scholarly journals Influence of plasma inhomogeneity with allowance for bremsstrahlung on absorption of an Alfvén wave by a dissipative plasma

2021 ◽  
pp. 1-16
Author(s):  
Aleksei Aleksandrovich Tayurskiy
Keyword(s):  
Penetration Depth ◽  
Inhomogeneous Plasma ◽  
Stationary Regime ◽  
Alfven Wave ◽  
Depth Of Penetration ◽  
Plasma Inhomogeneity ◽  
Electrons And Ions ◽  
Density Inhomogeneities ◽  
Maximum Temperatures ◽  
Two Fluid

The paper investigates a mathematical model of the absorption of an Alfvén wave in an inhomogeneous incompressible dissipative plasma using the equations of two-fluid electromagnetic hydrodynamics. It is shown that a consequence of taking into account bremsstrahlung is the finiteness of the penetration depth of the Alfvén wave into an inhomogeneous plasma and a steady quasi-stationary regime of the Alfvén wave absorption. Density inhomogeneities of two types are considered – hump and hollows, which are distributed according to the Gaussian law. The dependences on the value of the hump of the penetration depth of the Alfvén wave into the inhomogeneous plasma and the maximum temperatures of electrons and ions are obtained. The study showed that an increase in the amplitude of the incident wave leads to an increase in the maximum values of the electron and ion temperatures, as well as the depth of penetration of the Alfvén wave into an inhomogeneous dissipative plasma.

scholarly journals Spatial structure and dispersion of drift mirror waves coupled with Alfvén waves in a 1-D inhomogeneous plasma

2006 ◽  
Vol 24 (8) ◽  
pp. 2291-2297 ◽  
Author(s):  
D. Yu. Klimushkin
Keyword(s):  
Growth Rate ◽  
Spatial Structure ◽  
Inhomogeneous Plasma ◽  
Space Plasma ◽  
Radial Component ◽  
Alfven Wave ◽  
Radial Coordinate ◽  
Plasma Inhomogeneity ◽  
Azimuthal Component ◽  
Mirror Mode

Abstract. The paper employs the frame of a 1-D inhomogeneous model of space plasma,to examine the spatial structure and growth rate of drift mirror modes, often suggested for interpreting some oscillation types in space plasma. Owing to its coupling with the Alfvén mode, the drift mirror mode attains dispersion across magnetic shells (dependence of the frequency on the wave-vector's radial component, kr). The spatial structure of a mode confined across magnetic shells is studied. The scale of spatial localization of the wave is shown to be determined by the plasma inhomogeneity scale and by the azimuthal component of the wave vector. The wave propagates across magnetic shells, its amplitude modulated along the radial coordinate by the Gauss function. Coupling with the Alfvén mode strongly influences the growth rate of the drift mirror instability. The mirror mode can only exist in a narrow range of parameters. In the general case, the mode represents an Alfvén wave modified by plasma inhomogeneity.

Study of gradient effects on kinetic Alfven wave with inhomogeneous plasma

2013 ◽  
Vol 345 (1) ◽  
pp. 99-107 ◽  
Author(s):  
P. Agarwal ◽  
P. Varma ◽  
M. S. Tiwari
Keyword(s):  
Inhomogeneous Plasma ◽  
Alfven Wave ◽  
Kinetic Alfvén Wave ◽  
Kinetic Alfven Wave ◽  
Gradient Effects

scholarly journals Compressional wave events in the dawn plasma sheet observed by Interball-1

1999 ◽  
Vol 17 (9) ◽  
pp. 1145-1154 ◽  
Author(s):  
O. Verkhoglyadova ◽  
A. Agapitov ◽  
A. Andrushchenko ◽  
V. Ivchenko ◽  
S. Romanov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Time Series ◽  
Field Line ◽  
Plasma Sheet ◽  
Inhomogeneous Plasma ◽  
Partial Solution ◽  
Alfven Wave ◽  
Data Set ◽  
Background Magnetic Field ◽  
Phase Variations

