Plasma Electrodynamics Research Articles

Magnetospheric Control of Ionospheric TEC Perturbations via Whistler-Mode and ULF Waves.

The weakly ionized plasma in the Earth's ionosphere is controlled by a complex interplay between solar and magnetospheric inputs from above, atmospheric processes from below, and plasma electrodynamics from within. This interaction results in ionosphere structuring and variability that pose major challenges for accurate ionosphere prediction for global navigation satellite system (GNSS) related applications and space weather research. The ionospheric structuring and variability are often probed using the total electron content (TEC) and its relative perturbations (dTEC). Among dTEC variations observed at high latitudes, a unique modulation pattern has been linked to magnetospheric ultra-low-frequency (ULF) waves, yet its underlying mechanisms remain unclear. Here using magnetically conjugate observations from the THEMIS spacecraft and a ground-based GPS receiver at Fairbanks, Alaska, we provide direct evidence that these dTEC modulations are driven by magnetospheric electron precipitation induced by ULF-modulated whistler-mode waves. We observed peak-to-peak dTEC amplitudes reaching 0.5 TECU (1 TECU is equal to electrons/ ) with modulations spanning scales of 5-100km. The cross-correlation between our modeled and observed dTEC reached 0.8 during the conjugacy period but decreased outside of it. The spectra of whistler-mode waves and dTEC also matched closely at ULF frequencies during the conjugacy period but diverged outside of it. Our findings elucidate the high-latitude dTEC generation from magnetospheric wave-induced precipitation, addressing a significant gap in current physics-based dTEC modeling. Theses results thus improve ionospheric dTEC prediction and enhance our understanding of magnetosphere-ionosphere coupling via ULF waves.

Nonlinear waves for a variable-coefficient modified Kadomtsev–Petviashvili system in plasma physics and electrodynamics

In this paper, a variable-coefficient modified Kadomtsev–Petviashvili (vcmKP) system is investigated by modeling the propagation of electromagnetic waves in an isotropic charge-free infinite ferromagnetic thin film and nonlinear waves in plasma physics and electrodynamics. Painlevé analysis is given out, and an auto-Bäcklund transformation is constructed via the truncated Painlevé expansion. Based on the auto-Bäcklund transformation, analytic solutions are given, including the solitonic, periodic and rational solutions. Using the Lie symmetry approach, infinitesimal generators and symmetry groups are presented. With the Lagrangian, the vcmKP equation is shown to be nonlinearly self-adjoint. Moreover, conservation laws for the vcmKP equation are derived by means of a general conservation theorem. Besides, the physical characteristics of the influences of the coefficient parameters on the solutions are discussed graphically. Those solutions have comprehensive implications for the propagation of solitary waves in nonuniform backgrounds.

MK-200 Plasma Gun Facility

Plasma flows with high velocity, density, and energy are widely used in research on the interaction of plasma with materials, modeling of astrophysical processes, development of plasma thrusters and plasma radiation sources, and plasma injection into fusion devices. Electrodynamic plasma guns can be used to generate such flows. This paper describes the design features of a powerful pulsed plasma gun and diagnostic tools for measuring the parameters of the plasma flow generated by it.

Slipping instability of an inhomogeneous relativistic electron beam

The charged particle beams, such as electrons, ions, and plasma compression flow, have received considerable attention due to their applications in science and technology; therefore, studying the stability of these beams is of particular importance. Here, we examine theoretically the stability properties of a cold relativistic electron beam with a transverse velocity shear and non-uniform density profile. We consider a plane-parallel beam propagating along an external magnetic field and evaluate its macroscopic equilibrium state. We derive the dispersion relation of the slipping instability based on the linear electrodynamics of an inhomogeneous plasma and kinetic theory. In this model, the oscillation spectrum and the growth rate are derived by using the eikonal equation and the quasi-classical quantization rule. A linear velocity shear and a non-linear density gradient are assumed. Furthermore, we analyze numerically the dispersion relation of the slipping instability. The impacts of the inhomogeneity parameter and the relativistic factor on the properties of the slipping instability are discussed.

