Values Of Plasma Parameters Research Articles

THREE DIFFERENT SPATIAL POSITIONS OF FAST MAGNETOSONIC WAVE COMPONENT TURNING POINTS

Two different approaches to defining the cut-off in a magnetoactive plasmas are well-known. In one approach, a physicist searches the cut-off frequency for uniform plasma, that is for fixed values of plasma parameters, such as the plasma composition, plasma particle densities and external static magnetic field. This cut-off frequency separates those frequencies, at which the electromagnetic wave is propagative, from those, at which it is evanescent one. In the other approach, a physicist searches the cut-off plasma particle density for the fixed frequency. The density is observed at the cut-off coordinate called in some text-books as “turning point” or “transition point”. This coordinate separates the space, within which the wave is propagative, from the space, within which the wave is evanescent one. The conditions for determining the turning points depend not only on the values of plasma parameters themselves but on the plasma parameter gradients as well. These conditions are determined for the case of the electromagnetic waves in ion cyclotron frequency range. Their deviation from the condition applied for the first approach is discussed.

Potential Impacts of Dried Green Coleus forskolin Leaves on Thermo-tolerance Parameters, Blood and Plasma Profiles in Anesthetized Mice

Background: Transient negative side effects of hypothermia, hyperglycemiaand bradycardia due to general anesthesia using diazepam and xylazine drugs has been reported in mice. Methods: Twenty albino male mice of 31.52±0.25 g body weight were classified into two groups; control group (G1) fed basal control diet versus C. forskolin group fed basal control diet containing C. forskolin leaves (G2; 1.5%) for four weeks. The mice were general anesthetized using xylazine and diazepam (XD) drugs (13.3 mg/kg BW diazepam and 26.6 mg/kg BW xylazine). Changes of rectal temperature (°C), glucose (mg/dl), pulse rate (pulse/min.) and partial pressure of oxygen (SPO2) were recorded at 0.0, 0.5h, 1.0h, 2.0h, 3.0h, 5.0h and 7.0h over general anesthesia. In addition, blood samples were collected and were subjected to blood and plasma analyses. Result: The results indicated that dietary C. forskolin caused significant decrease (P less than 0.05) in glucose values in addition to significant increase (P less than 0.05) in rectal temperature, pulse rate and SPO2 during the period hypothermia, hyperglycemiaand bradycardia over general anesthesia. In addition, values of blood (RBCs, WBCs, PCV and Hb) and plasma parameters (TP, BUN, creatinine, AST and ALT, LDH) were normal due to C. forskolin supplementation compared to control diet. It could be concluded that 1.5% C. forskolin supplementation modulates thermo-tolerance responses, blood glucose indices, blood and plasma metabolites over general anesthesia.

Spatial Distribution of the Eddy Diffusion Coefficient in the Plasma Sheet of Earth’s Magnetotail and its Dependence on the Interplanetary Magnetic Field and Geomagnetic Activity based on MMS Satellite Data

The article presents the results of a statistical analysis of the distribution of the eddy diffusion coef-ficient depending on the coordinates in the plasma sheet of Earth’s magnetosphere based on data from the Magnetospheric Multiscale Mission satellite system (MMS) for the period from 2017 to 2022. The localization of satellites inside the plasma sheet was recorded from the concentration and temperature of plasma ions according to the data of the same instruments and the value of plasma parameter β. Significant anisotropy of the eddy diffusion coefficient was revealed. The dependence of the eddy diffusion coefficient on the inter-planetary magnetic field is analyzed, showing that with the southern orientation of the interplanetary magnetic field, the eddy diffusion coefficients are 1.5–2 times greater than with the northern orientation. It is also shown that under disturbed geomagnetic conditions (SML –200 nT), the eddy diffusion coefficients are several times greater than under quiet geomagnetic conditions (SML –50 nT).

Influence of plasma on the optical appearance of spinning black hole in Kalb-Ramond gravity and its Existence around M87* and Sgr A*

The visible universe is filled with different types of plasma media in the form of stars, nebulas and other forms of excited gases. These matter fields have a high influence on the gravity and are likely to be present around the black holes due to the immense gravitational attraction. Since a plasma medium affects the speed of light, therefore we investigated the null geodesics and various optical features around the rotating black hole in Kalb-Ramond gravity immersed in plasma medium. Various plasma distributions are considered to develop a comparative study for their influence on unstable null circular orbits, shadows and evaporation rate of the black hole in the presence of a plasma medium. Moreover, the shadow results are also compared with Event Horizon Telescope data for M78* and Sgr A* in order to estimate the parametric bounds for which the rotating black hole in Kalb-Ramond gravity is considered either M87* or Sgr A* under the different values of plasma parameters. From this analysis, we also found the distribution of plasma that has a significant impact on the above mentioned features and is most likely to be present around M87* and Sgr A*.