Abstract. Compressional waves with periods greater than 2 min (about 10-30 min) at low geomagnetic latitudes, namely compressional Pc5 waves, are studied. The data set obtained with magnetometer MIF-M and plasma analyzer instrument CORALL on board the Interball-1 are analyzed. Measurements performed in October 1995 and October 1996 in the dawn plasma sheet at -30 RE ≤ XGSM and |ZGSM| ≤ 10 RE are considered. Anti-phase variations of magnetic field and ion plasma pressures are analyzed by searching for morphological similarities in the two time series. It is found that longitudinal and transverse magnetic field variations with respect to the background magnetic field are of the same order of magnitude. Plasma velocities are processed for each time period of the local dissimilarity in the pressure time series. Velocity disturbances occur mainly transversely to the local field line. The data reveal the rotation of the velocity vector. Because of the field line curvature, there is no fixed position of the rotational plane in the space. These vortices are localized in the regions of anti-phase variations of the magnetic field and plasma pressures, and the vortical flows are associated with the compressional Pc5 wave process. A theoretical model is proposed to explain the main features of the nonlinear wave processes. Our main goal is to study coupling of drift Alfven wave and magnetosonic wave in a warm inhomogeneous plasma. A vortex is the partial solution of the set of the equations when the compression is neglected. A compression effect gives rise to a nonlinear soliton-like solution.Key words. Magnetosphere physics (magnetotail) · Space plasma physics (kinetic and MHD theory; non-linear phenomena)

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.

Depth of penetration of lubricant fluids and water in Queenston shale of southern Ontario

2017 ◽  
Vol 54 (2) ◽  
pp. 248-257 ◽  
Author(s):  
Hayder Mohammed Salim Al-Maamori ◽  
M. Hesham El Naggar ◽  
Silvana Micic
Keyword(s):  
Polymer Solution ◽  
Penetration Depth ◽  
Deformation Behaviour ◽  
Test Procedure ◽  
Time Dependent ◽  
Efficient Technique ◽  
Depth Of Penetration ◽  
Water Penetration ◽  
Southern Ontario ◽  
Rock Formation

Queenston shale is a rock formation located in southern Ontario in Canada that exhibits time-dependent deformation behaviour induced by water penetration. Microtunnelling is an efficient technique that can be used to construct pipelines and tunnels in Queenston shale. In this technique, lubricant fluids, such as bentonite solution and polymer solution, are utilized, which can have a significant impact on the time-dependant deformation (i.e., swelling) of Queenston shale within their depth of influence. A test procedure was developed in this research to investigate the depth of penetration of lubricant fluids and water in Queenston shale. These fluids were applied under pressure, similar to that used in the microtunnelling process, on Queeenston shale specimens. The depth of penetration of these fluids into the test specimens was monitored with time. It was concluded that the penetration depth varied for the various fluids considered. Water had the deepest penetration into Queenston shale. Based on the observed results, an equation is developed to predict the depth of penetration of various fluids in the Queenston shale mass. Results of this research can assist in evaluating the depth of influence of various fluids in Queenston shale and the associated swelling zone can be predicted.

scholarly journals A two-fluid model describing the finite-collisionality, stationary Alfvén wave in anisotropic plasma

2008 ◽  
Vol 15 (6) ◽  
pp. 957-964 ◽  
Author(s):  
S. M. Finnegan ◽  
M. E. Koepke ◽  
D. J. Knudsen
Keyword(s):  
Fluid Model ◽  
Collisionless Plasma ◽  
Alfven Wave ◽  
Temperature Anisotropy ◽  
Thermal Pressure ◽  
Exclusion Region ◽  
Two Fluid Model ◽  
The Magnetic Field ◽  
Range Of Values ◽  
Two Fluid

Abstract. The stationary inertial Alfvén (StIA) wave (Knudsen, 1996) was predicted for cold, collisionless plasma. The model was generalized (Finnegan et al., 2008) to include nonzero values of electron and ion collisional resistivity and thermal pressure. Here, the two-fluid model is further generalized to include anisotropic thermal pressure. A bounded range of values of parallel electron drift velocity is found that excludes periodic stationary Alfvén wave solutions. This exclusion region depends on the value of the local Alfvén speed VA, plasma beta perpendicular to the magnetic field β⊥ and electron temperature anisotropy.

