh-order equation is considered with different coefficients to form Lax, Kaup–Kuperschimdt and Sawada–Kotera–Ito KdV models. An efficient semi-analytical algorithm named as He-Laplace (HLM) is applied for the solution of these models. In this algorithm, Laplace transform is hybrid with homotopy perturbation method (HPM). This study provides important results as non-linear evolution seventh-order models in fractional sense have not been captured through HLM in current literature. Absolute errors are computed and compared with already existing results to confirm the superiority of proposed algorithm over other existing techniques. Numerical and graphical investigations are conducted to evaluate the approximate series form solutions. The dynamic behavior of fractional parameter is observed by calculating residual errors and plotting two dimensional diagrams throughout the fractional-domain. Analysis confirms that the proposed methodology provides an effective and convenient way for solving fractional KdV models.

Push and pull magnetic reconnection driven by intense laser interaction with double-coil capacitor target

Push and pull magnetic reconnection (MR) experiments using high-power laser irradiating a capacitor target with the plates connected by a pair of U-shaped coils are carried out. During the beginning (end) of the laser-target interaction that creates a hot plasma in the region, the rise (fall) stages of the coil currents generates expanding (contracting) magnetic fields that reconnect in the midplane between the coils, resulting in push (pull) MR. Proton radiography and proton ray-tracing simulation are used to track the evolution of the magnetic fields. The proton accumulation and void formation between the coils are related to the oppositely directed current-sheet currents during the push and pull MR stages. The directions of the plasma electron outflows during these two MR phases are obtained by monitoring the soft x-ray emission. Our results suggest that the double-coil capacitor target may be useful for laboratory modeling of fast MR and related phenomena in astrophysical plasmas.

Exploring the Solar Wind-Planetary Interaction at Mars: Implication for Magnetic Reconnection.

The Martian crustal magnetic anomalies present a varied, asymmetric obstacle to the imposing draped interplanetary magnetic field (IMF) and solar wind plasma. Magnetic reconnection, a ubiquitous plasma phenomenon responsible for transferring energy and changing magnetic field topology, has been observed throughout the Martian magnetosphere. More specifically, reconnection can occur as a result of the interaction between crustal fields and the IMF, however, the global implications and changes to the overall magnetospheric structure of Mars have yet to be fully understood. Here, we present an analysis to determine these global implications by investigating external conditions that favor reconnection with the underlying crustal anomalies at Mars. To do so, we plot a map of the crustal anomalies' strength and orientation compiled from magnetic field data collected throughout the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. Then, we create "shear maps" which calculate and plot the angle of shear between the crustal fields and a chosen external field orientation. From there we define a "shear index" to quantify the susceptibility of a region to undergo reconnection based on a given overlaid, external field orientation and the resulting shear map for that region. We demonstrate that the shear analysis technique augments analysis of local reconnection events and suggests southward IMF conditions should favor dayside magnetic reconnection on a more global scale at Mars.

Relativistic toroidal light solitons in plasma

In the laser–plasma interaction, relativistic soliton formation is an interesting nonlinear phenomenon and important light mode convection in plasmas. Here, it is shown by three-dimensional particle-in-cell simulations that relativistic toroidal solitons, composed of intense light self-consistently trapped in toroidal plasma cavities, can be produced by azimuthally-polarized relativistic laser pulses in a near-critical underdense plasma.

Equilibrium selection via current sheet relaxation and guide field amplification

Although there is a continuous spectrum of current sheet equilibria, how a particular equilibrium is selected by a given system remains a mystery. Yet, only a limited number of equilibrium solutions are used for analyses of magnetized plasma phenomena. Here we present the exact process of equilibrium selection, by analyzing the relaxation process of a disequilibrated current sheet under a finite guide field. It is shown via phase-space analyses and particle-in-cell simulations that the current sheet relaxes in such a way that the guide field is locally amplified, yielding a mixed equilibrium from the spectrum. Comparisons to spacecraft observations and solar wind current sheet statistics demonstrate that such mixed equilibria are ubiquitous and exist as underlying local structures in various physical environments.

