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.

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.

Solitary kinetic Alfvén waves in the two‐fluid model

1996 ◽  
Vol 3 (8) ◽  
pp. 2879-2884 ◽  
Author(s):  
De‐Jin Wu ◽  
Guang‐Li Huang ◽  
De‐Yu Wang ◽  
Carl‐Gunne Fälthammar
Keyword(s):  
Fluid Model ◽  
Alfven Waves ◽  
Alfvén Waves ◽  
Two Fluid Model ◽  
Two Fluid ◽  
Kinetic Alfvén Waves

scholarly journals Numerical simulations of the lower solar atmosphere heating by two-fluid nonlinear Alfvén waves

2020 ◽  
Vol 639 ◽  
pp. A45
Author(s):  
B. Kuźma ◽  
D. Wójcik ◽  
K. Murawski ◽  
D. Yuan ◽  
S. Poedts
Keyword(s):  
Magnetic Flux ◽  
Numerical Simulations ◽  
Solar Atmosphere ◽  
Flux Tube ◽  
Alfven Waves ◽  
Alfven Wave ◽  
Magnetic Flux Tube ◽  
Alfvén Waves ◽  
Two Fluid ◽  
Lower Solar Atmosphere

Context. We present new insight into the long-standing problem of plasma heating in the lower solar atmosphere in terms of collisional dissipation caused by two-fluid Alfvén waves. Aims. Using numerical simulations, we study Alfvén wave propagation and dissipation in a magnetic flux tube and their heating effect. Methods. We set up 2.5-dimensional numerical simulations with a semi-empirical model of a stratified solar atmosphere and a force-free magnetic field mimicking a magnetic flux tube. We consider a partially ionized plasma consisting of ion + electron and neutral fluids, which are coupled by ion-neutral collisions. Results. We find that Alfvén waves, which are directly generated by a monochromatic driver at the bottom of the photosphere, experience strong damping. Low-amplitude waves do not thermalize sufficient wave energy to heat the solar atmospheric plasma. However, Alfvén waves with amplitudes greater than 0.1 km s−1 drive through ponderomotive force magneto-acoustic waves in higher atmospheric layers. These waves are damped by ion-neutral collisions, and the thermal energy released in this process leads to heating of the upper photosphere and the chromosphere. Conclusions. We infer that, as a result of ion-neutral collisions, the energy carried initially by Alfvén waves is thermalized in the upper photosphere and the chromosphere, and the corresponding heating rate is large enough to compensate radiative and thermal-conduction energy losses therein.

A two-fluid solar wind model with Alfven waves: Parameter study and application to observations

1986 ◽  
Vol 91 (A3) ◽  
pp. 2950 ◽  
Author(s):  
Ruth Esser ◽  
Egil Leer ◽  
Shadia R. Habbal ◽  
George L. Withbroe
Keyword(s):  
Solar Wind ◽  
Alfven Waves ◽  
Alfvén Waves ◽  
Parameter Study ◽  
Wind Model ◽  
Solar Wind Model ◽  
Two Fluid

Kinetic Alfvén waves in an inhomogeneous anisotropic magnetoplasma in the presence of an inhomogeneous electric field: particle aspect analysis

2000 ◽  
Vol 63 (4) ◽  
pp. 311-328 ◽  
Author(s):  
A. BARONIA ◽  
M. S. TIWARI
Keyword(s):  
Growth Rate ◽  
Dispersion Relation ◽  
Electric Field ◽  
Alfven Waves ◽  
Alfven Wave ◽  
Larmor Radius ◽  
Alfvén Waves ◽  
Temperature Anisotropy ◽  
Inhomogeneous Electric Field ◽  
Kinetic Alfvén Waves

Kinetic Alfvén waves in the presence of an inhomogeneous electric field applied perpendicular to the ambient magnetic field in an anisotropic, inhomogeneous magnetoplasma are investigated. The particle aspect approach is adopted to investigate the trajectories of charged particles in the electromagnetic field of a kinetic Alfvén wave. Expressions are found for the field-aligned current, the perpendicular current, the dispersion relation and the particle energies. The growth rate of the wave is obtained by an energy- conservation method. It is predicted that plasma density inhomogeneity is the main source of instability, and an enhancement of the growth rate by electric field inhomogeneity and temperature anisotropy is found. The dispersion relation and growth rate involve the finite-Larmor-radius effect, electron inertia and the temperature anisotropy of the magnetoplasma. The applicability of the investigation to the auroral acceleration region is discussed.