scholarly journals Two-fluid simulations of waves in the solar chromosphere

2019 ◽  
Vol 627 ◽  
pp. A25 ◽  
Author(s):  
B. Popescu Braileanu ◽  
V. S. Lukin ◽  
E. Khomenko ◽  
Á. de Vicente
Keyword(s):  
Acoustic Waves ◽  
Hydrogen Plasma ◽  
The Other ◽  
Alfven Wave ◽  
Numerical Code ◽  
Solar Chromosphere ◽  
Charged Fluid ◽  
Induction Equation ◽  
The Waves ◽  
Two Fluid

Solar chromosphere consists of a partially ionized plasma, which makes modeling the solar chromosphere a particularly challenging numerical task. Here we numerically model chromospheric waves using a two-fluid approach with a newly developed numerical code. The code solves two-fluid equations of conservation of mass, momentum, and energy, together with the induction equation for the case of the purely hydrogen plasma with collisional coupling between the charged and neutral fluid components. The implementation of a semi-implicit algorithm allows us to overcome the numerical stability constraints due to the stiff collisional terms. We test the code against analytical solutions of acoustic and Alfvén wave propagation in uniform medium in several regimes of collisional coupling. The results of our simulations are consistent with the analytical estimates, and with other results described in the literature. In the limit of a large collisional frequency, the waves propagate with a common speed of a single fluid. In the other limit of a vanishingly small collisional frequency, the Alfvén waves propagate with an Alfvén speed of the charged fluid only, while the perturbation in neutral fluid is very small. The acoustic waves in these limits propagate with the sound speed corresponding to either the charges or the neutrals, while the perturbation in the other fluid component is negligible. Otherwise, when the collision frequency is similar to the real part of the wave frequency, the interaction between charges and neutrals through momentum-transfer collisions cause alterations of the waves frequencies and damping of the wave amplitudes.

Nonlinear decay of a propagating lower-hybrid wave in a plasma

1978 ◽  
Vol 19 (1) ◽  
pp. 87-96 ◽  
Author(s):  
P. K. Shukla ◽  
M. A. Mamedow
Keyword(s):  
Electromagnetic Waves ◽  
Fluid Model ◽  
Wave Interaction ◽  
Alfven Wave ◽  
Lower Hybrid ◽  
Threshold Condition ◽  
Hybrid Wave ◽  
Lower Hybrid Wave ◽  
Two Fluid Model ◽  
Two Fluid

This paper studies the nonlinear coupling between a large amplitude propagating lower-hybrid wave and two electromagnetic waves in a plasma. Using a two-fluid model and Vlasov and Maxwell's equations, we derive a dispersion relation governing this three-wave interaction process. It is shown that a finite wavenumber lower-hybrid pump can decay into a whistler and a kinetic Alfvén wave. Calculations of the threshold condition suggest that this decay process may occur both in the laboratory and in the ionosphere.

MODELING OF IRRIGATION CHANNELS — A COMPARATIVE STUDY

2007 ◽  
Vol 18 (04) ◽  
pp. 739-748 ◽  
Author(s):  
OLIVIER MARCOU ◽  
BASTIEN CHOPARD ◽  
SAMIRA EL YACOUBI
Keyword(s):  
Lattice Boltzmann ◽  
Stationary Regime ◽  
Irrigation Canal ◽  
Fluid System ◽  
Venant Equation ◽  
Irrigation Channels ◽  
Two Fluid ◽  
Theoretical Results ◽  
Water Profile

A free surface Lattice Boltzmann (LB) model – based on a two-fluid system – is considered to simulate the flow of water in an irrigation canal. We compare the behavior of our numerical simulations with simple experiments and theoretical results obtained from the Saint-Venant equation, the partial differential equation commonly used to describe water flow in irrigation canals. The case study we consider are (1) the height of water along the canal in a stationary regime and (2) a draining experiment. The comparisons show that the two-fluid LB approach captures correctly the draining speed and the qualitative water profile.

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