Radiative dynamics of laser-driven Li@C n embedded in quantum plasma

This work considers a guest Lithium atom (Li@C n ) in an endohedral fullerene, embedded in a quantum plasma modeled by the more general exponential cosine screened Coulomb (MGECSC) potential, under the influence of a spherical confinement and laser radiation field. The system is examined in nonrelativistic form and the related wave equation is solved using the tridiagonal matrix method (TMM), thus obtaining the discrete-continuum spectrum and related wave functions. The numerical values of the relevant parameters in this process are physically accessible values. The effects of the plasma, laser field and endohedral cavity on the photoionization cross section (PCS) are analysed in detail. The shielding effect of the plasma medium and the pulsating effect of the laser field modify the effective potential energy of the system, affecting the localizations of the 2s and continuum states, causing various overlapping cases. Considering different values of the endohedral encompassement parameters, which means that different types of fullerenes are taken into account, overlapping cases occur for different spectra and wave functions. Scrutinising these overlappings, the confinement and Cooper resonances of the PCSs are analysed. This analysis provides many details for the radiative dynamics of an artificial system Li@C n . The relevant ranges and critical values of plasma, laser field, and endohedral encapsulation parameters in the formation process of these resonances and PCSs are explained, as well as the cross-section curves, resonance positions, effective photoelectron energy range, and general PCS behavior, which can be important for potential experiments in addition to other theoretical investigations.

Ion acoustic solitary waves in multicomponent plasmas: Influence of ion drift velocity and nonthermal electrons

AbstractIon acoustic solitary waves with arbitrary amplitude have been investigated using the Sagdeev potential (SP) method in a collisionless plasma consisting of non‐isothermal electrons, positrons, and positive ions. The SP has been obtained and the dependence of large amplitude solitary structures on various plasma parameters such as ion drift velocity , non‐thermal parameter , electron to positron temperature ratio , positron density , and Mach number have been studied. It is shown that, for the same values of plasma parameters, accounting for ion drift velocity greatly corrects the solitary wave profile.

Trivelpiece–Gould modes and low-frequency electron–ion instability of non-neutral plasma

The frequency spectra of the Trivelpiece–Gould modes of a waveguide partially filled with non-neutral plasma are determined numerically by solving the dispersion equation. The modes having azimuthal number $m = 1$ are considered. The results are presented for the entire acceptable range of electron densities, magnetic field strengths, for different values of the charge neutralization coefficient. The Cherenkov resonance condition of an ion with a diocotron mode having a finite value of the longitudinal wave vector was studied. The characteristics of resonant low-frequency electron–ion instability caused by relative azimuth motion of electrons and ions in crossed fields and by the anisotropy of the distribution function of ions are discussed. Ions are created by ionization of residual gas in the plasma volume. Due to the anisotropy, instability occurs not only in the vicinity of the resonance, but also outside it. For typical values of plasma parameters in experiments, estimations of the frequency growth rate are given. A conclusion is drawn that this instability can be the cause of the low-frequency oscillations observed in linear devices with non-neutral plasma produced in an electron beam channel.

On mechanisms for high-frequency pump-enhanced optical emissions at 557.7 and 630.0 nm from atomic oxygen in the high-latitude F-region ionosphere

Abstract. The EISCAT (European Incoherent Scatter Scientific Association) Heating facility was used to transmit powerful high-frequency (HF) electromagnetic waves into the F-region ionosphere to enhance optical emissions at 557.7 and 630.0 nm from atomic oxygen. The emissions were imaged by several stations of ALIS (Auroral Large Imaging System) in northern Sweden, and the EISCAT UHF incoherent scatter radar was used to obtain plasma parameter values. The ratio of the 557.7 to 630.0 nm column emission rates changed from I5577/I6300≈0.2 for the HF pump frequency f0=6.200 MHz ≈4.6fe to I5577/I6300≈0.5 when f0=5.423 MHz ≲4fe, where fe is the ionospheric electron gyro frequency. The observations are interpreted in terms of decreased electron heating efficiency and thereby weaker enhancement at 630.0 nm for f0=5.423 MHz ≲ 4 fe. The emissions at 557.7 nm are attributed to electron acceleration by upper hybrid waves of metre-scale wavelengths that can be excited with f0=5.423 MHz ≲ 4 fe.