Electromagnetic ion-cyclotron instability in low beta plasma with intrinsic Alfven waves

2021 ◽  
Author(s):  
GuanShan Pu ◽  
ChuanBing Wang ◽  
PeiJin Zhang ◽  
Lin Ye
Keyword(s):  
Growth Rate ◽  
Low Frequency ◽  
Alfven Waves ◽  
Qualitative Description ◽  
Alfvén Waves ◽  
Temperature Anisotropy ◽  
Dimensional Parameter ◽  
Positive Effects ◽  
Ion Cyclotron ◽  
Emic Waves

<p>Intrinsic Alfven waves (IAWs) exist pervasively in the solar-terrestrial plasma, which can preferentially heat newborn ions in the direction perpendicular to the ambient magnetic field via non-resonant interactions when the plasma beta is low. The anisotropized newborn ion populations can excite electromagnetic ion-cyclotron (EMIC) instability. Parametric calculations indicate that the lower the plasma beta is, the higher the growth rate, while the growth rate increases with the number density of newborn ions and the intensity of IAWs. The marginal stable surface in three-dimensional parameter space is also calculated, which provides a qualitative description of parametric conditions for instability. We propose that the coupled effects of non-resonant heating by IAWs and EMIC instability could be an effective mechanism for transferring the energy from low-frequency IAWs to EMIC waves with a frequency below the gyrofrequency of the corresponding ion species. Furthermore, the temperature anisotropy of background ions with the same sense has positive effects on the growth of EMIC waves excited by newborn ions.</p>

Acceleration and heating of two-fluid solar wind by Alfven waves

1994 ◽  
Vol 423 ◽  
pp. 500 ◽  
Author(s):  
Ornulf Sandbaek ◽  
Egil Leer
Keyword(s):  
Solar Wind ◽  
Alfven Waves ◽  
Alfvén Waves ◽  
Two Fluid

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 Possible role of magnetosphere-ionosphere coupling in auroral arc generation

2000 ◽  
Vol 18 (9) ◽  
pp. 1108-1117 ◽  
Author(s):  
W. Lyatsky ◽  
A. M. Hamza
Keyword(s):  
Growth Rate ◽  
Plasma Sheet ◽  
Alfven Waves ◽  
The Other ◽  
Alfven Wave ◽  
Alfvén Waves ◽  
Ionospheric Conductivity ◽  
Model Based ◽  
Field Aligned Current ◽  
Auroral Arcs

Abstract. Three models for the magnetosphere-ionosphere coupling feedback instability are considered. The first model is based on demagnetization of hot ions in the plasma sheet. The instability takes place in the global magnetosphere-ionosphere system when magnetospheric electrons drift through a spatial gradient of hot magnetospheric ion population. Such a situation exists on the inner and outer edges of the plasma sheet where relatively cold magnetospheric electrons move earthward through a radial gradient of hot ions. This leads to the formation of field-aligned currents. The effect of upward field-aligned current on particle precipitation and the magnitude of ionospheric conductivity leads to the instability of this earthward convection and to its division into convection streams oriented at some angle with respect to the initial convection direction. The growth rate of the instability is maximum for structures with sizes less than the ion Larmor radius in the equatorial plane. This may lead to formation of auroral arcs with widths about 10 km. This instability explains many features of such arcs, including their conjugacy in opposite hemispheres. However, it cannot explain the very high growth rates of some auroral arcs and very narrow arcs. For such arcs another type of instability must be considered. In the other two models the instability arises because of the generation of Alfven waves from growing arc-like structures in the ionospheric conductivity. One model is based on the modulation of precipitating electrons by field-aligned currents of the upward moving Alfven wave. The other model takes into consideration the reflection of Alfven waves from a maximum in the Alfven velocity at an altitude of about 3000 km. The growth of structures in both models takes place when the ionization function associated with upward field-aligned current is shifted from the edges of enhanced conductivity structures toward their centers. Such a shift arises because the structures move at a velocity different from the E×B drift. Although both models may work, the growth rate for the model, based on the modulation of the precipitating accelerated electrons, is significantly larger than that of the model based on the Alfven wave reflection. This mechanism is suitable for generation of auroral arcs with widths of about 1 km and less. The growth rate of the instability can be as large as 1 s-1, and this mechanism enables us to justify the development of auroral arcs only in one ionosphere. It is hardly suitable for excitation of wide and conjugate auroral arcs, but it may be responsible for the formation of small-scale structures inside a wide arc.Key words: Ionosphere (auroral ionosphere) - Magnetospheric physics (auroral phenomena; magnetosphere-ionosphere interactions)  

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