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We develop an analytical model for estimating the equilibrium quantities, such as electron temperature and number density, in an electron beam–plasma interaction system. This model provides a convenient way to calculate the effective electron temperature and density by considering the energy balance of the bulk cold electrons. Six energy sources/losses terms relevant to the cold electrons are accounted for, where quasi-linear theory is applied for estimating wave heating at equilibrium. We compare this calculation with the particle-in-cell (PIC) simulation results and find good agreement. Based on these results, we then consider two situations where we can simplify our model. The first is dominated by the balance between electron–electron Coulomb collisions and loss to the anode, which is mostly relevant to the conduction phase of plasma switches. The second is dominated by wave heating balanced by the anode loss, relevant to the electron beam–plasma discharge systems. We then couple our simplified energy balance model with the ion diffusion model and solve both the number density and the electron temperature as functions of the current density, electrode distance, pressure, and applied voltage, where a nice agreement is also obtained when comparing to PIC simulations. [ABSTRACT FROM AUTHOR]

We present experimental measurements of the electron temperature and density profiles and analyze the dynamics of a plasma bullet at volumetric concentrations of nitrogen admixture, 0%–3%, in an atmospheric-pressure nanosecond-pulsed argon jet plasma. Time-resolved Thomson scattering measurements taken 2.5 mm from the exit plane reveal that the temporal maximum of electron temperature and density reduced by as much as 55% and 29%, respectively, when mixing only 3% nitrogen to pure argon. These trends were consistent across axial locations from 2.5 to 14 mm from the exit plane for both electron temperature and density at nitrogen admixture plasmas. Moreover, the propagation velocity and length of the plasma bullet decreased by 13% while the radius by 23% at 3%-nitrogen admixture when compared to the pure argon jet case. The analysis suggests that the nitrogen admixture causes electron cooling due to inelastic energy losses, which results in a reduced electron density and propagation velocity due to a decrease in the electron-impact ionization rate. It is therefore inferred that the electron cooling mechanism and reduced density at nitrogen admixture will significantly impact the electron-impact excitation rate coefficient of nitrogen as well as the concentration of the precursor species such as N2(A3Σu+). [ABSTRACT FROM AUTHOR]

Screened plasmon properties of graphene near a perfect electric conductor (PEC) are investigated taking into account the retardation effects. A detailed discussion of the dispersion relation of the mentioned screened plasmonic waves is presented and illustrated graphically using classical electrodynamics and a linearized hydrodynamic model that includes Fermi correction. The result indicates that for realistic wavenumbers, the dispersion relation of plasmonic waves of isolated graphene is almost unaffected by the Fermi correction, while this correction is an important factor for the screened plasmons of graphene near a PEC, where it increases the frequency of surface waves. The results show that near the graphene neutrality point, the surface wave has linear dispersion with a universal speed close to v F / 2. Such linear dispersion for surface waves (also known as energy waves) appears to be a common occurrence when splitting of plasma frequencies occurs, e.g., in the electron–hole plasma of graphene [Zhao et al., Nature 614, 688 (2023)]. Furthermore, analytical expressions for the energy parameters (the power flow, energy density, and energy velocity) of screened plasmons of the system are derived. Also, the analytical expressions are derived and analyzed for the damping function and surface plasmon and electromagnetic field strength functions of surface waves of the system with small intrinsic damping. [ABSTRACT FROM AUTHOR]

A model for fast electron-driven high-density plasma is proposed to describe the effect of injected fast electrons on the temperature and inner pressure of the plasma in the fast heating process of the double-cone ignition (DCI) scheme. Due to the collision of the two low-density plasmas, the density and volume of the high-density plasma vary. Therefore, the ignition temperature and energy requirement of the high-density plasma vary at different moments, and the required energy for hot electrons to heat the plasma also changes. In practical experiments, the energy input of hot electrons needs to be considered. To reduce the energy input of hot electrons, the optimal moment and the shortest time for injecting hot electrons with minimum energy are analyzed. In this paper, it is proposed to inject hot electrons for a short time to heat the high-density plasma to a relatively high temperature. Then, the alpha particles with the high heating rate and P d V work heat the plasma to the ignition temperature, further reducing the energy required to inject hot electrons. The study of the injection time of fast electrons can reduce the energy requirement of fast electrons for the high-density plasma and increase the probability of successful ignition of the high-density plasma. [ABSTRACT FROM AUTHOR]

Electron firehose instabilities can be excited at dipolarization fronts and in the magnetic reconnection outflow in the terrestrial magnetotail, but their occurrence rate in the plasma sheet is unclear. Here, we investigate the characteristics of electron firehose unstable conditions in the magnetotail plasma sheet based on observations of the Magnetospheric Multiscale mission. We find an Alfvénic magnetic field fluctuation accompanied by a strong field-aligned current during a flapping motion. This fluctuation occurs where the local plasma is electron firehose unstable, indicating that the electron firehose instability in the plasma sheet can occur in the region besides dipolarization fronts and magnetic reconnection outflow. We statistically find that the local plasma near the neutral sheet has a small probability with the maximum value <1.4% to be electron firehose unstable, which mainly occurs in the central plasma sheet with BXY/BL < 0.3. The maximum probability of Tef > 0 (electron firehose unstable condition) is ∼1.36% (1.32%) at BXY/BL ≈ 0.05 (0.15) during fast (non-fast) flows. During fast flows, the plasma near the neutral sheet tends to have a higher probability of Tef > 0 when the local VT is larger. During non-fast flows, the plasma near the neutral sheet tends to have a higher probability of Tef > 0 when Te is larger. The probability of Tef > 0 shows a dawn-dusk asymmetry during fast flows and non-fast flows. In addition, the probability of Tef > 0 during fast flows tends to be larger when the ambient BZ is weak, which shows opposite characteristics during non-fast flows. These findings help to assess the importance of the role of electron firehose instabilities in the magnetotail plasma sheet. [ABSTRACT FROM AUTHOR]

The impact of spatial and temporal evolution of nonlinear mixing of two Gaussian laser pulses propagating in plasma on generation of terahertz (THz) radiation have been investigated taking into account the ponderomotive nonlinearity. By calculating the modified electron density of plasma caused by the finite ponderomotive force of the pump lasers and using wave equation and paraxial ray approximation, two coupled governing equations for temporal and spatial pulse‐width parameters have been derived. The electric field of the THz wave as a result of nonlinear current density induced by the beat ponderomotive force of the pulses was extracted. Combined effects of initial laser and plasma parameters on the behavior of self‐compression and self‐focusing as well as THz radiation generation were investigated. The numerical results indicated a considerable spatiotemporal compression takes place within a specific range of laser intensity, exhibiting a saturation intensity point where the compression process reaches its maximum extent. It is observed that the generated THz radiation also strongly depends on the spatiotemporal dynamics of the pump pulses. The maximum THz amplitude corresponds to the strongest pump pulse compression extent. [ABSTRACT FROM AUTHOR]