INVESTIGATION OF THE ELABORATE DYNAMICS OF WEAKLY NONLINEAR FRACTIONAL ION-ACOUSTIC WAVES IN MAGNETIZED ELECTRON–POSITRON PLASMA

This study employs three advanced computational and numerical techniques to solve the nonlinear fractional modified Korteweg–de Vries–Zakharov–Kuznetsov (mKdV–ZK) equation in magnetized plasma. The reductive perturbation approach is utilized to investigate the dynamics of various components, namely isothermal species, immobile background species, and warm adiabatic fluid, in magnetized plasma. Emphasis is placed on unraveling the asymmetrical propagation characteristics of nonlinear electrostatic waves. The model’s solutions encompass diverse types of solitons, including ion-acoustic, dust acoustic, and electron acoustic solitons. Analytical solutions are obtained using a variety of mathematical functions, such as exponents, trigonometry, and hyperbolas. Two- and three-dimensional density graphs illustrate the practical behavior of a single soliton. The primary objective of employing numerical schemes is to assess the accuracy of the derived solutions, and the outcomes demonstrate the efficacy of the analytical method in solving nonlinear mathematical and physical problems. Several techniques are employed to validate the consistency between calculated and estimated results, ensuring the study’s accuracy and reliability. Overall, this investigation underscores the effectiveness of numerical and analytical techniques in tackling complex mathematical models, offering a promising avenue for future research in the field. The findings carry significant implications for comprehending nonlinear phenomena in magnetized plasma and contribute to advancing the field.

The Association Between Atherogenic Index of Plasma and No-Reflow Phenomenon in Acute Coronary Syndrome.

The atherogenic index of plasma (AIP) is a biomarker of plasma atherogenicity. Elevated AIP is linked with adverse cardiac events. We sought to examine the association of admission AIP and no-reflow phenomenon (NRP) in acute coronary syndrome (ACS) patient population treated with percutaneous coronary intervention (PCI). Eight hundred eight-four ACS patients were included to statistical tests retrospectively and classified according to the occurrence of NRP: NRP (-) (n = 662) and NRP (+) (n = 186). AIP levels were calculated through the formula log10 (triglyceride-to-high-density lipoprotein cholesterol ratio). AIP levels were higher in NRP (+) patients compared to NRP (-) group patients. The receiver operating characteristic (ROC) curve analysis for AIP to predict NRP yielded an area under the ROC curve value 0.643 [95% confidence interval (CI): 0.596-0.690, P <.001]. AIP was associated with NRP in univariate logistic regression analysis [Odds Ratio (OR): 2.46; P =.001; CI: 1.44 (lower limit)-4.21 (upper limit)]. However, AIP did not emerge as a significant prognostic factor of NRP in multiple logistic regression analysis [OR: 2.11; P =.422; CI: 0.34 (lower limit)-13.11 (upper limit)]. On the other hand, peak troponin T (log10) was an independent prognostic factor for NRP [OR: 0.13; P <.001; CI: 0.10 (lower limit)-0.37 (upper limit)] occurrence. The AIP level on admission is not a statistically significant prognostic factor of NRP. However, peak troponin T (log10) is an independent prognostic parameter of NRP.

Cross section sets and transport parameters for Ar+ ions in CF4 gas

Understanding plasma distribution, characteristics and phenomena is important for the development and optimization of semiconductor device manufacturing plasma equipment, such as etching and deposition tools. For this reason, plasma simulation is currently being utilized at every stage of equipment design, development and improvement. The cross section sets obtained by applying Denpoh-Nanbu theory to Ar+ on CF4 collisions were found to be in general qualitative and in part quantitative agreement with data from the literature. The Monte Carlo technique was applied to perform calculations of transport parameters. Calculated cross sections can be used to obtain transport coefficients, specially drift velocity, characteristic energy, reduced mobility, longitudinal diffusion and rate coefficients for low and moderate reduced electric fields E/N (E-electric field strength; N-gas density) and accounting for the non-conservative collisions.