Ion acoustic solitons at the acoustic speed in a warm negative ion plasma with superthermal electrons

Using the Sagdeev pseudopotential method, the existence of Korteweg–de Vries (KdV) and non-KdV solitons is investigated in a negative ion plasma comprising adiabatic positive and negative ions and kappa distributed electrons. For some plasma parameter values, the plasma model supports the coexistence of solitons of both polarities. Positive KdV solitons coexist with negative non-KdV solitons at low values of negative to positive ion density ratio, and positive non-KdV solitons coexist with negative KdV solitons at higher values. There is therefore a switch in polarity between positive KdV and negative KdV solitons at a critical value of negative to positive ion density ratio and a switch in polarity between negative non-KdV and positive non-KdV solitons at the same point. At the critical point, there is no soliton at the acoustic speed, although there is coexistence at larger Mach numbers. This confirms that the existence of a soliton at acoustic speed is not a necessary condition for the coexistence of solitons of both polarities. When electrons are strongly non-thermal and the ion temperatures are important, the coexistence region vanishes and the non-KdV solitons disappear with it. It was also found that there is a forbidden region in terms of negative (positive) ion temperatures when the negative (positive) ion temperature increases with the other plasma parameters held fixed.

The Trans-Heliospheric Survey

Context.Though the solar wind is characterized by spatial and temporal variability across a wide range of scales, long-term averages of in situ measurements have revealed clear radial trends: changes in average values of basic plasma parameters (e.g., density, temperature, and speed) and a magnetic field with a distance from the Sun.Aims.To establish our current understanding of the solar wind's average expansion through the heliosphere, data from multiple spacecraft needed to be combined and standardized into a single dataset.Methods.In this study, data from twelve heliospheric and planetary spacecraft - Parker Solar Probe (PSP), Helios 1 and 2, Mariner 2 and 10, Ulysses, Cassini, Pioneer 10 and 11, New Horizons, and Voyager 1 and 2 - were compiled into a dataset spanning over three orders of magnitude in heliocentric distance. To avoid introducing artifacts into this composite dataset, special attention was given to the solar cycle, spacecraft heliocentric elevation, and instrument calibration.Results.The radial trend in each parameter was found to be generally well described by a power-law fit, though up to two break points were identified in each fit.Conclusions.These radial trends are publicly released here to benefit research groups in the validation of global heliospheric simulations and in the development of new deep-space missions such as Interstellar Probe.

Effect of orbital angular momentum on dust-ion-acoustic waves in a superthermal plasma

Laser or electromagnetic radiation, in general, interacts with plasma in very interesting ways. In most cases, they induce orbital angular momentum (OAM) in such plasmas due to their polarization effects. Dust-ion-acoustic waves (DIAWs) with immovable dust particles are studied with the effect of rotation produced due to laser or electromagnetic interaction. The electrons are considered in the non-Maxwellian limit, with inertial ions and static dust grains possessing negative charges. Fluid theory is employed for obtaining the linear paraxial equation with regard to ion density perturbations. The fundamental Gaussian and Laguerre Gaussian (LG) beam solutions are talked over with the later being proved to be the source for OAM. By calculating the electrostatic potential for such linear waves, the components of the electric field with respect to the LG potential are shown. Finally, the energy density equation is used to calculate the OAM associated with DIAWs. The Laguerre Gauss mode is numerically shown to have greatly changed by varying the values of relevant plasma parameters, such as the electron superthermality parameter, radial and angular mode numbers, beam waist, and azimuthal angle. The present results may be useful in apprehending dust-ion-acoustic wave excitation due to Brillouin backscattering phenomenon of laser light interacting with plasma.

Diagnostics of laser-induced plasma from a thin film of oil on a silica wafer

In this study, plasma induced by a nanosecond Nd:YAG laser on thin oil films deposited on a silica wafer was characterized by evaluating the main plasma parameters. Spatially and temporally integrated spectral measurements were performed under experimental conditions optimized for elemental analysis of trace metals in oil. Time-resolved values of the spectral line intensities, electron number density, and plasma temperature were obtained from time-integrated measurements by subtracting averaged spectra recorded at different time delays. The electron number density was estimated using the Stark broadened profile of the hydrogen Balmer alpha line. Ionization temperatures were derived from Mg ionic to atomic line intensity ratios. The obtained apparent values of time-resolved plasma parameters were in the range of 1.1?1017 cm-3 (1.5 ?s) to 1.5?1016 cm-3 (4 ?s) and 9400 K (3 ?s) to 7200 K (5 ?s), depending on the delay time. Emission spectra of C2 and CN molecules were used to evaluate the rotational and vibrational temperature.