A discharge in the annular cavity of a Hall effect thruster is sustained by extracting electrons from a radiofrequency (rf) inductively coupled plasma source located downstream of the thruster structure, where a radial magnetic field of 0.1-0.15 T is applied to the thruster discharge cavity by permanent magnets. Argon gas is introduced into the cavity via an anode structure and the ejected gas passes through the rf plasma source powered by a 13.56 MHz and 200 W generator. After turning on the rf plasma, a dc voltage is applied between a cathode installed inside the rf source and the anode of the Hall effect thruster, creating the bright annular discharge in the cavity. Measured ion energy distribution functions contain the energetic ions having the maximum potential close to the anode potential, demonstrating the ion acceleration from the annular cavity and the neutralization by the electrons in the rf plasma source. [ABSTRACT FROM AUTHOR]

We have measured several 2 p → 1 s transition energies in core-excited boron-like ions of sulfur and argon. The measurements are reference-free, with an accuracy of a few parts per million. The x-rays were produced by the plasma of an electron cyclotron resonance ion source and measured with a double-crystal x-ray spectrometer. The precision obtained for the measured 1 s 2 s 2 2 p 2 J - 1 s 2 2 s 2 2 p J ′ lines is ≈ 3.8 ppm for sulfur and ≈ 2.5 ppm for argon. The line energies are compared to relativistic atomic structure calculations performed with the mdfgme multi-configuration Dirac–Fock code. This comparison is used for line identification and tests the theoretical methods, which are in agreement with the experimental data up to 49 meV . The theoretical calculations have been extended to B, C + , Si 9 + , Cr 19 + and Fe 21 + , which were the only B-like ions where such transitions were measured up to now. [ABSTRACT FROM AUTHOR]

Since a theory that can justify the condition of matching of the laser and plasma parameters to implement the relativistic self-trapping regime for laser light in a plasma, which is the most efficient for the acceleration of electrons, is still absent, doubts remain in the necessity of the corresponding extensive experimental studies, particularly in view of the lack of justification or completion of previous theories. The presented theoretical analytical approach, which includes the relativistic nonlinearity of the electron mass and electron cavitation in the plasma, allows one to overcome this problem and provides an analytical justification of the conditions of such matching for ultrarelativistic laser beams at the quantitative level, which is in agreement with the multidimensional numerical simulation. [ABSTRACT FROM AUTHOR]

A novel Thomson-scattering diagnostic with continuous angular resolution over a span of 120° was developed for the characterization of plasmas produced at the Omega Laser Facility. Spectrally resolving light scattered from electron plasma wave features as a function of emission angle provides a means to efficiently probe a large range of plasma frequencies and k vectors. Together, these spectra contain critical constraints on the plasma-physics models used to interpret the data and enable experimental measurements of the electron-velocity distribution function over several orders of magnitude without assumptions about its mathematical form. Major components of the instrument include (1) a reflective collection objective that gathers light over a range of 120° × 12°; (2) a spatial-filter image relay for measurement localization; (3) cylindrical optics for producing a line image of the collection aperture; (4) a transmission grating spectrometer; and (5) a time-gated, image-intensified camera. Thomson-scattered light collected from an ∼ 50 − μ m 3 volume of plasma is recorded with 0.8-nm spectral and 1° angular resolution. Initial experiments examined the properties of the electron-velocity distribution in gas-jet-produced plasmas in the presence of heating via inverse bremsstrahlung absorption. [ABSTRACT FROM AUTHOR]

Spatiotemporal evolution of large amplitude upper-hybrid oscillations in a cold homogeneous plasma in the presence of an inhomogeneous magnetic field is studied analytically and numerically using the Dawson sheet model [J. Dawson, Phys. Fluids 5, 445–459 (1962)]. It is observed that the inhomogeneity in magnetic field, which causes the upper-hybrid frequency to acquire a spatial dependence, results in phase mixing and subsequent breaking of the upper-hybrid oscillations at arbitrarily low amplitudes. This result is in sharp contrast to the usual upper-hybrid oscillations in a homogeneous magnetic field, where the oscillations break within a fraction of a period when the amplitude exceeds a certain critical value [R. C. Davidson, Methods in Nonlinear Plasma Theory (Academic, New York, 1972)]. Our perturbative calculations show that the phase mixing (wave breaking) time scales inversely with the amplitude of magnetic field inhomogeneity (Δ) and amplitude of imposed density perturbation (δ) and scales directly with the ratio of magnetic field inhomogeneity scale length to imposed density perturbation scale length [ (α / k L) − 1 ] as ω p e τ mix ∼ (1 + β 2) 3 / 2 k L / (β 2 δ Δ α) , where β is the ratio of electron cyclotron frequency to electron plasma frequency. Further phase mixing time measured in simulations, performed using a 1–1/2 D code based on the Dawson sheet model [J. Dawson, Phys. Fluids 5, 445–459 (1962)], shows good agreement with the above-mentioned scaling. This result may be of relevance to plasma based particle acceleration experiments in the presence of a transverse inhomogeneous magnetic field. [ABSTRACT FROM AUTHOR]

Observation of a dip in plasma density with the rise of ion plasma waves demonstrates the process of detrapping electrons under the double-layer conditions in a DC glow discharge plasma. This study presents an experimental observation of self-excitation and interplay between electron and ion plasma waves when a high positive DC voltage ( V p ∼ + 100 V) is applied to a planar probe immersed in plasma. For lower voltages ( V p ∼ + 5 V), the electron sheath forms on the surface of the probe; however, for sufficiently high applied voltage, plasma could not supply the sufficient number of electrons to shield it from penetrating deep into the plasma. Therefore, the electron-deficient sheath attracts plasma electrons toward the probe, resulting in the excitation of plasma waves and the formation of double layers. Low energy streaming electrons get trapped in the double layers potential step. On ionization of background neutrals, trapped electrons get detrapped. It results in the excitation of ion waves and damping of electron plasma waves. The wavelet analysis of the observed floating potential fluctuations exhibits the interplay between electron and ion plasma waves. The trapping of electrons causes the excitation of electron plasma waves, and detrapping results in the excitation of ion plasma waves as overall electron density dips. It provides new insight into the nonlinear effects of the wave–wave interaction, the onset of Buneman instability, and streaming instability under the double-layer condition. [ABSTRACT FROM AUTHOR]