Measurements of ion fluxes in extreme ultraviolet-induced plasma of new EUV-beam-line 2 nanolithography research machine and their applications for optical component tests

In modern extreme ultraviolet (EUV) lithography machines, sensitive optical components, such as multilayer mirrors and photomasks, may be affected by plasma interactions. The new 13.5 nm EUV-beam-line 2, designed to provide accelerated tests for next generation lithography, is used to investigate EUV-induced plasma phenomena. First systematic measurements of ion fluxes produced in EUV-induced hydrogen plasma are reported, with operating conditions including 5 and 20 Pa gas pressure, 3 kHz EUV pulse repetition rate, and 4.2 W total EUV beam power produced in a 10–15 ns EUV pulse. Space- and time-resolved distributions of ion fluxes and ion energies were measured using a retarding-field ion energy analyzer mounted next to the EUV beam. Typical ion energies were in the range of 1–8 eV and typical ion fluxes were in the range of 2–8 × 1017 ions m−2 s−1. The obtained ion fluxes are applied in a photomask lifetime test to understand the material effects after an EUV exposure.

Collision rates estimated from exact N-body simulations of a one-dimensional plasma

In a plasma, the charged particles interact via long-range forces, and this interaction causes the plasma to exhibit collective effects. If the graininess or coupling parameter g goes to zero (ideal collisionless plasma), two-body collisions are negligible, while collective effects dominate the dynamics. In contrast, when g≈1 collisions play a significant role. To study the transition between a collisionless and a collisional regime, a N-body code was developed and used in this work. The code solves exactly, in one spatial dimension, the dynamics of N infinite parallel plane sheets for both ion and electron populations. We illustrate the transition between individual and collective effects by studying two basic plasma phenomena, the two-stream instability and Langmuir waves, for different values of g. The numerical collision rates given by the N-body code increase linearly with g for both phenomena, although with proportionality factors that differ by roughly a factor of two, a discrepancy that may be accounted for by the different initial conditions. All in all, the usual collision rates published in the literature (Spitzer collisionality) appear to compare rather well with the rates observed in our simulations.

A Data-Assimilation Based Method for Equilibrium Reconstruction of Magnetic Fusion Plasma: Solution by Adjoint Method

Accurately determining the magnetohydrodynamic (MHD) equilibrium is fundamentally important in controlling and stabilizing fusion plasmas. Development of reliable methods for equilibrium reconstruction is therefore crucial to advancing the fusion plasma research. However, since the dynamics of plasma phenomena are highly nonlinear and highly complicated dynamics, it is difficult to develop their rigorous mathematical model. We already proposed a method of equilibrium reconstruction for fusion plasmas based on data assimilation. In the method the problem is formulated as a parameter optimization and a solution by the sensitivity equation method is proposed. In this paper, we propose a solution of equilibrium reconstruction for fusion plasmas by the adjoint method for the purpose of reducing computation time. In order to ensure the applicability of the adjoint method to a wide class of fusion plasmas, the problem formulation and derivation of the reconstruction algorithm based on the adjoint method are performed in generic form. Furthermore, we implement the proposed method as equilibrium reconstruction algorithms applicable to axisymmetric toroidal plasmas, typical examples of which are tokamaks and reversed field pinches (RFPs). Finally, the proposed method is applied to a real RFP experiment, and it is shown that the proposed method has the capability of reconstructing the equilibrium with sufficient accuracy and dramatic reduction of computation time compared with the existing methods.