Потенциал Корнелла в столкновительной кварк-глюонной плазме

In experimental studies of quark-gluon plasma at accelerators, charmonium and bottomonium play an important role, since their onset of dissociation is one of the few signs of a phase transition in a hot and superdense medium. These particles represent the bound states of the heavy quark and antiquark of charm and bottom flavour, respectively. One of the well-studied research methods is considered to be phenomenological models, where the interaction between quarks is described by the Cornell-type potentials, as well as its modifications. This article examines the influence of the movement of charmonium and bottomonium in an environment on the potential, using dynamic screening. For screening, the dielectric function of the wake field has been used by analogy with the electrodynamics of an ordinary plasma, in view of the similarity of description, which is characteristic only for these bound states. This dielectric function has been obtained from a collisional plasma based on the Boltzmann equation with the Bhatnagar-Gross-Krook collision operator. As a consequence, the equation describes the medium as rarefied gas with pair collisions between particles. Effective potentials between quarks in a given medium are constructed using the method of random-phase approximation. Potentials were obtained as a function of the relative motion of bound states in the medium and the collision frequency of counterpropagating particles. The characteristic changes in the potential in the direction of particle motion are graphically shown, depending on the magnitude of these parameters.

Fine-structure of electromagnetic radiation reflected from the O–X mode conversion zone in magnetized plasma

The linear coupling between the ordinary and extraordinary waves in the vicinity of the plasma cutoff is used for the heating of overdense plasma in toroidal magnetic devices. If the mode coupling is not perfect, there is reflected ordinary wave radiation. In this paper, we analyze the structure of this radiation in a realistic case of an incident beam with a finite aperture. It is shown that reflection from the evanescent layer in inhomogeneous gyrotropic plasma results in wave distributions with a non-zero-angular momentum. A helicity of the reflected beam results in unusual effects, at least in the plasma electrodynamics, which are identified and discussed.

ICARUS: in-situ studies of the solar corona beyond Parker Solar Probe and Solar Orbiter

The primary scientific goal of ICARUS (Investigation of Coronal AcceleRation and heating of solar wind Up to the Sun), a mother-daughter satellite mission, proposed in response to the ESA “Voyage 2050” Call, will be to determine how the magnetic field and plasma dynamics in the outer solar atmosphere give rise to the corona, the solar wind, and the entire heliosphere. Reaching this goal will be a Rosetta Stone step, with results that are broadly applicable within the fields of space plasma physics and astrophysics. Within ESA’s Cosmic Vision roadmap, these science goals address Theme 2: “How does the Solar System work?” by investigating basic processes occurring “From the Sun to the edge of the Solar System”. ICARUS will not only advance our understanding of the plasma environment around our Sun, but also of the numerous magnetically active stars with hot plasma coronae. ICARUS I will perform the first direct in situ measurements of electromagnetic fields, particle acceleration, wave activity, energy distribution, and flows directly in the regions in which the solar wind emerges from the coronal plasma. ICARUS I will have a perihelion altitude of 1 solar radius and will cross the region where the major energy deposition occurs. The polar orbit of ICARUS I will enable crossing the regions where both the fast and slow winds are generated. It will probe the local characteristics of the plasma and provide unique information about the physical processes involved in the creation of the solar wind. ICARUS II will observe this region using remote-sensing instruments, providing simultaneous, contextual information about regions crossed by ICARUS I and the solar atmosphere below as observed by solar telescopes. It will thus provide bridges for understanding the magnetic links between the heliosphere and the solar atmosphere. Such information is crucial to our understanding of the plasma physics and electrodynamics of the solar atmosphere. ICARUS II will also play a very important relay role, enabling the radio-link with ICARUS I. It will receive, collect, and store information transmitted from ICARUS I during its closest approach to the Sun. It will also perform preliminary data processing before transmitting it to Earth. Performing such unique in situ observations in the area where presumably hazardous solar energetic particles are energized, ICARUS will provide fundamental advances in our capabilities to monitor and forecast the space radiation environment. Therefore, the results from the ICARUS mission will be extremely crucial for future space explorations, especially for long-term crewed space missions.