Head-on collision of the two small-amplitude electron-acoustic (EA) solitons is studied in an unmagnetized collisionless plasma in the presence of superthermal (hot) trapped electrons. For this purpose, using a well-known extended Poincare–Lighthill–Kuo (PLK) method, a pair of the trapped Korteweg–de Vries (tKdV) equations is derived to investigate the soliton trajectories and phase shifts. The latter are found dependent on amplitudes of the interacting solitons, effectively altering with hot-electron superthermality and plasma parameters. Typical parameters for the electron diffusion region (EDR) and day-side auroral zone have been selected to examine the impact of hot-electron superthermality, trapping parameter, hot-to-cold electron number density ratio, and cold-to-hot electron temperature ratio on the profiles of potential excitations and phase shifts of interacting solitons. It is found that phase speed of the EA waves becomes altered by varying the κ – parameter, strongly modifying the nonlinearity and dispersive coefficients in a superthermal trapped plasma. However, particle trapping phenomenon does not affect the linear phase speed but introduces a fractional nonlinearity in the tKdV equations of two interacting solitons. The impact of the adiabatic and isothermal pressures is also highlighted to show new modifications in the propagation characteristics of two interacting solitons. [ABSTRACT FROM AUTHOR]

In the present theoretical analysis, a new scheme of terahertz (THz) generation is proposed by beating of the two dark hollow laser beams (DHLBs) in the magnetized plasma under the influence of a D.C. electric field. The D.C. electric and static magnetic fields are applied mutually perpendicular to each other as well as to the direction of propagation of DHLBs. The nonlinear current density becomes strong due to the coupling between the nonlinear density and D.C. drift velocity of the electrons of magnetized plasma which is further responsible for THz generation. The normalized THz amplitude shows enhancement with the increase of D.C. electric and static magnetic fields. The dark-size parameter and beam order also play a significant role in the enhancement of the THz generation. The present scheme is capable of generating THz radiation at laser intensities 10 14 W / cm 2 , the magnetic field 38 kG , D.C. electric field 45 kV / cm , and electron temperature 6 keV. We have also considered the mutual interactions between the DHLBs and emitted THz radiation with magnetized plasma to provide more practical and accurate results. This scheme can be proved to be very effective and helpful in developing a proper tunable THz source for the investigation of histopathological samples, Bessel cell carcinoma tissues, and the treatment of tumors. [ABSTRACT FROM AUTHOR]

A thorough understanding of nuclear reaction rates at low energies is essential for improving our understanding of energy generation in stars and primordial and stellar nucleosynthesis. At low energies, fusion reactions between charged particles are strongly suppressed by the presence of the Coulomb barrier, which classically inhibits the penetration of one nucleus into another. The barrier penetration causes the cross section to have a steep energy dependence at low energies, making cross section measurements very challenging. Furthermore, little is known about the impact of surrounding electrons in stellar plasmas that are currently beyond the reach of experiments. As a result, measuring the bare cross sections as accurately as possible is essential. Reaction rate measurements at very low energies have been made possible in recent years by the development of high-current low-energy accelerators as well as enhanced target and detection methods. Nevertheless, the presence of atomic electrons, which alter the Coulomb barrier by screening the nuclear charge and increase the cross section at low energies compared to the case of bare nuclei, complicates these observations. A review of the experimental and corresponding theoretical work on laboratory electron screening performed so far will be presented. [ABSTRACT FROM AUTHOR]

The harmonic structure of lower hybrid waves (LHWs) driven by energetic ions can be generated through non‐linear wave‐wave coupling. We investigate the parameter dependence of the excitation and time evolution of this structure, using one‐dimensional electromagnetic particle‐in‐cell (PIC) simulations. Focusing on two parameters, ωpe/Ωe ${\omega }_{pe}/{{\Omega }}_{e}$ (ratio of the electron plasma to electron gyro frequencies) and u⊥/vA<1 ${u}_{\perp }/{v}_{A}< 1$ (ratio of energetic‐ion to Alfvén velocities), we analyze the fluctuation spectra in the wavenumber‐frequency plane and demonstrate that the harmonic structure can be excited across wide parameter ranges of 0.25≤ωpe/Ωe≤4 $0.25\le {\omega }_{pe}/{{\Omega }}_{e}\le 4$ and u⊥/vA<1 ${u}_{\perp }/{v}_{A}< 1$, indicating a weak parameter dependence. However, the excitation region and time evolution of the harmonic structure can be significantly affected by these parameters. We find that conditions of low ωpe/Ωe ${\omega }_{pe}/{{\Omega }}_{e}$ and intermediate u⊥/vA ${u}_{\perp }/{v}_{A}$ are preferable for the excitation and survival of the harmonic structure. Previous observations have reported the harmonic structure of LHWs in the polar region at 4,000 km altitude and in the plasma sheet at XGSM ∼ ${\sim} $ 17 RE ${R}_{\mathrm{E}}$. Nevertheless, this study predicts that the harmonic structure can also be excited in other regions of the magnetosphere where energetic ions are present. Plain Language Summary: The harmonic structure of lower hybrid waves (LHWs) can be generated through non‐linear wave‐wave coupling in association with LHW instabilities driven by energetic ions. To investigate the general condition of the excitation and time evolution of the harmonic structure, we conduct kinetic simulations for many cases focusing on the frequency ratio ωpe/Ωe $\left({\omega }_{pe}/{{\Omega }}_{e}\right)$ and the ratio of energetic‐ion to Alfvén velocities u⊥/vA $\left({u}_{\perp }/{v}_{A}\right)$. We find that the harmonic structure of LHWs can be excited under wide parameter ranges of ωpe/Ωe ${\omega }_{pe}/{{\Omega }}_{e}$ and u⊥/vA ${u}_{\perp }/{v}_{A}$, indicating a weak parameter dependence. However, the excitation region and time evolution can be significantly affected by the two parameters. Our findings can increase the possibility that the harmonic structure of LHWs can be excited in the Earth's magnetosphere. Key Points: The harmonic structure of lower hybrid waves (LHWs) driven by energetic ions can be generated through non‐linear wave‐wave couplingWe investigate the parameter dependence of the harmonic structure, paying attention to the two parameters of ωpe/Ωe ${\omega }_{pe}/{{\Omega }}_{e}$ and u⊥/vA ${u}_{\perp }/{v}_{A}$The harmonic structure can be excited under wide parameter ranges of ωpe/Ωe ${\omega }_{pe}/{{\Omega }}_{e}$ and u⊥/vA ${u}_{\perp }/{v}_{A}$, but its time evolution can depend on ωpe/Ωe ${\omega }_{pe}/{{\Omega }}_{e}$ and u⊥/vA ${u}_{\perp }/{v}_{A}$ [ABSTRACT FROM AUTHOR]

