Field In Cold Plasma Research Articles

Double-pole solutions in the modified nonlinear Schrödinger equation

This paper is concerned with the modified nonlinear Schrödinger equation with zero boundary condition or non-zero boundary condition, which models Alfvén wave propagating along a magnetic field in cold plasmas. We are interested in the double-pole solutions that are a kind of bound-state solitons. By solving a direct scattering problem, the Jost eigenfunctions and scattering matrix are given, their symmetries and asymptotic behaviors are also presented. Then the inverse scattering problems are solved in terms of the matrix Riemann–Hilbert method. In addition, the trace formulae for analytic scattering coefficients and theta conditions are derived. Finally, the explicit formulae of double-pole solutions for the equation are obtained.

APPJ Discharge Effects on Human Factor VIII:Ag Level in Healthy and Hemophilia A Patient

Many studies in the field of cold plasma and its application in medicine and biology have been done recently. Some of them reported that cold atmospheric pressure plasma jet (APPJ) discharge accelerates blood clotting because factor VIII (FVIII) is a plasma glycoprotein that may play a role in the coagulation cascade. In this study, we aim to assess the effect of APPJ discharge on factor VIII antigen (FVIII:Ag) in healthy and hemophilic patients. Therefore, the variations of FVIII:Ag in healthy plasma samples and hemophilic plasma samples at the times of 0, 4, 8 and 16 s treatment with APPJ were measured by ELISA technique. Additionally, activated partial thromboplastin time (APTT) test was used to check the blood coagulation rate at different treatment times. Our findings showed that the amount of FVIII:Ag in healthy samples was high to low in seconds 4 > 8 > 16 > 0. The APTT results showed that APPJ increases the blood clot formation, but in hemophilic plasma samples, APPJ reduces the clot formation speed and FVIII:Ag concentration. Accordingly, the APPJ discharge elicited a slight increase in FVIII:Ag concentration in short-term treatment, which could be involved in blood coagulation. Moreover, the effects of APPJ discharge on other coagulation factors need further studies.

Analysis of the Spatial Nonuniformity of the Electric Field in Spectroscopic Diagnostic Methods of Atmospheric Electricity Phenomena.

The spatial nonuniformity of the electric field in air discharges, such as streamers, can influence the accuracy of spectroscopic diagnostic methods and hence the estimation of the peak electric field. In this work, we use a self‐consistent streamer discharge model to investigate the spatial nonuniformity in streamer heads and streamer glows. We focus our analysis on air discharges at atmospheric pressure and at the low pressure of the mesosphere. This approach is useful to investigate the spatial nonuniformity of laboratory discharges as well as sprite streamers and blue jet streamers, two types of transient luminous events taking place above thunderclouds. This characterization of the spatial nonuniformity of the electric field in air discharges allows us to develop two different spectroscopic diagnostic methods to estimate the peak electric field in cold plasmas. The commonly employed method to derive the peak electric field in streamer heads underestimates the electric field by about 40–50% as a consequence of the high spatial nonuniformity of the electric field. Our diagnostic methods reduce this underestimation to about 10–20%. However, our methods are less accurate than previous methods for streamer glows, where the electric field is uniformly distributed in space. Finally, we apply our diagnostic methods to the measured optical signals in the second positive system of N2 and the first negative system of N2+ of sprites recorded by Armstrong et al. (1998, https://doi.org/10.1016/S1364-6826(98)00026-1) during the SPRITE's 1995 and 1996 campaigns.

KDV limit of the hydromagnetic waves in cold plasma

In this paper, we study the long wavelength limit for the hydromagnetic waves propagating across a magnetic field in cold plasma. Based on the Gardner–Morikawa transform and the reductive perturbation method, it is demonstrated that as $$\varepsilon \rightarrow 0$$ , the solutions of such hydromagnetic waves converge to the solution of the Korteweg–de Vries equation on an $$O(\varepsilon ^{-3/2})$$ time interval.