Fascinating physics at the edge of magnetic fusion devices

The physics of the processes at the edge of magnetic fusion devices is multifaceted and exhibits complex, nonlinear synergistic effects. Even though this region occupies only a small portion of the whole device, it plays a crucial role in overall plasma confinement, heat exhaust, and plasma–wall interactions. The latter affects not only the performance but also the lifetime of plasma-facing components and therefore remains an outstanding challenge for future fusion reactors. At the edge of fusion devices, researchers are dealing with phenomena including classical and anomalous plasma transport, atomic physics effects, and physics of plasma-facing material under strong irradiation by particle and energy fluxes. The diversity of edge physics makes it particularly attractive for young scientists. Working in this field, they can find endless possibilities to demonstrate their talents and creativity. This short review describes just some of the basic scrape-off layer and divertor plasma phenomena including divertor plasma detachment, intermittent bursts of anomalous cross-field plasma transport, plasma–material interactions, and dust in fusion plasmas, which are of particular interest in relation to fusion reactors.

Effects of ion to electron temperatures on electrostatic solitons with applications to space plasma environments

Electrostatic solitary waves (ESW) and solitons are widely observed nonlinear plasma phenomena in various space environments, which may be generated by the electron streaming instability as shown in many particle simulations. The predicted electron holes associated with the ESW, however, are not observed by the recent high resolution spacecraft. This raises a possibility for the ion acoustic solitons being the potential candidate, which are described by the Sagdeev potential theory with hot electrons and cold ions being treated by the kinetic equilibrium and fluid models, respectively. The assumption of Ti/Te=0 adopted in the theoretical models for ion acoustic solitons, however, imposes a great constraint for the space applications considering that Ti/Te may vary in a wide range of 0.1–10 in the Earth's space environments. This paper examines the effect of Ti/Te on ion acoustic solitons by including a finite temperature in the fluid equations for the ions, which, however, can no longer be solved based on the standard Sagdeev potential method. It is shown based on the nonlinear theory that larger Ti/Te may result in larger propagation speeds and the critical flow velocity for the existence of steady solitons increases with increasing Ti/Te values. The nonlinear solutions for various Ti/Te values may be characterized by an effective Mach number. For Ti/Te ≫ 1 the hot ions and cold electrons shall be described by the kinetic and fluid models, respectively, which may result in negative electric potentials opposite to the standard ion acoustic solitons. Comparisons between the model calculations and observations are made.

Nonlinear spectral analysis of ion acoustic solitons arising from a streaming charged object using the numerical inverse scattering transform

Observations of nonlinear coherent plasma phenomena in spacecraft and terrestrial experiments often rely on visual identification of solitary modes because nonlinear coherent modes are broadband in a Fourier transform based analysis. We implement an alternative spectral decomposition known as the inverse scattering transform and demonstrate its ability to successfully isolate nonlinear modes on the homogeneous and forced Korteweg–De Vries equation which models these nonlinear modes. We also demonstrate for the first time that this decomposition is useful when forcing is applied. This is because the stable modes generated by localized forcing are similar to the homogeneous solutions where the inverse scattering transform is a rigorous decomposition. This spectral technique is then applied to simulations of ion acoustic waves generated by a 10 mm spherical debris object interacting with the ionospheric plasma orbiting at 2000 km altitude. The algorithm is found to successfully detect the resultant solitons. This demonstrates the feasibility of using this spectral technique as a real time analysis tool for screening spacecraft data for nonlinear solitary modes.

Resolving multi-dimensional plasma phenomena in Hall thrusters using the reduced-order particle-in-cell scheme

Plasma in Hall thrusters exhibits a complex behavior, characterized by the interplay between various dominant processes in each of the thruster’s coordinates. The emergence of high-power Hall thrusters in the recent years and the design modifications intended to extend the lifetime of these devices have further amplified the three-dimensional nature of the plasma behavior. In this regard, the novel reduced-order particle-in-cell (PIC) scheme provides the possibility to resolve the multi-dimensional interactions in a Hall thruster at a computational cost up to two orders of magnitude lower than current multi-dimensional PIC simulations. To demonstrate this point, we present in this article the results from a series of pseudo-two-dimensional simulations we performed in three configurations: axial-azimuthal, azimuthal-radial, and axial-radial. We show that, in each configuration, the pseudo-2D PIC scheme provides a significantly improved picture of the involved physics compared to a one-dimensional PIC simulation and captures self-consistently the coupling between the plasma processes in different directions, notably similar to the observations from full-2D kinetic simulations.