Electrodynamic Plasma Thruster with Capillary-Porous Electrode

Electrodynamic Plasma Thruster with Capillary-Porous Electrode

Polarized coherent microwave supercontinua with a terawatt laser driver

Ultrafast laser-plasma interactions driven by ultrashort terawatt laser pulses are shown to give rise to a bright multioctave microwave radiation, whose polarization and spatial mode structure provides a sensitive probe for laser-driven plasma electrodynamics, helping detect the symmetries of plasma currents and signatures of multiple ionization. Polarization mode structure of this radiation is dominated, as polarization-resolved measurements show, by a radially polarized mode, indicating the significance of ponderomotively driven plasma currents as sources of microwave emission. Angle-resolved analysis of microwave supercontinua reveals regimes in which the microwave emission is drastically enhanced, via coherence buildup, manifested in a well-resolved Cherenkov-emission cone.

On the spectra of natural waves in a plasma waveguide in the presence of collisions

The dispersion characteristics of surface and evanescent waves in metal-dielectric-plasma-dielectric-metal structure in the presence of collisions are investigated analytically and numer
 ically. In the absence of absorption, when the electron density passes through the doubled critical value, a rearrangement of the eigenwave structure, associated with the appearance of surface waves, occurs. A rearrangement also occurs in an absorbing plasma, but the numbers of reconnecting modes depend on the size of the structure and the ratio of the electron collision frequency to the field frequency. Correct consideration of this process is necessary for the analytical analysis of the field structure in plasma reactors, the design of plasma antennas, and the solution of other problems of plasma electrodynamics.

Miniaturized rotating magnetic field–driven plasma system: proof-of-concept experiments

The development of plasma-based propulsion thrusters for spacecraft has seen a rapid growth over the past few decades, with the number of spacecraft including small satellites and Cubesats increasing exponentially. Although traditional chemical propulsion is still widely employed in space flights, it cannot meet the more challenging requirements for deep space travel due to low specific impulse. Electric propulsion thrusters have already helped humans travel further from Earth and have the potential to be developed for interstellar flights due to their advantages such as high velocity increments, long operational lifetimes, high impulse-to-weight ratios and high impulse-to-power ratios. The electrodynamic thrusters have significant potential for applications in the remote regions of space, and several types of electrodynamic plasma thrusters are currently under investigation. In this paper we present conceptual experiments to study a miniaturized Rotamak-type device initially proposed for the controlled thermonuclear fusion, with a view to assess its potential for the application as a small space thruster. An outline of the physical characteristics of the experiments that has been carried out, and measurements were done to try to elucidate the important mechanisms at work in the Rotamak, which will help design next-generation thruster capabilities. A discussion is also presented about the Rotamak systems and the opportunities they present for space applications.

Proton-boron fusion in a compact scheme of plasma oscillatory confinement.

We present the results of experiments on the aneutronic fusion of proton-boron (pB) in a single miniature device with electrodynamic (oscillatory) plasma confinement. The device is based on a low energy (∼1-2J) nanosecond vacuum discharge with a virtual cathode, the field of which accelerates protons and boron ions to the energies required for pB synthesis (∼100-300keV) under oscillating ions' head-on collisions. The yields of α particles registered for different conditions of the experiment are presented and discussed in detail. The experiment was preceded by particle-in-cell modeling of main processes accompanying pB reaction within the framework of the full electromagnetic code karat. The summary yield of α particles of about 5×10^{4}/4π was obtained during the pulse-periodic operation of the generator within total 4μs of the high voltage applied, which is ∼10α particles/ns.

Thermalization of the plasma arising during counter collision of high-energy plasma flows in a longitudinal magnetic field

This work is devoted to the study of thermalization of plasma created by head-on collisions of high-energy plasma flows in a longitudinal magnetic field of 0.5–2 T. Hydrodynamic flows contained the energy of 200 kJ with velocities from 2 × 107 to 4 × 107 cm/s and ion density from 2 × 1015 to 4 × 1015 cm−3 were created inside the 2MK-200 facility by two electrodynamic plasma accelerators equipped by a system of pulsed gas injection. Nitrogen, neon and their mixtures with hydrogen and deuterium were implemented as working gases. A process of plasma creating was investigated by near-wall magnetic probes situated in different parts of the interaction chamber. Temporal evolution of the plasma electron temperature had been traced by x-ray photodiodes covered by different filters. It was discovered that the plasma electron temperature changed insignificantly during 6–8 μs after it reached the maximum value, which means that it ionization state can be considered as quasi-stationary.

