scholarly journals STABILITY OF ALFVEN WINGS IN HMHD

Anales AFA ◽  
2021 ◽  
Vol 32 (1) ◽  
pp. 1-6
Author(s):  
P. A. Sallago ◽  
Keyword(s):  
Solar System ◽  
Analytical Method ◽  
Alfven Waves ◽  
Magnetized Plasma ◽  
Alfvén Waves ◽  
Magnetized Plasmas ◽  
Ohm’S Law ◽  
Electronic Pressure ◽  
Solar System Bodies ◽  
The Stability

A conducting source moving uniformly through a magnetized plasma generates, among a variety of perturbations,Alfvén waves. Alfvén waves can build up structures in the plasma called Alfvén wings. The wings have been detec-ted and measured in many solar system bodies, and their existence have been theoretically proved also. Under certainconditions, Hall and electronic pressure must be taken into account in the Ohm’s law and so one gets Hall Magne-tohydrodynamics (HMHD). In spite of Sallago and Platzeck have shown the existence of Alfvén wings in HMHD, theirstability under such conditions remains to be studied. The aim of this paper is to analyze the stability of an Alfvén wing,in the presence of an incompressible perturbation that has the same symmetry than the structure and polarization, inHMHD. Palumbo has developed an analytical method for the study of the stability of static structures with a symmetryin magnetized plasmas, in the presence of incompressible perturbations with the same symmetry than the structure.Since Alfvén wings are stationary structures, Sallago and Platzeck have shown the stability of such Alfvén wings in MHD conditions by extending Palumbo’s method. In the present paper this method is extended for Alfvén wings in HMHD conditions, and one concludes that in the presence of this kind of perturbations they are stable.

Stability of Alfvén wings in uniform plasmas

2007 ◽  
Vol 73 (6) ◽  
pp. 957-966
Author(s):  
P. A. SALLAGO ◽  
A. M. PLATZECK
Keyword(s):  
Solar System ◽  
Normal Modes ◽  
Background Field ◽  
Alfven Waves ◽  
Magnetized Plasma ◽  
Alfvén Waves ◽  
Solar System Bodies ◽  
Uniform Background ◽  
The Stability ◽  
Magnetohydrodynamic System

AbstractA conducting source moving uniformly through a magnetized plasma generates, among a variety of perturbations, Alfvén waves. An interesting characteristic of Alfvén waves is that they can build up structures in the plasma called Alfvén wings. These wings have been detected and measured in many solar system bodies, and their existence has also been theoretically proven. However, their stability remains to be studied. The aim of this paper is to analyze the stability of an Alfvén wing developed in a uniform background field, in the presence of an incompressible perturbation that has the same symmetry as the Alfvén wing, in the magnetohydrodynamic approximation. The study of the stability of a magnetohydrodynamic system is often performed by linearizing the equations and using either the normal modes method or the energy method. In spite of being applicable for many problems, both methods become algebraically complicated if the structure under analysis is a highly non-uniform one. Palumbo has developed an analytical method for the study of the stability of static structures with a symmetry in magnetized plasmas, in the presence of incompressible perturbations with the same symmetry as the structure (Palumbo 1998 Thesis, Universidad de Firenze, Italia). In the present paper we extend this method for Alfvén wings that are stationary structures, and conclude that in the presence of this kind of perturbation they are stable.

Three-dimensional stability of solitary shear kinetic Alfvén waves in a low-beta plasma

1989 ◽  
Vol 41 (1) ◽  
pp. 171-184 ◽  
Author(s):  
K. P. Das ◽  
L. P. J. Kamp ◽  
F. W. Sluijter
Keyword(s):  
Growth Rate ◽  
Dimensional Stability ◽  
Three Dimensional ◽  
Alfven Waves ◽  
Magnetized Plasma ◽  
Alfvén Waves ◽  
Ion Acoustic Solitons ◽  
The Stability ◽  
External Uniform Magnetic Field ◽  
Kinetic Alfvén Waves

The three-dimensional stability of solitary shear kinetic Alfvén waves in a low-β plasma is investigated by the method of Zakharov & Rubenchik (1974). It is found that there is no instability if the direction of perturbation falls within a certain region of space. The growth rate of the instability for the unstable region is determined. This growth rate is found to decrease with increasing angle between the direction of propagation of the solitary wave and the direction of the external uniform magnetic field. A particular case of the present analysis gives results on the stability of ion-acoustic solitons in a magnetized plasma.

scholarly journals Prebiotic Matter in Space

2012 ◽  
Vol 10 (H16) ◽  
pp. 709-710
Author(s):  
Pascale Ehrenfreund ◽  
Andreas Elsaesser ◽  
J. Groen
Keyword(s):  
Solar System ◽  
Carbonaceous Material ◽  
Early Earth ◽  
Solar System Bodies ◽  
Space Environments ◽  
The Stability ◽  
Extraterrestrial Material

AbstractA significant number of molecules that are used in contemporary biochemistry on Earth are found in interstellar and circumstellar regions as well as solar system environments. In particular small solar system bodies hold clues to processes that formed our solar system. Comets, asteroids, and meteorite delivered extraterrestrial material during the heavy bombardment phase ~3.9 billion years ago to the young planets, a process that made carbonaceous material available to the early Earth. In-depth understanding of the organic reservoir in different space environments as well as data on the stability of organic and prebiotic material in solar system environments are vital to assess and quantify the extraterrestrial contribution of prebiotic sources available to the young Earth.