Sharp threshold of global existence for the generalized Zakharov system with three-dimensional magnetic field in the subsonic limit

The paper is concerned with the Zakharov system with three dimensional magnetic field in the subsonic limit, which describes the spontaneous generation of a magnetic field in cold plasma. In fact, we will investigate the effect of the magnetic field term on the equations. By using variational calculus, we obtain the threshold of global existence and blowup of the solution to the equations, which will be more complicated and requires more skill.

Envelope Solitons for Nonlinear Alfvén Waves Propagating along along the Magnetic Field in Plasmas

The numerical computations are done to study the envelope soliton propagation behavior for the nonlinear Alfvén waves propagating along the magnetic field in cold plasmas. It is confirmed that the four Korteweg-de Vries (KdV) types of envelope solitons can propagate stably through the interactions. It is also found that the different type solitons interact each other almost linearly though the same type solitons interact each other nonlinearly.

A Perturbation Method and Its Application to Obliquely Propagating Nonlinear Alfvén Wave

A procedure to the coordinate stretching and the perturbation expansion for the reductive perturbation method is proposed to analyze the nonlinear wave behaviors in dispersive medium. The method is applied to the nonlinear Alfven wave propagating in an oblique direction to the static magnetic field in cold plasmas. Although the wave is described by a linear equation for some physical quantities, the nonlinearity appears in the relation among the other quantities for considerably large amplitude. These outstanding features are much different from other waves in plasmas.

Modified Nonlinear Schrödinger Equation for Alfvén Waves Propagating along the Magnetic Field in Cold Plasmas

The basic nonlinear equation which describes the Alfven waves, with small but finite amplitude propagating along the magnetic field in cold plasmas, is derived modifying the reductive perturbation method proposed by Taniuti and Wei. Then as a result, the nonlinear dispersion relation is obtained through a procedure which clarifies the physical meaning. Furthermore, the modified nonlinear Schrodinger equation which describes the modulated Alfven wave more correctly than the previous works is proposed. An example of the nonlinear phenomena is shown by the numerical calculations of the initial value problem, using our basic equation for the Alfven waves.

Excitation of Quasicylindrical Waves Connected with Electron Bernstein Modes

By measuring the potential around a point-source antenna in a high-density magnetoplasma at a frequency between the electron gyrofrequency and the plasma frequency, we have detected an interference between a slow electrostatic wave and the cold plasma field. A model of quasicylindrical electrostatic waves connected with the Bernstein mode is proposed to explain the results.

Electron density and temperature measurements in the lower ionosphere as deduced from the warm plasma theory of the h.f. quadrupole probe

The frequency response of the h.f. quadrupole probe is calculated to be used as a diagnostic tool for measurements of electron density and temperature. In §2 the magnetic field is assumed to be zero, and ion motions are neglected. For a Maxwellian plasma, the so-called ‘Landau wave approximation’ is compared with various more sophisticated treatments, such as numerical integration or super-Cauchy and multiple water-bag models. The range of validity of this approximation is shown to be large, and the results can be applied to the most interesting parts of the experimental observations. All results previously established are recovered with greater speed. Having studied various disturbances (collisions, inhomogeneity and relative motion of the probe with respect to the plasma), it is deduced that the best way to determine the electron temperature is to use the anti-resonances due to beating between the Landau wave and the cold plasma field. In § 3 we describe the quadrupole probe, launched in December 1971 as part of the CISASPE rocket experiment. To deduce the electron density and temperature from these measurements, it is necessary to consider the influence of a static magnetic field, such as the earth's magnetic field. The general case could be treated by numerical integration, though with great difficulty, but it is shown that in most ionospheric conditions, in the vicinity of the upper hybrid frequency ωT the above treatment is again possible, the plasma frequency simply being replaced by ωT, and the thermal velocity slightly modified. These assumptions are used to deduce the electron density and temperature profiles.