The Cusp as a VLF Saucer Source: First Rocket Observations of Long‐Duration VLF Saucers on the Dayside

AbstractAuroral whistler‐mode radio emissions called saucers are of fundamental interest because they require an unusually stationary emission process in the dynamic auroral environment, and it is a mystery how that can happen in this or similar conditions elsewhere in geospace. The Cusp Alfvén and Plasma Electrodynamics Rocket (CAPER‐2), launched into the cusp, obtained the first rocket measurements of a large‐scale, multiple‐armed dayside saucer, similar to those observed by the DEMETER satellite, with the addition of particle measurements and ground‐based measurements. Analysis of saucer shapes, directional measurements using waveforms, and ground‐based data show that, accounting for estimated uncertainties, these originate at altitudes ∼4,000 km within the cusp, the eastern side of which is penetrated by the rocket ∼100 s after the saucers are encountered. On‐board particle instruments show dispersed electron bursts in the cusp, Alfvénically accelerated at altitudes at or above the saucer sources.

Чисельне моделювання нестаціонарних потоків холодної плазми при роботі плазмового актуатора

The numerical simulation of unsteady flows of cold plasma is considered in this article. A low-temperature non-equilibrium ideal plasma is formed when the plasma actuator interacts with the air. The mathematical model has been developed to describe the behavior of low-temperature plasma. It is based on non-stationary equations describing the dynamics of charged particles and plasma electrodynamics equations. The 14 types of particles: metastable and excited nitrogen and oxygen atoms, positive and negative ions, electrons and atomic oxygen are considered. Volumetric and surface chemical reactions describing processes in a barrier discharge that occur above the dielectric surface are considered. For non-stationary equations of plasma dynamics, an implicit numerical algorithm with pseudo-time iteration has been developed, which is based on a finite-volume approach. The equation for the electrostatic potential with sources was solved using the generalized minimal residual method with incomplete LU preconditioning. In non-stationary equations for the density of plasma particles, the drift derivatives were approximated using the TVD scheme with the MinMod limiter function. The derivatives in the equation for the electric potential were calculated using finite-volume relations taking into account the upwind approximation of the concentration of charged plasma particles. The numerical results of the generation, propagation and destruction of a streamer during a dielectric barrier discharge are obtained. The unsteady plasma characteristics in the region above the dielectric surface are analyzed, including the distribution of the particles density, electric potential and the Lorentz force components. The results of numerical simulation of unsteady flows of low-temperature plasma are in good agreement with the available experimental data.

Background field method in thermo field dynamics for wave propagation in unmagnetized spinor QED plasmas

In this paper, we propose a relativistic quantum many-body theory for the collective modes in spinor quantum electrodynamic plasma. Different from the usual quantization scheme, we use the self-consistency nontrivial background field method in the framework of thermo field dynamics, in which the resulting quanta are temperature-dependent particles instead of the observable ones such as electrons, positrons, and photons. The theory provides a general scheme for many-body physics, which overcomes the disadvantages of random phase, Hartree–Fock, or other equivalent mean-field approximations. The essential point for our theory is to exactly evaluate the background fields. In this paper, we propose a general and efficient method to determine them, which we name as the “classical limit method” for convenience. To demonstrate how to apply the theory, we discuss the collective modes in unmagnetized electron–positron plasma, in both the low-energy and high-energy limits. It yields the well-known dispersion relations of longitudinal and transverse modes for non-relativistic degenerate plasmas, at zero and nonzero temperature. Furthermore, it gives the additional relativistic and vacuum fluctuation corrections, including increasing mass, decreasing effective charge, finite light velocity influence on the dispersion relation, and virtual charge redistribution. The last effect is reported for the first time.