Parametric study of magnetically confined Cu-plasma by using optical emission spectroscopy (OES) and Faraday cup (FC) techniques

A parametric study of magnetically confined Nd:YAG laser induced Cu plasma was performed by using OES and FC techniques at different irradiances and pressures of Ar and Ne at different time delays. Both LIBS and FC analyses revealed that Cu plasma parameters (electron temperature (Te) electron/ion number density (ne/ni) are significantly enhanced in the presence of magnetic field. Without magnetic field under Ar environment, Te varies from 10,801 K to 8026 K, and ne of Cu plasma varies from1.6 × 1018 cm−3 to 0.9 × 1018 cm−3. Whereas, in the presence of magnetic field, these plasma parameters are enhanced from 12,648 K to 8300 K and from 1.6 × 1018 cm−3 to 1.03 × 1018 cm−3 respectively. FC measurements confirm that fluence of electrons and ions is increased in the presence of magnetic field from 2.6 × 1010 cm−2 to 4.2 × 1012 cm−2 and from 7.6 × 1011 cm−2 to 3.7 × 1012 cm−2 respectively. These higher values of Cu plasma parameters are attributed to Joule’s heating and adiabatic compressions after magnetic confinement.

Bifurcation types and dynamic control of dust ion‐acoustic waves propagation in dusty plasmas with non‐thermal electrons

AbstractThe bifurcation types and phase portraits of non‐linear dust ion‐acoustic travelling waves are studied in a dusty plasma comprising warm adiabatic ions, non‐thermal electrons and stationary cold dust species. A dynamical system is derived for the plasma waves evolution, and then the bifurcation response is determined on the equilibrium points‐non‐thermal parameter plane. It is shown that the motion dynamics of travelling waves undergoes a transcritical as well as saddle‐node bifurcations for the critical values of energetic electrons. We indicate that a sudden emergence and transition between solitary waves and non‐linear periodic waves occur at the critical point of transcritical bifurcation. For the saddle‐node bifurcation, we show that both solitary and super‐nonlinear periodic waves disappear, and only a large amplitude periodic wave can propagate in plasma. Further, the coexistence of solitary waves, non‐linear and super‐nonlinear waves are investigated for different values of plasma parameters. The results obtained here could be applicable to different space and astrophysical plasma systems, particularly in Saturn's E‐ring.

A comparison of the physiological responses to heat stress of juvenile and adult starry flounder (Platichthys stellatus)

Water temperature is the most important factor in fish farming as changes in water temperature cause physiological stress in fish. There have been few studies on physiological responses to high temperatures, which vary with aging. This study investigated the responses of juvenile and adult Platichthys stellatus to heat stress. Plasma cortisol, glucose, lactate, and lysozyme levels, antioxidant enzyme activities, and expression of heat shock proteins 70 and 90 (HSP70 and HSP90) of P. stellatus were determined at water temperatures of 16, 20, 24, 28, and 30°C. As a result, it was confirmed that several plasma parameters of adult were significantly higher than that of juvenile under heat stress. Plasma cortisol and glucose levels of adult were increased than juvenile at 24 and 28°C. Plasma lactate level of adult were higher than that of juvenile at 28°C. Comparisons of survival and physiological changes showed that juveniles have better thermal tolerance, resulting in a higher cumulative survival rate. Moreover, the relationship between thermal tolerance and HSP gene expression revealed that expression of HSP70 and HSP90 was significantly upregulated at 28°C in both juvenile and adult fish, and HSP70 expression was significantly higher in juvenile fish than in adult fish. It is judged that the adult’s HSP70 activity was lower than juvenile, so the demand for plasma parameters for heat response was relatively high, whereas juvenile’s HSP70 activity increased at 24 and 28°C, indicating a relatively stable value of plasma parameters. These results indicate that the thermal tolerance of juvenile fish is greater than that of adult fish, based on the differences in plasma parameters and HSP expression. These findings improve our understanding of age-related changes in P. stellatus during thermal stress and may help guide the management of fish farms.

Emission spectroscopy of negative hydrogen ion sources: From VUV to IR.

The target parameters of negative ion sources regarding the current of extracted negative ions, the current of co-extracted electrons, the pulse duration, the duty cycle, and the availability of the system can be rather strict. Knowledge of plasma parameters such as the electron temperature and the electron density and also properties of molecules or photon fluxes can provide essential insights into the ion source physics needed for reaching the target parameters. Emission spectroscopy is a non-invasive tool enabling access to line-of-sight averaged values of plasma parameters. This paper gives an overview of the application of emission spectroscopy in the visible range, extended for long wavelengths to the near-IR and for short wavelengths to the vacuum ultraviolet (VUV)/UV range. The amount of information to be gained from measured emission spectra is directly correlated with the effort invested for calibrating the system. Examples are given, ranging from simple monitoring to the complex evaluation of molecular spectra and the determination of highly energetic photon fluxes in the VUV/UV range. Additional emphasis is laid on the population models needed for the interpretation of measured spectra.