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In this work, the glow spectrum from a neon strip lamp, used in homes and all private places, was diagnosed using optical emission spectroscopy (OES), to measure plasma parameters from spectral data (electrons density, electrons temperature, plasma frequency, Debye length). The intensity of the emission spectrum increases with increasing the applied voltage (100-220V). A spectral diagnosis was made of the cold plasma generated by the neon glow system where the glow spectrum produced was prepared for the diagnosis at variable alternating voltages that begin to rise gradually. The diagnosis was made at atmospheric pressure and room temperature of 27 ̊C. The results showed a gradual increase in the intensity of the neon spectrum generated by the system with the amount of gradual increase in the applied voltage. Between (250-850) nm, the behavior of neon spectral lines varied between high and low spectral intensity peaks. [ABSTRACT FROM AUTHOR]

A heavy ion beam probe (HIBP) diagnostic is being developed for studies of plasma equilibrium and turbulence in the optimized Wendelstein 7-X (W7-X) stellarator. Operation of W7-X has experimentally demonstrated that its optimized magnetic field results in improved neoclassical particle confinement and, as a result, turbulence is the predominant cause of energy transport. The HIBP will have the unique ability to provide experimental data needed to complement models of both neoclassical and turbulent transport. It will acquire direct measurements in the W7-X plasma interior of the electric potential (needed for understanding ambipolar particle flux) and fluctuations of electron density and potential (needed for understanding turbulence). The HIBP for W7-X will inject singly charged ion beams with energies of up to 2 MeV and is designed to access the upper cross section of the W7-X plasma. We use trajectory simulations to illustrate the plasma coverage that the diagnostic can achieve in the reference magnetic configurations of W7-X. We calculate beam signal levels, discuss anticipated measurement sensitivity of broadband fluctuations of electron density and plasma potential, and show how they depend on plasma density. We also discuss the diagnostic sensitivity to equilibrium plasma potential. [ABSTRACT FROM AUTHOR]

The effects of the helical trajectories of the perturbing electrons in magnetized plasmas on the dynamical Stark width of hydrogen or deuterium spectral lines have been studied analytically in our previous two papers—specifically in the situation where the magnetic field B is so strong that the dynamical Stark width of these lines reduces to the so-called adiabatic Stark width because the so-called nonadiabatic Stark width is completely suppressed. This situation corresponds, for example, to DA and DBA white dwarfs. We obtained those analytical results by using the formalism of the so-called conventional (or standard) theory of the impact Stark broadening: namely, by performing calculations in the second order of the Dyson perturbation expansion. The primary outcome was that the dynamical Stark broadening was found to not depend on the magnetic field B (for sufficiently strong B). In the present paper, we use the O4 symmetry of hydrogen atoms for performing the corresponding non-perturbative analytical calculations equivalent to accounting for all orders of the Dyson perturbation expansion. The results, obtained by using the O4 symmetry of hydrogen atoms, differ from our previous ones not only quantitatively, but—most importantly—qualitatively. Namely, the dynamical Stark broadening does depend on the magnetic field B, even for strong B. These results should be important for revising the interpretation of the hydrogen Balmer lines observed in DA and DBA white dwarfs. We also address confusion in the literature on this subject. [ABSTRACT FROM AUTHOR]

In collisionless plasma, the function of an externally imposed static electric field has been investigated for facilitating the generation of high-power terahertz (THz) radiation. A nonlinear transient current density occurs at THz radiation frequency due to the optical rectification of high-power laser pulse having secant hyperbolic temporal intensity profile. This transient current driving a THz radiation is found to be strongly depended on the pulse width of laser, electron plasma frequency, and externally applied electric field. The effect of mismatched phase between the generated THz wave and laser has also been studied. Numerical simulations show that the strength of THz amplitude initially increases with propagation distance and then decreases. [ABSTRACT FROM AUTHOR]

We present details of recent extensions of the runaway electron (RE) fluid model implemented in the fusion magnetohydrodynamics code JOREK [M. Hoelzl et al., Nucl. Fusion 61, 065001 (2021)] to include the effects of partially ionized impurity species and deuterium neutrals. The model treats the interaction of runaway electrons with the background plasma via current-coupling. The code is separately benchmarked using ITER (https://www.iter.org/) relevant scenarios, with the GO [G. Papp et al., Nucl. Fusion 53, 123017 (2013)] code in relation to runaway electron beam formation and with the DINA [Khayrutdinov and Lukash, J. Comp. Phys. 109(2), 193–201 (1993)] code in relation to simultaneous runaway beam formation and vertical plasma motion. Benchmark results show a decent agreement in both the cases, which are also discussed. [ABSTRACT FROM AUTHOR]

Knowing the characteristic relaxation time of free electrons in a dense plasma is crucial to our understanding of plasma equilibration and transport. However, experimental investigations of electron relaxation dynamics have been hindered by the ultrafast, sub-femtosecond timescales on which these interactions typically take place. Here, we propose a novel approach that uses x rays from a free electron laser to generate well-defined non-thermal electron distributions, which can then be tracked via emission spectroscopy from radiative recombination as they thermalize. Collisional radiative simulations reveal how this method can enable the measurement of electron relaxation timescales in situ, shedding light on the applicability and accuracy of the Coulomb logarithm framework for modeling collisions in dense plasmas. [ABSTRACT FROM AUTHOR]

We use the full NASA Van Allen Probes mission (2012–2019) to extract the electron plasma density from the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) and Electric Field and Waves (EFW) instruments and discuss the evolution of the plasmasphere. We generate new statistics including mean and standard deviations of the plasma density with respect to L‐shell, magnetic local time (MLT), and various geomagnetic indices. These statistics are generated to be applied in radiation belt physics and space weather codes (with fits provided). The mean plasmasphere is circular around Earth with respect to MLT for Kp < 1. The mean 100 cm−3 level line is above L = 5 and mean 10 cm−3 level expands above the Van Allen Probes apogee for Kp < 1. The outer electron belt lies within the plasmasphere for 60% of all times. As activity increases (Kp > 2), a gradual MLT asymmetry forms with higher mean density in the afternoon sector due to plumes expanding outward. Conversely, the mean density decreases on the dawn and night sectors. The mean density is between ∼500 and ∼50 cm−3 between L ∼ 4 and L ∼ 6 during quiet and moderately active times (Kp < 3), representing ∼80% of all times. Statistics in regions of high density below L = 2 are underdefined for intense activity. The highest standard deviation of density represents a factor 2.5 to 3 times the mean above L = 5 and for active times. We find the percent difference between the EFW and EMFISIS densities is bounded by ±20% for quiet and moderate activity (Kp < 5) and goes up to ±100% for extreme activity. Plain Language Summary: The Earth's plasmasphere, discovered in the 1950s, is a region of cold plasma made of ions and electrons of a few electronvolts in energy, originating from upwelling ionized gas from the ionosphere and forming a rotating torus around the Earth. The radial profile of the electron cold plasma density within the plasmasphere decays from 10,000 electrons per cubic centimeter at ∼1,000 km altitude to 10s electrons per cubic centimeter at its outer edge, sometimes exceeding ∼36,000 km in altitude at the equator. The state of the plasmasphere is highly dependent on geomagnetic conditions, with geomagnetic storms and substorms eroding parts of this plasma. Here, we analyze 7 years of NASA Van Allen Probes measurements of the electron plasma density and generate statistics with respect to L‐shell, magnetic local time, and geomagnetic indices. In this way, we show statistical variations of the plasmasphere, a strong magnetic local time dependence, and erosion with increasing geomagnetic activity. New mean electron densities and their standard deviation are generated and fitted with model functions that can be incorporated into space weather codes. This is important because the electron density is a key parameter influencing the strength of wave‐particle interactions that accelerate and scatter energetic particles in the inner magnetosphere. Key Points: Generation of new statistics of mean and standard deviation of the plasma density from Electric Field and Waves and Electric and Magnetic Field Instrument Suite and Integrated Science of RBSP for the whole missionEmpirical density models made of fits are provided versus L‐shell, magnetic local time (MLT), and geomagnetic indices to be used in radiation belt codesAn extensive analysis of the cold plasma statistics is provided with respect to L‐shell, MLT, and geomagnetic activity [ABSTRACT FROM AUTHOR]