Laser-driven vacuum breakdown waves

It is demonstrated by three-dimensional quantum electrodynamics — particle-in-cell (QED-PIC) simulations that vacuum breakdown wave in the form of QED cascade front can propagate in an extremely intense plane electromagnetic wave. The result disproves the statement that the self-sustained cascading is not possible in a plane wave configuration. In the simulations the cascade is initiated during laser-foil interaction in the light sail regime. As a result, a constantly growing electron-positron plasma cushion is formed between the foil and laser radiation. The cushion plasma efficiently absorbs the laser energy and decouples the radiation from the moving foil thereby interrupting the ion acceleration. The models describing propagation of the cascade front and electrodynamics of the cushion plasma are presented and their predictions are in a qualitative agreement with the results of numerical simulations.

Causality in Plasma Electrodynamics

Causality in electrodynamics is reviewed in regard to the interrelations among the causal requirement, the analyticity of the dielectric permittivity, and the Kramers-Kronig relations. We show that the collisionless damping (Landau damping) of a plasma wave can be formally derived from the causal requirement imposed on the susceptibility of a Vlasov-Poisson plasma. Here, the causal requirement is that the susceptibility χ(t) be nil for t < 0, which means the future electric field has nothing to do with the response effected in the medium at the present time. We show that this single requirement provides the analyticity of χ(ω) in the upper half-ω plane, the Kramers- Kronig relations, and Landau damping. Cerenkov emission which is the inverse process of Landau damping is also discussed in the light of causality. We present an easy way to calculate the electric fluctuation in a magnetized plasma by regarding a plasma as an assembly of non-interacting cold beams. We investigate the case of a separable distribution function $$g(x,t,v) = \tilde g(v)f(x - {v_0}t)$$ , which corresponds to a special type of Benstein-Greene-Kruskal wave and a slight generalization of Van Kampen’s distribution function. We review Van Kampen’s theory of a Vlasov-Poisson system, which corresponds to the Sturm-Liouville theory of differential equations, and show that the Vlasov- Poisson equations in this separable case are trivially solved in terms of the separation constant. It is philosophically interesting that the collisionless damping of a plasma wave can be attributed to causality, which defines the direction of time and is operative in general electrodynamics.

OML evaluation of the dust grain charge under quasineutrality conditions

Interaction potentials of electrons and ions with dust particles are developed to consistently treat plasma electrodynamics. It is assumed for the sake for simplicity that the material, the dust particles are made of, is a perfect conductor, and, then, the linear density-response formalism in the random phase approximation is used to take into account finite dimensions of grains. Additionally, the number density of protons is kept fixed such that the negative electric charge is allocated between the free electrons and the dust particles to assure the whole quasineutrality of the system. On the ground of the developed interaction potentials the electric charge of the dust particles is then calculated within the orbital motion limited (OML) approximation, which stems from the ballistic trajectories of the plasma particles at the charging process. It is rather clear that to advocate such a technique the mean free paths of the plasma particles must be much greater than the dimension of the dust grain. It is well known that under OML assumptions the conservation laws of energy and angular momentum are sufficient to determine the absorption cross sections of electrons and ions by the dust particle. The resultant absorption cross sections are then integrated over the velocity distribution distribution function to evaluate the fluxes of plasma particles on the grain surface, and the electric charge of the dust particle is stabilized when those fluxes are finally equalized.

Time-nonlocal kinetic equations, jerk and hyperjerk in plasmas and solar physics

The simulation and analysis of nonlocal effects in fluids and plasmas is an inherently complicated problem due to the massive breadth of physics required to describe the nonlocal dynamics. This is a multi-physics problem that draws upon various miscellaneous fields, such as electromagnetism and statistical mechanics. In this paper we strive to focus on one narrow but motivating mathematical way: the derivation of nonlocal plasma-fluid equations from a generalized nonlocal Liouville derivative operator motivated from Suykens's nonlocal arguments. The paper aims to provide a guideline toward modeling nonlocal effects occurring in plasma-fluid systems by means of a generalized nonlocal Boltzmann equation. The generalized nonlocal equations of fluid dynamics are derived and their implications in plasma-fluid systems are addressed, discussed and analyzed. Three main topics were discussed: Landau damping in plasma electrodynamics, ideal MHD and solar wind. A number of features were revealed, analyzed and confronted with recent research results and observations.