Drop of Solar Wind at the End of the 20th Century

AbstractVariations in the solar wind (SW) parameters with scales of several years are an important characteristic of solar activity and the basis for a long‐term space weather forecast. We examine the behavior of interplanetary parameters over 21–24 solar cycles (SCs) on the basis of the OMNI database (https://spdf.gsfc.nasa.gov/pub/data/omni). Since changes in the parameters can be associated with both changes in the number of different large‐scale types of SW and with variations in the values of these parameters at different phases of the solar cycle and during the transition from one cycle to another, we select the entire study period in accordance with the Catalog of large‐scale SW types for 1976–2019 (see the site http://www.iki.rssi.ru/pub/omni, [Yermolaev, Nikolaeva, et al., 2009, https://doi.org/10.1134/s0010952509020014], which covers the period from 21 to 24 SCs) and in accordance with the phases of the cycles, and average the parameters at selected intervals. In addition to a sharp drop in the number of interplanetary coronal mass ejections and associated sheath types, there is a noticeable drop in the value (by 20%–40%) of plasma parameters and magnetic field in different types of solar wind at the end of the 20th century and a continuation of the fall or persistence at a low level in the 23–24 cycles. Such a drop in the solar wind is apparently associated with a decrease in solar activity and manifests itself in a noticeable decrease in space weather factors.

Effects of Quantum Diffraction on the Propagation of E-A-W Solitary Structure in Fermi Plasma

Plasma state of matter can be studied in various types of situations. These studies are of great interest in Astrophysical objects like galaxies, accretion disk, neutron stars, etc, and laboratory plasma as well. Different objects demand different approaches to investigate the dynamics of the plasma. The relativistic effects in the motion of electrons in Quantum Plasma highly affect the characteristics of the solitary structure of the wave with two-temperature electrons. In this paper, considering the quantum hydrodynamic (QHD) model a dispersion relation is derived, and using standard perturbation technique, a mathematical model (i.e. nonlinear Schrodinger Equation) is studied for a wave with relativistic and quantum effects in it. We study the analysis for different values of diffraction coefficient, streaming velocity, and other plasma parameters as well. We analyze the stable rogue wave structure using NLSE and run simulations of those solitary profiles and rogue waves.

Effect of the copper plasma density on the growth of SiOx-Cu thin films by PLD

Copper containing silicon oxide layers were grown by pulsed laser deposition. Silicon and copper targets were simultaneously ablated in order to combine both laser produced plasmas using a parallel configuration in an oxygen containing atmosphere at a fixed pressure of 20 mTorr. The plasmas were characterized independently using a Langmuir planar probe to calculate the mean kinetic energy and density of the silicon and copper ions. Fixed values for plasma parameters of Si were chosen while the Cu plasma density was varied from 0 to 1.7x1013 cm−3 with the aim to modify the Cu content on the films. Nanolayers of SiOx-Cu with thicknesses ranging from 50 to 110 nm were obtained. As Cu ion density increased, different Cu species (Cu and CuO) were incorporated into SiOx matrices with different Si/O atomic ratios, which were strongly affected by variations in Cu ion density.

Modulational instability of bright envelope soliton and rogue waves in ultra-relativistic degenerate dense electron-ion-positron plasma

Modulational instability and bright envelope solitons of ion acoustic waves in dense plasma consisting of ultra-relativistic degenerate electrons and positrons, cold and mobile inertial ions, and negatively charged static dust particles have been investigated using Fried and Ichikawa method. Nonlinear Schrodinger equation has been derived and the growth rate of modulationally unstable ion acoustic wave in such plasma is discussed. It has been found that ion acoustic wave will be always modulationally unstable for all possible values of density of positrons, electrons and charged dust particle but there is no instability of the wave for any value of plasma parameters in such plasma. The solutions of ion acoustic envelope- solitons and rogue waves are obtained from the Nonlinear Schrodinger equation. The theoretical results have been analyzed numerically for different values of plasma parameters and the results are presented graphically. It is found that only bright envelope soliton would be excited in the ultra-relativistic plasma. Our results are new and may be applicable for the study of nonlinear wave processes in relativistic degenerate dense plasmas of astrophysical objects, namely, in white dwarfs and neutron stars.