Nonlinear interection of alfven waves and ionic acoustic waves in a magnetized plasma

1996 ◽  
Vol 2 (3-4) ◽  
pp. 44-48
Author(s):  
A.K. Yukhimuk ◽  
◽  
O.G. Fal'ko ◽  
V.A. Yukhimuk ◽  
V.P. Kucherenko ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Alfven Waves ◽  
Magnetized Plasma ◽  
Alfvén Waves

scholarly journals Viscoelastic type magnetic effects and self-gravity on the propagation of MHD waves

Meccanica ◽  
2020 ◽  
Vol 55 (11) ◽  
pp. 2199-2214
Author(s):  
Franca Franchi ◽  
Barbara Lazzari ◽  
Roberta Nibbi
Keyword(s):  
Alfven Waves ◽  
Accelerated Expansion ◽  
Mhd Waves ◽  
Critical Threshold ◽  
Alfvén Waves ◽  
Sonic Waves ◽  
The Stability ◽  
Definition Of ◽  
Self Gravity ◽  
Network Patterns

Abstract We take up the challenge to explain the correlation between the Jeans instability topic towards star formation within the accelerated expansion of universe and the role of torsional shear-like Alfven waves in triggering the formation of network patterns, by proposing new mathematical models for self-gravitating interstellar non ideal MHD plasmas. The diffusion of the gravitational field is included via a parabolic Einstein’s equation with the cosmological constant, whereas anomalous resistive features are described through non ideal Ohm’s laws incorporating inertia terms, to account of relaxation and retardation magnetic responses. We perform a spectral analysis to test the stability properties of the novel constitutive settings where dissipative and elastic devices act together, by emphasizing the differences with previous models. As a main result, we highlight the definition of a lower critical threshold, here called the Jeans-Einstein wavenumber, against collapse formation towards the formation of longitudinal gravito-magneto-sonic waves and transverse non gravitational Alfven waves exhibiting larger effective wavespeeds, due to the hyperbolic-parabolic diffusion of the magnetic field. Consequently shorter collisional times are allowable so, beyond the plasma-beta, another interesting key point is the definition of the Ohm number to revisit the timescale topic, towards reviewed Reynolds and Lundquist numbers able to better capture the microphysical phenomena of Magnetic Reconnection in narrow diffusion regimes.

The Stability of the Relativistic Alfvén Waves

1983 ◽  
Vol 23 (2) ◽  
pp. 117-132
Author(s):  
C. D. Ciubotariu ◽  
D. I. Zoler ◽  
N. S. Thirer
Keyword(s):  
Alfven Waves ◽  
Alfvén Waves ◽  
The Stability

The growth of Alfvén waves in the resistive current-driven instability

1997 ◽  
Vol 58 (3) ◽  
pp. 433-440 ◽  
Author(s):  
GUANG-LI HUANG ◽  
REN-YING WANG
Keyword(s):  
Growth Rate ◽  
Electric Current ◽  
Alfven Waves ◽  
Magnetized Plasma ◽  
Alfvén Waves ◽  
Tearing Mode ◽  
Stability Calculation ◽  
Electrons And Ions ◽  
Linear Friction ◽  
Two Fluid

On the basis of a two-fluid, cold-plasma, linear stability calculation with linear friction between electrons and ions, the growth rate of Alfvén waves is derived from the dispersion relation for a uniformly magnetized plasma, in which the plasma resistivity and a uniform electric current carried by an electron beam are both considered. The growth rate is directly proportional to the plasma resistivity, the electric current density and the value of the parameter ωxpe/Ωe (where ωxpe and Ωe are the electron plasma and cyclotron frequency respectively). Moreover, the growth of Alfvén waves is mainly excited in a direction nearly parallel to the ambient magnetic field. The critical value of the velocity of the electron fluid is just equal to the Alfvén velocity. The results of this paper are compared with those for the linear tearing mode.

scholarly journals Controlling the type and intensity of low-frequency waves generated by laser plasma clots in a force tube of magnetized plasma

2021 ◽  
Vol 2067 (1) ◽  
pp. 012019
Author(s):  
A G Berezutsky ◽  
V N Tishchenko ◽  
A A Chibranov ◽  
I B Miroshnichenko ◽  
Yu P Zakharov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Laser Plasma ◽  
Low Frequency ◽  
Alfven Waves ◽  
Magnetized Plasma ◽  
Background Plasma ◽  
Alfvén Waves ◽  
Whistler Waves ◽  
Low Frequency Waves

Abstract In this work, we study the influence of the parameters of a magnetized background plasma on the intensity of whistler waves generated by periodic laser plasma bunches in a magnetic field tube. It is shown that at 0.3 < Lpi > 0.4 Alfvén waves and whistlers are generated. In the region Lpi> 0.5, intense whistlers with an amplitude of δBmax / B0 ∼ 0.24 are generated.

Parametric excitation of upper hybrid and kinetic alfven waves in a magnetized plasma

1998 ◽  
Vol 4 (1) ◽  
pp. 108-112 ◽  
Author(s):  
A.K. Yukhimuk ◽  
◽  
V.N. Fedun ◽  
V.A. Yukhimuk ◽  
V.N. Ivchenko ◽  
...  
Keyword(s):  
Parametric Excitation ◽  
Alfven Waves ◽  
Magnetized Plasma ◽  
Alfvén Waves ◽  
Kinetic Alfvén Waves
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