Electron cyclotron harmonic (ECH) waves are electrostatic emissions with frequencies between the harmonics of the electron gyrofrequencies. Their frequency properties provide clues for understanding their generation and are keys to evaluating their scattering efficiency. Based on Magnetospheric Multiscale satellite observations, we explored the statistical frequency properties of first‐harmonic band ECH waves in the outer magnetosphere. The frequencies at the peak power of ECH waves are found to be day‐night and dawn‐dusk asymmetries, with higher values in the regions from dawn to post‐noon, and these asymmetries are more evident during weaker geomagnetic activity. Furthermore, the frequencies at the peak power of ECH waves decrease gradually with increasing |MLAT| and are positively correlated with their amplitudes at each magnetic local time or |MLAT|. Information on the frequency properties of ECH waves presented in this study can be crucial for future modeling of their contributions to magnetospheric electron dynamics. Plain Language Summary: Electron cyclotron harmonic (ECH) waves are electrostatic emissions with frequencies between the harmonics of the electron cyclotron frequency. They act as major contributors to the generation of diffuse auroras in the outer magnetosphere via the pitch angle scattering of plasma sheet electrons into the atmosphere. Theoretically, such electron scattering can be quantified by quasilinear scattering rates, which are strongly controlled by the wave frequency. However, the current knowledge of their frequency properties is lacking. In this study, we statistically analyze the frequency properties of the first‐harmonic band ECH waves in the outer magnetosphere using Magnetospheric Multiscale satellite observations. The statistical results show that the wave frequency at peak power highly depends on the magnetic local time (MLT), magnetic latitude (MLAT), and wave amplitude. These new findings are of great importance in advancing our knowledge of ECH wave generation and in modeling ECH‐induced plasma sheet electron dynamics in the outer magnetosphere. Key Points: ECH waves have clear frequency distribution patterns depending on the MLT, MLAT, and wave amplitudeThe frequency at the peak power is larger from dawn to post‐noon, maximized near the magnetic equator, and decreases with increasing |MLAT|The frequency at the peak power increases with the amplitude for each specific magnetic local time or |MLAT| [ABSTRACT FROM AUTHOR]

Context. The Mercury electron analyzer (MEA) obtained new electron observations during the first three Mercury flybys by BepiColombo on October 1, 2021 (MFB1), June 23 , 2022 (MFB2), and June 19, 2023 (MFB3). BepiColombo entered the dusk side magnetotail from the flank magnetosheath in the northern hemisphere, crossed the Mercury solar orbital equator around midnight in the magnetotail, traveled from midnight to dawn in the southern hemisphere near the closest approach, and exited from the post-dawn magnetosphere into the dayside magnetosheath. Aims. We aim to identify the magnetospheric boundaries and describe the structure and dynamics of the electron populations observed in the various regions explored along the flyby trajectories. Methods. We derive 4s time resolution electron densities and temperatures from MEA observations. We compare and contrast our new BepiColombo electron observations with those obtained from the Mariner 10 scanning electron spectrometer (SES) 49 yr ago. Results. A comparison to the averaged magnetospheric boundary crossings of MESSENGER indicates that the magnetosphere of Mercury was compressed during MFB1, close to its average state during MFB2, and highly compressed during MFB3. Our new MEA observations reveal the presence of a wake effect very close behind Mercury when BepiColombo entered the shadow region, a significant dusk-dawn asymmetry in electron fluxes in the nightside magnetosphere, and strongly fluctuating electrons with energies above 100s eV in the dawnside magnetosphere. Magnetospheric electron densities and temperatures are in the range of 10–30 cm−3 and above a few 100s eV in the pre-midnight-sector, and in the range of 1–100 cm−3 and well below 100 eV in the post-midnight sector, respectively. Conclusions. The MEA electron observations of different solar wind properties encountered during the first three Mercury flybys reveal the highly dynamic response and variability of the solar wind-magnetosphere interactions at Mercury. A good match is found between the electron plasma parameters derived by MEA in the various regions of the Hermean environment and similar ones derived in a few cases from other instruments on board BepiColombo. [ABSTRACT FROM AUTHOR]

The plasmon pole approximation used for the stopping function in a dense electron plasma is given a temperature‐dependent cutoff wavenumber via the ion projectile thermal wavelength. Excepted for projectile inter‐ion distance smaller than the target electron screening length and small ion fragment velocities, featuring a attosecond interaction time with a maximum correlated ion stopping (CIS) in inertial confinement fusion and warm dense matter (WDM), the given procedure is shown to yield back accurately the CIS estimated within the standard random phase approximation framework at any temperature, provided the ion fragment distribution is taken Gaussian. [ABSTRACT FROM AUTHOR]

This research scrutinizes the impact of external magnetic field strength variations on plasma jet parameters to enhance its performance and flexibility. Plasma jets are widely used for their high thermal and kinetic energy in both medical and industrial fields. The study employs optical emission spectroscopy to measure electron temperature, electron density, and plasma frequency in a plasma jet subjected to varying magnetic field strengths (25, 50, 100, 150, and 250 mT). The results indicate that a stronger magnetic field results in higher electron temperature (1.485 to 1.991 eV), electron density (5.405 × 1017 to 7.095 × 1017), and plasma frequency 7.382 × 1012 to 8.253 × 1012 Hz. As well as the research investigates the influence of gas flow rate on gas temperature in the plasma jet. It is observed that gas temperature gradually drops with a growth in the flow rate of argon gas. The voltage and current waves have a sinusoidal waveform without elevation lines and with decaying waveforms. The existence of a strong magnetic field generates magnetohydrodynamic instability, leading to the plasma jet flame splitting. Understanding the effects of changing the strength of the external magnetic field on the plasma properties provides the ability to control the plasma Permart to make it suitable for many applications. [ABSTRACT FROM AUTHOR]

