scholarly journals Generation of Low-Frequency Kinetic Waves at the Footpoints of Pre-Flare Coronal Loops

Solar Physics ◽  
2020 ◽  
Vol 295 (12) ◽  
Author(s):  
Alexandr Kryshtal ◽  
Anna Voitsekhovska ◽  
Oleg Cheremnykh ◽  
Istvan Ballai ◽  
Gary Verth ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Low Frequency ◽  
Small Scale ◽  
Plasma Parameters ◽  
Ion Acoustic Waves ◽  
Frequency Wave ◽  
Electric And Magnetic Fields ◽  
Ion Acoustic ◽  
Flare Process ◽  
Semi Empirical

AbstractIn this study we discuss the excitation of low-frequency plasma waves in the lower-middle chromosphere region of loop footpoints for the case when the plasma can be considered to be in a pre-flare state. It is shown that among the well-known semi-empirical models of the solar atmosphere, only the VAL (F) model together with a particular set of basic plasma parameters and amplitudes of the electric and magnetic fields supports generation of low-frequency wave instability. Our results show that it is possible to predict the onset of the flare process in the active region by using the interaction of kinetic Alfvén and kinetic ion-acoustic waves, which are solutions of the derived dispersion equation. The VAL (F) model allows situations when the main source of the aforementioned instability can be a sub-Dreicer electric field and drift plasma movements due to presence of spatial inhomogeneities. We also show that the generation of kinetic Alfvén and kinetic ion-acoustic waves can occur both, in plasma with a purely Coulomb conductivity and in the presence of small-scale Bernstein turbulence. The excitation of the small amplitude kinetic waves due to the development of low threshold instability in plasma with relatively low values of the magnetic field strength is also discussed.

scholarly journals Effects of Boundary and Electron Inertia on the Ion Acoustic Wave in a Plasma: A Pseudopotential Approach

1998 ◽  
Vol 51 (1) ◽  
pp. 113 ◽  
Author(s):  
K. K. Mondal ◽  
S. N. Paul ◽  
A. Roy Chowdhury
Keyword(s):  
Acoustic Waves ◽  
Finite Geometry ◽  
Cylindrical Domain ◽  
Plasma Parameters ◽  
Ion Acoustic Waves ◽  
Ion Acoustic Wave ◽  
Electron Inertia ◽  
Ion Acoustic ◽  
Pseudopotential Approach ◽  
Range Of Values

A pseudopotential approach is used to analyse the propagation of ion-acoustic waves in a plasma bounded by a cylindrical domain. The effect of the finite geometry is displayed both analytically and numerically. The phase velocity of the wave is determined and its variation is studied with respect to the plasma parameters. It is observed that the pseudopotential shows a wide variation of shape due to the imposition of a finite boundary condition. It is shown that if the other parameters are kept within a certain range of values, then the trapping of particles is favoured when the presence of the boundary is taken into account.

Ion acoustic waves in expanding strongly coupled plasmas

2013 ◽  
Vol 79 (6) ◽  
pp. 1063-1066 ◽  
Author(s):  
J. T. MENDONÇA ◽  
N. SHUKLA ◽  
D. P. RESENDES ◽  
A. SERBETO
Keyword(s):  
Acoustic Waves ◽  
Temporal Change ◽  
Wave Mode ◽  
Mode Structure ◽  
Plasma Parameters ◽  
Ion Acoustic Waves ◽  
Strongly Coupled ◽  
Ultracold Plasmas ◽  
Ion Acoustic ◽  
Coupled Plasmas

AbstractWe consider the excitation and dispersion of ion acoustic waves in expanding ultracold plasmas, taking into account the influence of boundary conditions. A cylindrical plasma geometry is assumed. We show that temporal changes in the medium lead to a wave frequency shift, associated with an evolving radial and standing wave mode structure, and to the temporal change of the background plasma parameters. A non-collisional model for the cylindrical geometry is also proposed.

