Landau damped kinetic Alfvén waves and coronal heating

2009 ◽  
Vol 76 (2) ◽  
pp. 239-246 ◽  
Author(s):  
R. P. SHARMA ◽  
SACHIN KUMAR
Keyword(s):  
Solar Corona ◽  
Initial Conditions ◽  
Planck Equation ◽  
Alfven Waves ◽  
Coronal Heating ◽  
Landau Damping ◽  
Alfvén Waves ◽  
Energetic Electrons ◽  
Turbulent Spectra ◽  
Kinetic Alfvén Waves

AbstractSome recent observations of solar corona suggest that the kinetic Alfvén waves (KAWs) turbulence may be responsible for electron acceleration in solar corona and coronal heating. In the present research, we investigate the turbulent spectra of KAW due to filamentation process in the presence of Landau damping and particle energization. We present here the numerical simulation of model equation governing the nonlinear dynamics of the KAW in the presence of Landau damping. When the ponderomotive and Joule heating nonlinearities are incorporated in the KAW dynamics, the power spectra of the turbulent field is evaluated and used for particle heating. Our results reveal the formation of damped coherent magnetic filamentary structures and the turbulent spectra. The effect of Landau damping is to make the turbulent spectra steeper. Two types of scalings k−3.6 and k−4 have been obtained. We have studied the turbulence with different initial conditions. Using the Fokker–Planck equation with the new velocity space diffusion coefficient, we find the distribution function of energetic electrons in these turbulent structures. Landau damped KAWs may be responsible for the acceleration of the energetic electrons in solar corona and coronal heating.

Linear kinetic Alfvén waves in inhomogeneous plasma: Effects of Landau damping

2016 ◽  
Vol 113 (2) ◽  
pp. 25001 ◽  
Author(s):  
R. P. Sharma ◽  
R. Goyal ◽  
Nidhi Gaur ◽  
Earl E. Scime
Keyword(s):  
Inhomogeneous Plasma ◽  
Alfven Waves ◽  
Landau Damping ◽  
Alfvén Waves ◽  
Plasma Effects ◽  
Linear Kinetic ◽  
Kinetic Alfvén Waves

Nonlinear evolution of kinetic Alfvén waves and the turbulent spectra

2008 ◽  
Vol 15 (8) ◽  
pp. 082902 ◽  
Author(s):  
R. P. Sharma ◽  
Sachin Kumar ◽  
H. D. Singh
Keyword(s):  
Nonlinear Evolution ◽  
Alfven Waves ◽  
Alfvén Waves ◽  
Turbulent Spectra ◽  
Kinetic Alfvén Waves

Nonlinear interaction of obliquely propagating Alfvén waves and kinetic Alfvén waves in solar wind plasmas

2013 ◽  
Vol 79 (5) ◽  
pp. 927-931 ◽  
Author(s):  
NITIN YADAV ◽  
R. P. SHARMA
Keyword(s):  
Solar Wind ◽  
Nonlinear Interaction ◽  
Modulational Instability ◽  
Alfven Waves ◽  
Inertial Range ◽  
Alfven Wave ◽  
Alfvén Waves ◽  
Dynamical Equations ◽  
Turbulent Spectra ◽  
Kinetic Alfvén Waves

AbstractThe nonlinear interaction of kinetic Alfvén waves (KAWs) with other possible plasma modes is considered to be responsible for the observed solar wind turbulent spectrum. In the present paper, a new channel of interaction between a KAW and an obliquely propagating Alfvén wave (AW) has been proposed. The governing dynamical equations are derived and the nonlinear interaction between the two wave modes KAW and AW is studied. The growth rate of modulational instability has been calculated. The nonlinear evolution of KAW filamentation and turbulent spectra has also been discussed. In the inertial range, energy cascade follows nearly Kolmogorov scaling, and after inertial range it follows −2.5 scaling in dispersive range. The obtained results indicate that the proposed mechanism may be responsible for transferring the energy from smaller wavenumbers to larger wavenumbers in the solar wind plasmas. The relevance of the present study with recent Cluster spacecraft observations has also been pointed out.