О возможности использования данных геостационарного детектора молний для исследования плазменных явлений

The article deals with scientific and technical problems associated with the functionality of the geostationary lightning mapper, which is currently used for meteorological monitoring. Results of the study into the Schumann resonance phenomenon and the technical parameters of the mapper were analyzed simultaneously. A hypothesis is offered which suggests that there are pulsations in the time dependences of the radiation power of lightning activity at frequencies corresponding to Schumann resonance. A new application of the geostationary lightning mapper for studying plasma phenomena is proposed. Adding to the mapper an acousto-optic filter and a camera, which has the functions of switching the resolution/frame rate parameters, is shown to be useful for both meteorological and plasma studies.

Possibility of using GLM data for studying plasma phenomena

The article deals with scientific and technical problems associated with the functionality of the geostationary lightning mapper, which is currently used for meteorological monitoring. Results of the study into the Schumann resonance phenomenon and the technical parameters of the mapper were analyzed simultaneously. A hypothesis is offered which suggests that there are pulsations in the time dependences of the radiation power of lightning activity at frequencies corresponding to Schumann resonance. A new application of the geostationary lightning mapper for studying plasma phenomena is proposed. Adding to the mapper an acousto-optic filter and a camera, which has the functions of switching the resolution/frame rate parameters, is shown to be useful for both meteorological and plasma studies.

Data-driven discovery of reduced plasma physics models from fully kinetic simulations

At the core of some of the most important problems in plasma physics---from controlled nuclear fusion to the acceleration of cosmic rays---is the challenge to describe nonlinear, multiscale plasma dynamics. The development of reduced plasma models that balance between accuracy and complexity is critical to advancing theoretical comprehension and enabling holistic computational descriptions of these problems. Here we report the data-driven discovery of accurate reduced plasma models, in the form of partial differential equations, directly from first-principles particle-in-cell simulations. We achieve this by using an integral formulation of sparsity-based model-discovery techniques and show that this is crucial to robustly identify the governing equations in the presence of discrete particle noise. We demonstrate the potential of this approach by recovering the fundamental hierarchy of plasma physics models---from the Vlasov equation to magnetohydrodynamics. Our findings show that this data-driven methodology offers a promising route to accelerate the development of reduced theoretical models of complex nonlinear plasma phenomena and to design computationally efficient algorithms for multiscale plasma simulations.

The role of platelet microvesicles in the pathogenesis of preeclampsia

Among the diverse picture of preeclampsia, the hematological component, thrombocytopenia, attracts attention. Platelets are able to form microvesicles by budding the plasma membrane from the cell surface during apoptosis, stimulation, and also in a small amount in normal conditions. The membrane of these particles has a negative charge and contains phospholipids and an integral glycoprotein on the outer monolayer, due to which platelet microvesicles are involved in the process of blood coagulation and angiogenesis. Microvesicles are of platelet origin, they were first discovered in the middle of the last century in England when describing the phenomenon of plasma and serum coagulation in the absence of platelets in them. The number of platelet microvesicles dynamically changes during the formation of preeclampsia in pregnant women and in women with risk factors for the development of preeclampsia, which include obesity, arterial hypertension, diabetes mellitus, antiphospholipid syndrome. Exposure to these risk factors for preeclampsia before pregnancy leads to a change in the concentration of cells that produce microvesicles, which in turn can create conditions favorable for the development of preeclampsia during pregnancy. A special risk group are women with a history of preeclampsia. Taking into account the direct role of microvesicles in the processes of angiogenesis and blood coagulation, the study of these particles will allow a more detailed study of the pathophysiological aspects of the preeclampsia development, which will expand the possibilities for early prediction of this pathology and improvement of perinatal outcomes.