Numerical simulations of Zakharov’s (ZK) non-dimensional equation arising in Langmuir and ion-acoustic waves

2021 ◽  
pp. 2150480
Author(s):  
Mostafa M. A. Khater
Keyword(s):  
Acoustic Waves ◽  
Electromagnetic Waves ◽  
Low Frequency ◽  
Expansion Method ◽  
Ion Acoustic Waves ◽  
B Spline ◽  
Kudryashov Method ◽  
Ion Acoustic ◽  
Dimensional Equation ◽  
The Relationship

The trigonometric quintic B-spline scheme is used in this research paper to research Zakharov’s (ZK) nonlinear dimensional equation’s numerical solution. The ZK model’s solutions explain the relationship between the high-frequency Langmuir and the low-frequency ion-acoustic waves with many applications in optical fiber, coastal engineering, and fluid mechanics of electromagnetic waves, plasma physics, and signal processing. Three recent computational schemes (the expanded [Formula: see text]-expansion method, generalized Kudryashov method, and modified Khater method) have recently been used to investigate this model’s moving wave solution. Many innovative solutions have been established in this paper to determine the original and boundary conditions that allow numerous numerical schemes to be implemented. Here, the trigonometric quintic B-spline method is used to analyze the precision of the collected analytical solutions. To illustrate the precision of the numerical and computational solutions, distinct drawings are depicted.

Nonlinear propagation of ion-acoustic waves and low-frequency electrostatic modes in a dusty plasma

1993 ◽  
Vol 50 (1) ◽  
pp. 37-44 ◽  
Author(s):  
U. A. Mofiz ◽  
Madhabi Islam ◽  
Zarin Ahmed
Keyword(s):  
Dusty Plasma ◽  
Acoustic Waves ◽  
Wave Scattering ◽  
Evolution Equations ◽  
Low Frequency ◽  
Nonlinear Propagation ◽  
Ion Acoustic Waves ◽  
Ion Acoustic ◽  
Ion Acoustic Solitons

Nonlinear propagation of ion-acoustic waves and low-frequency electrostatic modes in a dusty plasma is investigated. The evolution equations of these modes are developed and solved analytically. It is found that for small grain charge usual ion-acoustic solitons may exist in a dusty plasma, but increasing grain charge destroys them and finally they may disappear. The low-frequency electrostatic mode may be localized, forming solitons, which may act as centres of wave scattering in a dusty plasma.

scholarly journals Nonlinear Waveforms for Ion-Acoustic Waves in Weakly Relativistic Plasma of Warm Ion-Fluid and Isothermal Electrons

2012 ◽  
Vol 2012 ◽  
pp. 1-12
Author(s):  
S. A. El-Wakil ◽  
Essam M. Abulwafa ◽  
E. K. El-Shewy ◽  
H. G. Abdelwahed ◽  
Hamdi M. Abd-El-Hamid
Keyword(s):  
Acoustic Waves ◽  
Kdv Equation ◽  
Algebraic Method ◽  
Finite Amplitude ◽  
Reductive Perturbation Method ◽  
Relativistic Plasma ◽  
Plasma Parameters ◽  
Ion Acoustic Waves ◽  
Ion Acoustic ◽  
Weakly Relativistic Plasma

The reductive perturbation method has been employed to derive the Korteweg-de Vries (KdV) equation for small- but finite-amplitude electrostatic ion-acoustic waves in weakly relativistic plasma consisting of warm ions and isothermal electrons. An algebraic method with computerized symbolic computation is applied in obtaining a series of exact solutions of the KdV equation. Numerical studies have been made using plasma parameters which reveal different solutions, that is, bell-shaped solitary pulses, rational pulses, and solutions with singularity at finite points, which called “blowup” solutions in addition to the propagation of an explosive pulses. The weakly relativistic effect is found to significantly change the basic properties (namely, the amplitude and the width) of the ion-acoustic waves. The result of the present investigation may be applicable to some plasma environments, such as ionosphere region.

scholarly journals Modulational Instability of Ion-Acoustic Waves in Pair-Ion Plasma

Plasma ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 1-11
Author(s):  
Sharmin Jahan ◽  
Rubaiya Khondoker Shikha ◽  
Abdul Mannan ◽  
A A Mamun
Keyword(s):  
Acoustic Waves ◽  
Modulational Instability ◽  
Thermal Parameter ◽  
Reductive Perturbation Method ◽  
Unstable State ◽  
Plasma Parameters ◽  
Ion Acoustic Waves ◽  
Stable Domain ◽  
Ion Acoustic ◽  
Component Plasma