A mutual impedance probe was developed at the Physical research Laboratory, Ahmedabad and flown on a Nike-Apache rocket launched from Thumba, near the magnetic equator in India near noon on 3 March 1973. The experimental details and the results obtained are presented in this communication. Electron density values obtained from Langmuir probe during the same flight are close to values obtained from impedance probe. [ABSTRACT FROM AUTHOR]

In 1980, Prof. Bimla Buti derived, for the first time, an exact solution for localized nonlinear ion-acoustic waves in a plasma with two electron components. Her theory predicted that in the presence of a second electron component, ion-acoustic holes (i.e., solitons with density dips) can exist in addition to regular ion-acoustic solitons having density humps. In 1982, Temerin, et al. [1] reported the observations of ion holes in the Earth's auroral acceleration region between 6000 and 8000 km altitude by S3-3 spacecraft, thus confirming the theoretical predictions of Buti's model. Later on, ion holes were observed on auroral field lines by the Viking spacecraft [2,3] and the Polar spacecraft [4]. It is indeed a nice example where theory leads space experiments and observations. [ABSTRACT FROM AUTHOR]

A review of recent advances in simulations of turbulent filaments with relevance to stellarators is presented. Progress in performing global edge turbulence simulations is discussed as well as results from seeded filament simulations with applications to the unique environment of a stellarator island divertor-including abrupt changes in connection length and highly-nonuniform curvature drive. It is determined that the motion of filaments generally follows the average curvature, but strong nonuniform perturbations can shear a filament and reduce the overall transport. The coherence of filament transport is also determined to be influenced by the collisionality and electron plasma beta. By simplifying the simulation geometries, large parameter scans can be performed which accurately reflect the macroscopic transport of filaments observed in Wendelstein 7-X. Comparisons to experiments are discussed, and a the develeopment of a synthetic diagnostic has been able to inform experimental measurements by quantifying potential sources of error in filament propagation measurements. A discussion of the necessary extension to more complex multifluid models, and the scope for near-term filament simulations in stellarators, is provided. [ABSTRACT FROM AUTHOR]

This study determined the electron temperature and density in atmospheric pressure argon plasma using optical emission spectroscopy. The analysis combined continuum and line spectral data. Visible bremsstrahlung inversion was used to derive a partial electron energy probability function (EEPF) from the continuum spectrum. Subsequently, electron temperature was estimated assuming a two-temperature distribution based on the derived EEPF. Electron density was obtained by fitting a collisional-radiative (CR) model to the line spectrum, incorporating the obtained EEPF instead of assuming a Druyvesteynian EEPF. Comparative analysis revealed that the electron densities determined using the approach were approximately one order of magnitude lower than those derived from the CR model with the Druyvesteynian EEPF. However, they exhibited strong agreement with the results obtained by the CR model using a two-temperature distribution. This approach demonstrated favorable performance in reproducing both continuum and line spectra, revealing its high reliability and accuracy for atmospheric pressure argon plasma diagnosis. [ABSTRACT FROM AUTHOR]

A theoretical investigation of the phase-mixing phenomenon of Langmuir oscillations (LOs) in a multi-component dusty plasma is presented. The plasma under study is a four-component plasma consisting of electrons, positrons, singly ionised positive ions and positive (or negative) polarity dust grains. The massive dust grains are assumed to form a fixed charge neutralising background, while the electrons, positrons and ions are considered to take part in the wave dynamics. A simple perturbative analysis of the governing fluid-Maxwell's equations leads us to an approximate relation for phase-mixing time of LOs, improving some earlier existing results. It is revealed that even though the dust grains remain motionless in the background, they still have significant impact on the phase-mixing process of LOs in such plasmas. It is found that the nature of the charge on the dust grains and the equilibrium dust density profoundly affect the phase-mixing time. The results of this investigation is expected to have relevance in space-plasma environments. [ABSTRACT FROM AUTHOR]

This manuscript explores the plasmonic characteristics of monolayer graphene in anisotropic plasma dielectric planar structure. The complex conductivity of monolayer graphene is modeled by Kubo formulism. Due to anisotropy of plasma medium, higher and lower modes are demonstrated to explore the properties of proposed waveguide structure. Incident frequency-dependent both propagating modes are discussed for normalized phase constant as well as phase velocity under the different values of chemical potential, relaxation time, number of graphene layers, electron plasma frequency and cyclotron frequency. Field profiles for anisotropic dielectric are also presented to confirm electromagnetic surface waves condition. The presented results are being used to increase the efficiency of a graphene-based chip photonic system. [ABSTRACT FROM AUTHOR]

In the Earth's magnetosheath (MSH), several processes contribute to energy dissipation and plasma heating, one of which is wave‐particle interactions between whistler waves and electrons. However, the overall impact of whistlers on electron dynamics in the MSH remains to be quantified. We analyze 18 hr of burst‐mode measurements from the Magnetospheric Multiscale (MMS) mission, including data from the unbiased magnetosheath campaign during February‐March 2023. We present a statistical study of 34,409 whistler waves found using automatic detection. We compare wave occurrence in the different MSH geometries and find three times higher occurrence in the quasi‐perpendicular MSH compared to the quasi‐parallel case. We also study the wave properties and find that the waves propagate quasi‐parallel to the background magnetic field, have a median frequency of 0.2 times the electron cyclotron frequency, median amplitude of 0.03–0.06 nT (30–60 pT), and median duration of a few tens of wave periods. The whistler waves are preferentially observed in local magnetic dips and density peaks and are not associated with an increased temperature anisotropy. Also, almost no whistlers are observed in regions with parallel electron plasma beta lower than 0.1. Importantly, when estimating pitch‐angle diffusion times we find that the whistler waves cause significant pitch‐angle scattering of electrons in the MSH. Key Points: Whistlers exist throughout the magnetosheath with higher occurrence in the quasi‐perpendicular geometry and in local magnetic field dipsWhistlers are observed in regions with electron beta above 0.1 and are not correlated with electron temperature anisotropyWhistlers cause significant pitch‐angle scattering of magnetosheath electrons [ABSTRACT FROM AUTHOR]