scholarly journals Nonlinear excitation of kinetic Alfvén waves and whistler waves by electron beam-driven Langmuir waves in the solar corona

2003 ◽  
Vol 409 (1) ◽  
pp. 331-345 ◽  
Author(s):  
Yu. Voitenko ◽  
M. Goossens ◽  
O. Sirenko ◽  
A. C.-L. Chian
Keyword(s):  
Electron Beam ◽  
Solar Corona ◽  
Alfven Waves ◽  
Alfvén Waves ◽  
Whistler Waves ◽  
Nonlinear Excitation ◽  
Langmuir Waves ◽  
Kinetic Alfvén Waves

Anisotropic turbulence of kinetic Alfvén waves and heating in solar corona

2019 ◽  
Vol 19 (12) ◽  
pp. 185
Author(s):  
Hemam Dinesh Singh ◽  
Bheem Singh Jatav
Keyword(s):  
Solar Corona ◽  
Alfven Waves ◽  
Alfvén Waves ◽  
Anisotropic Turbulence ◽  
Kinetic Alfvén Waves

scholarly journals Electron Landau damping of kinetic Alfvén waves in simulated magnetosheath turbulence

2020 ◽  
Vol 27 (10) ◽  
pp. 102901
Author(s):  
Sarah A. Horvath ◽  
Gregory G. Howes ◽  
Andrew J. McCubbin
Keyword(s):  
Alfven Waves ◽  
Landau Damping ◽  
Alfvén Waves ◽  
Kinetic Alfvén Waves

scholarly journals A Hamiltonian gyrofluid model based on a quasi-static closure

2020 ◽  
Vol 86 (4) ◽  
Author(s):  
E. Tassi ◽  
T. Passot ◽  
P. L. Sulem
Keyword(s):  
Phase Velocity ◽  
Hamiltonian Structure ◽  
Alfven Waves ◽  
Landau Damping ◽  
Hamiltonian Reduction ◽  
Larmor Radius ◽  
Alfvén Waves ◽  
Magnetic Fluctuations ◽  
Temperature Anisotropy ◽  
Kinetic Alfvén Waves

A Hamiltonian six-field gyrofluid model is constructed, based on closure relations derived from the so-called ‘quasi-static’ gyrokinetic linear theory where the fields are assumed to propagate with a parallel phase velocity much smaller than the parallel particle thermal velocities. The main properties captured by this model, primarily aimed at exploring fundamental problems of interest for space plasmas such as the solar wind, are its ability to provide a reasonable agreement with kinetic theory for linear low-frequency modes, and at the same time to ensure a Hamiltonian structure in the absence of explicit dissipation. The model accounts for equilibrium temperature anisotropy, ion and electron finite Larmor radius corrections, electron inertia, magnetic fluctuations along the direction of a strong guide field and parallel Landau damping, introduced through a Landau-fluid modelling of the parallel heat transfers for both gyrocentre species. Remarkably, the quasi-static closure leads to exact and simple expressions for the nonlinear terms involving gyroaveraged electromagnetic fields and potentials. One of the consequences is that a rather natural identification of the Hamiltonian structure of the model becomes possible when Landau damping is neglected. A slight variant of the model consists of a four-field Hamiltonian reduction of the original six-field model, which is also used for the subsequent linear analysis. In the latter, the dispersion relations of kinetic Alfvén waves and the firehose instability are shown to be correctly reproduced, relatively far in the sub-ion range (depending on the plasma parameters), while the spectral range where the slow-wave dispersion relation and the field-swelling instabilities are precisely described is less extended. This loss of accuracy originates from the breaking of the condition of small phase velocity, relative to the parallel thermal velocity of the electrons (for kinetic Alfvén waves and firehose instability) or of the ions (in the case of the field-swelling instabilities).

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