The modulational instability (MI) of ion-acoustic waves (IAWs) is examined theoretically in a four-component plasma system containing inertialess electrons featuring a non-thermal, non-extensive distribution, iso-thermal positrons, and positively as well as negatively charged inertial ions. In this connection, a non-linear Schrödinger equation (NLSE), which dominates the conditions for MI associated with IAWs, is obtained by using the reductive perturbation method. The numerical analysis of the NLSE reveals that the increment in non-thermality leads to a more unstable state, whereas the enhancement in non-extensivity introduces a less unstable state. It also signifies the bright (dark) ion-acoustic (IA) envelope solitons mode in the unstable (stable) domain. The conditions for MI and its growth rate in the unstable regime of the IAWs are vigorously modified by the different plasma parameters (viz., non-thermal, non-extensive q-distributed electron, iso-thermal positron, the ion charge state, the mass of the ion and positron, non-thermal parameter α, the temperature of electron and positron, etc.). Our findings may supplement and add to prior research in non-thermal, non-extensive electrons and iso-thermal positrons that can co-exist with positive as well as negative inertial ions.

scholarly journals Nonlinear propagation of ion acoustic waves in quantum plasma in the presence of an ion beam

2019 ◽  
Vol 37 (4) ◽  
pp. 370-380 ◽  
Author(s):  
Indrani Paul ◽  
Arkojyothi Chatterjee ◽  
Sailendra Nath Paul
Keyword(s):  
Solitary Waves ◽  
Acoustic Waves ◽  
Ion Beam ◽  
Perturbation Technique ◽  
Nonlinear Propagation ◽  
Quantum Plasma ◽  
Plasma Parameters ◽  
Ion Acoustic Waves ◽  
Quantum Hydrodynamic Model ◽  
Ion Acoustic

AbstractNonlinear propagation of ion acoustic waves has been studied in unmagnetized quantum (degenerate) plasma in the presence of an ion beam using the one-dimensional quantum hydrodynamic model. The Korteweg–de Vries (K–dV) equation has been derived by using the reductive perturbation technique. The solution of ion acoustic solitary waves is obtained from the K–dV equation. The theoretical results have been analyzed numerically for different values of plasma parameters and the results are presented graphically. It is seen that the formation and structure of solitary waves are significantly affected by the ion beam in quantum plasma. The solitary waves will be compressive or rarefactive depending upon the values of velocity, concentration, and temperature of the ion beam. The critical value of ion beam density for the nonexistence of solitary wave has been numerically estimated, and its variation with velocity and temperature of ion beam has been discussed graphically. The results are new and would be very useful for understanding the beam–plasma interactions and the formation of nonlinear wave structures in dense quantum plasma.

Large amplitude ion-acoustic waves observed in the solar wind by the Solar Orbiter

2021 ◽  
Author(s):  
David Pisa ◽  
Jan Soucek ◽  
Ondrej Santolik ◽  
Milan Maksimovic ◽  
Timothy Horbury ◽  
...  
Keyword(s):  
Solar Wind ◽  
Detailed Analysis ◽  
Acoustic Waves ◽  
Large Scale ◽  
Low Frequency ◽  
Linear Wave ◽  
Ion Acoustic Waves ◽  
Ion Acoustic ◽  
The Time Domain ◽  
Low Frequency Waves

<p>Electric field observations of the Time Domain Sampler (TDS) receiver, a part of the Radio and Plasma Waves (RPW) instrument onboard Solar Orbiter, often exhibit very intense broadband emissions at frequencies below 10 kHz in the spacecraft frame. The RPW instrument has been operating almost continuously during the commissioning phase of the mission from March to May, the first perihelion in June, and through the first flyby of Venus in late December 2020. Nearly a year of observations allow us to perform a statistical study of ion-acoustic waves in the solar wind covering an interval of heliocentric distances between 0.5 AU to 1 AU. The occurrence of low-frequency waves peaks around perihelion in June at distances of 0.5 AU and decreases with increasing distances, with only a few waves detected per day in late September at ~1 AU. A more detailed analysis of triggered waveform snapshots shows the typical wave frequency at about 3 kHz and wave power about 5e-2 mV<sup>2</sup>/m<sup>2</sup>. The distribution of the relative phase between two components of the projected E-field in the Spacecraft Reference Frame (SRF) shows a mostly linear wave polarization. These waves are interpreted as strongly Doppler-shifted ion-acoustic waves, generated by solar wind ion beams and often accompany large-scale solar wind structures. A detailed analysis of the Doppler-shift using solar wind data from a Proton and Alpha particle Sensor (PAS), a part of Solar Wind Analyzer (SWA), is done for several examples.</p>

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