Based on correlated magnetosphere‐ionosphere (M‐I) conjugate observations of seven events, we study the hot zone developed under short‐circuiting conditions leading (a) to the development of outward Subauroral Polarization Streams (SAPS) or Subauroral Ion Drifts (SAID) electric (E) field and (b) to the various subauroral arcs' absence or presence. Results show (a) the close relations of the hot zone earthward extent and peak ion temperature (Ti) to the magnitude of outward SAPS/SAID E field and (b) the hot zone's high Ti (∼11,000 eV) developed under enhanced plasma turbulence that was (c) generated by the amplified narrow hot ion and electron plasma density peaks, (d) sometimes in plasmaspheric plumes, and that was (e) sometimes further enhanced by the strong auroral kilometric radiation (AKR) waves (f) leading to the development of enhanced SAPS/SAID E field. From these (a–f) findings we conclude for the seven events investigated that (a) the hot zone's development under short‐circuiting conditions was regulated by the kinetic energy of mesoscale plasma flows and that (b) the hot zone created the favorable inner‐magnetosphere conditions during short circuiting (c) for stable auroral red (SAR) arc development by plasma turbulence, which is the common source of heat/suprathermal particles accelerated downward, and (d) in the plasmaspheric plume scenario for SAR arc and Strong Thermal Emission Velocity Enhancement (STEVE) arc development by the plumes' enhanced cold plasma populations leading to strong shear flows and thus shear‐flow instabilities well‐known associated with the SAPS/SAR arc and recently regarded as a potential driver mechanism of the STEVE arc. Key Points: The hot zone's development under short‐circuiting conditions was regulated by the kinetic energy of mesoscale plasma flowsThe hot zone created favorable inner‐magnetosphere conditions for the development of stable auroral red arc by plasma turbulenceStrong Thermal Emission Velocity Enhancement arc development was favored by the plasmaspheric plume related shear flows [ABSTRACT FROM AUTHOR]

The intense electron‐scale current structures (ECSs) with the current density J ≥ 30 nA/m2 are often observed in the Plasma Sheet (PS) during high‐speed bulk flows. Using MMS observations we have analyzed 41 earthward and 37 tailward flow intervals and found 452 and 754 ECSs distributed over the PS region, respectively. Almost all ECSs are generated by high‐speed electron beams. The duration of ECSs is ≤1 s, and many of them have a half‐thickness L ≤ a few ρe (ρe is the gyroradius of thermal electrons). In such thin ECSs electrons become demagnetized and experience the dynamics like that observed in the electron diffusion region. Strong nonideal electric fields (E') associated with violation of frozen‐in condition for electrons are observed in the ECSs. This results in the intense energy conversion with J·E' up to hundreds pW/m3. The major part of the dissipating energy is transferred to electron heating and acceleration. We suggest that the ECSs are manifestations of kinetic‐scale turbulence driven by the high‐speed ion bulk flows. The inductive electric fields generated by the growing magnetic fluctuations accelerate electron beams which, in turn, generate the ECSs. The ECSs thinning during their evolution, probably, stops for L ≤ a few ρe. Further thinning leads to development of kinetic instability causing the current disruption and strong electric field generation. The last accelerates new electron beams which generate new ECSs in other locations. Thus, the life cycles of the ECSs contribute to energy cascade in turbulent plasma at electron kinetic scales. Key Points: Electron‐scale current structures (ECSs) with a few L/ρe thickness are observed in the plasma sheet during fast ion bulk flowsThe ECSs are mostly generated by demagnetized electrons experiencing the dynamics similar to that observed in electron diffusion regionIn the ECSs J·E' reaches the values typical for EDR, thus, they significantly contribute to the turbulent energy cascade at electron scales [ABSTRACT FROM AUTHOR]

An analysis of the observational polarization properties of the decameter spikes is presented in the paper. It is shown that decameter spikes possess high degree of circular polarization with average value of about 60%. In the frames of "leading spot" theory we associated the spikes activity with a certain active region on the solar disk and determined the mode of the emission. Supposing plasma emission mechanism we link and determine coronal plasma and fast electron beam parameters. [ABSTRACT FROM AUTHOR]

In this study, an air-water vapor ionization reaction model is developed within the quantum-kinetic (Q–K) model of the direct simulation Monte Carlo method to investigate the detailed mechanism of how water vapor reduces electrons. The zero-dimensional simulations of a typical non-equilibrium flow field downstream of a normal shock are designed, where the electron number density decreases by two orders of magnitude due to water vapor. We conclude that the introduction of water vapor reduces the mole fractions of oxygen atoms and nitrogen atoms through five pairs of reactions and enhances the reverse nitric oxide associative ionization reaction, leading to electron consumption. The phenomena and corresponding mechanisms under varying mole fractions of water vapor, air temperatures, and water vapor temperatures are investigated. Based on the mechanisms, we propose that the addition of hydrogen ions could improve the water's mitigation effect, which is then proven to be able to reduce the electron number density by another two orders of magnitude, not only at high air temperatures but also at lower air temperatures or lower mass injection rates. [ABSTRACT FROM AUTHOR]

The distinctive features of the T-15MD tokamak microwave interferometer for measuring linearly integrated electron density, as well as the system for processing and recording its signals, are presented. The phase stability of microwave interferometer signals is analyzed. The results of measurements with a microwave interferometer during the first experimental campaign of the T-15MD tokamak are presented. The phase values were extracted by using an analog phase meter and post-processing of digitized microwave interferometer signals: an intermediate frequency signal and a local oscillator signal. It is shown that the results of the plasma density calculation by these two methods coincide. [ABSTRACT FROM AUTHOR]

The problem of signal amplification in a plasma microwave amplifier is considered in the linear approximation and with allowance for nonlinear effects leading to saturation of instability. The solutions of the exact dispersion equation and an approximate dispersion equation used in calculation of parameters of plasma microwave amplifiers are compared. It is shown that the solutions of these equations in the region of high frequencies are significantly different. Nonlinear dynamics of beam–plasma instability in plasma microwave amplifiers is described by a system of differential equations which is obtained by the slowly varying amplitude method and yields an approximate dispersion equation when it is linearized. A method for modifying parameters of a nonlinear system of differential equations to make it consistent with the exact dispersion equation is proposed and the calculation results are demonstrated. [ABSTRACT FROM AUTHOR]

The possibility of using plasma electron spectroscopy (PLES) as a practical method for the detection and identification of crystalline impurities of salts: silver salts, as well as ammonium salts, used in explosives and dangerous substances is shown. To create a prototype of the PLES detector, relatively simple technical solutions are adopted. The source of excitation of metastable atoms is a short DC glow discharge. For analysis, probe scheme for registering electric current from an auxiliary additional electrode probe is used when scanning the retarding electric potential. As a result of a series of experiments, the possibility of detecting products, cathode sputtering, and decomposition of ammonium and silver salts was shown. In particular, peaks from ammonia, nitrogen oxide, silver, and chlorine were recorded. [ABSTRACT FROM AUTHOR]

Disorder-induced heating (DIH) prevents ultracold neutral plasma into the electron strong coupling regime. Here, we propose a scheme to suppress electronic DIH via optical lattice. We simulate the evolution dynamics of ultracold neutral plasma constrained by three-dimensional optical lattice using the classical molecular dynamics method. The results show that for experimentally achievable conditions, electronic DIH is suppressed by a factor of 1.3, and the Coulomb coupling strength can reach 0.8, which is approaching the strong coupling regime. Suppressing electronic DIH via optical lattice may pave a way for the research of electronic strongly coupled plasma. [ABSTRACT FROM AUTHOR]

Initially, elliptical, quasi-two-dimensional (2D) fluid vortices can split into multiple pieces if the aspect ratio is sufficiently large due to the growth and saturation of perturbations known as Love modes on the vortex edge. Presented here are experiments and numerical simulations, showing that the aspect ratio threshold for vortex splitting is significantly higher for vortices with realistic, smooth edges than that predicted by a simple "vortex patch" model, where the vorticity is treated as piecewise constant inside a deformable boundary. The experiments are conducted by exploiting the E × B drift dynamics of collisionless, pure electron plasmas in a Penning–Malmberg trap, which closely model 2D vortex dynamics due to an isomorphism between the Drift–Poisson equations describing the plasmas and the Euler equations describing ideal fluids. The simulations use a particle-in-cell method to model the evolution of a set of point vortices. The aspect ratio splitting threshold ranges up to about twice as large as the vortex patch prediction and depends on the edge vorticity gradient. This is thought to be due to spatial Landau damping, which decreases the vortex aspect ratio over time and, thus, stabilizes the Love modes. Near the threshold, asymmetric splitting events are observed in which one of the split products contains much less circulation than the other. These results are relevant to a wide range of quasi-2D fluid systems, including geophysical fluids, astrophysical disks, and drift-wave eddies in tokamak plasmas. [ABSTRACT FROM AUTHOR]

Plasma confinement was succeeded by an optoelectronic system with the aid of a vacuum ultraviolet (VUV) light source, called the photoemission-assisted plasma system. The photoemission-assisted plasma was generated by utilizing photoelectrons from the substrate cathode. The photoelectrons were emitted from the substrate by external VUV irradiation via the photoelectric effect and then worked as initial electrons triggering the plasma generation. The photoemission-assisted plasma was confined with bright luminescence in an argon atmosphere by controlling the flow rate and pressure. The plasma confinement survived at up to 6400 Pa, which was much higher than the pressure estimated from the current–voltage characteristics. These results suggested that the area exhibiting luminescence dominated by the γ regime becomes small as the argon flow rate increases; however, the area does not vanish because the VUV-excited photoelectrons are sufficiently supplied. The residual area is dominated by the α regime without luminescence. Thus, the photoemission-assisted plasma seems to be confined on the balance between α and γ regimes. Because the current in the α-regime area is one hundredth in magnitude compared with that in the γ-regime area, the actual current density results in over 40 times with strong luminescence. This confined plasma with certain voltage and current condition may be expected for developing a new plasma reaction system and for application in semiconductor engineering. [ABSTRACT FROM AUTHOR]

Electron cyclotron resonance heating method of Particle-in-Cell code was used to analyze heating phenomena, axial kinetic energy, and self-consistent electric field of confined electron plasma in ELTRAP device by hydrogen and helium background gases. The electromagnetic simulations were performed at a constant power of 3.8 V for different RF drives (0.5 GHz– 8 GHz), as well as for 1 GHz constant frequency at these varying amplitudes (1 V—3.8 V). The impacts of axial and radial temperatures were found maximum at 1.8 V and 5 GHz as compared to other amplitudes and frequencies for both background gases. These effects are higher at varying radio frequencies due to more ionization and secondary electrons production and maximum recorded radial temperature for hydrogen background gas was 170.41 eV. The axial kinetic energy impacts were found more effective in the outer radial part (between 0.03 and 0.04 meters) of the ELTRAP device due to applied VRF through C8 electrode. The self-consistent electric field was found higher for helium background gas at 5 GHz RF than other amplitudes and radio frequencies. The excitation and ionization rates were found to be higher along the radial direction (r-axis) than the axial direction (z-axis) in helium background gas as compared to hydrogen background gas. The current studies are advantageous for nuclear physics applications, beam physics, microelectronics, coherent radiation devices and also in magnetrons. [ABSTRACT FROM AUTHOR]

The fundamental difference between quantum and traditional plasmas is the electron and ion composition, the former has a much higher density and extremely lower temperature, and it can be modelled by Zakharov-Kuznetsov (ZK) equation. In this paper, the Hirota bilinear method is used to study its solution properties. [ABSTRACT FROM AUTHOR]

An experiment was set up to study the afterglow of an extended barrier discharge in low-pressure neon containing Ne+, Ne2+, and Ne++ ions by kinetic spectroscopy. Observation conditions: neon pressure ~0.8–1.7 Torr, electron density in the afterglow stage [e] ~ 1011 cm–3. In order to compare the rates of collisional-radiative recombination of Ne+ and Ne++ ions, the effect of pulsed "heating" of decaying plasma electrons by a weak high-frequency field on the intensities of atomic and ion lines was observed. The presented data show that in such a plasma, short-term suppression of recombination processes by electron heating leads to an increase in the brightness of spectral lines in the atomic and ion afterglow spectra, and the reaction of the lines of the latter turns out to be much stronger. Based on simple estimates, it is shown that this effect is due to the difference in the recombination rates of the Ne+ and Ne++ ions, and this difference turns out to be beyond the scope of theoretical concepts. [ABSTRACT FROM AUTHOR]

Laser Wakefield Acceleration (LWFA) has emerged as a groundbreaking approach for generating ultra-high energy electron beams over short distances, revolutionizing the field of particle acceleration. In this paper, we investigate the novel concept of employing sin-Gaussian laser pulse for enhanced LWFA performance. sin-Gaussian pulses combine the advantageous features of both sinusoidal and Gaussian pulse shapes, offering unique opportunities for generating the plasma wakefield and optimizing electron acceleration. We present a comprehensive theoretical analysis of the interaction between a sin-Gaussian laser pulse and an underdense plasma medium, elucidating the intricate dynamics of the wakefield excitation and electron acceleration. Through analytical study, we demonstrate that the sin-Gaussian pulse configuration leads to a significant energy gain (Maximum gain of 2.06 GeV with chosen parameters) for plasma electrons. Furthermore, we explore the effects of varying key parameters such as the laser electric field amplitude and beam waist on the acceleration performance. Our findings reveal the underlying physics governing the interplay between these parameters and the resulting electron energy spectra for LWFA outcomes. [ABSTRACT FROM AUTHOR]