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
2009 ◽  
Vol 76 (2) ◽  
pp. 239-246 ◽  
Author(s):  
R. P. SHARMA ◽  
SACHIN KUMAR

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.


2013 ◽  
Vol 79 (5) ◽  
pp. 927-931 ◽  
Author(s):  
NITIN YADAV ◽  
R. P. SHARMA

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.


2014 ◽  
Vol 21 (2) ◽  
pp. 405-416 ◽  
Author(s):  
V. Jatenco-Pereira ◽  
A. C.-L. Chian ◽  
N. Rubab

Abstract. In this paper, we present some results of previous works on Alfvén waves in a dusty plasma in different astrophysical and space regions by taking into account the effect of superthermal particles on the dispersive characteristics. We show that the presence of dust and superthermal particles sensibly modify the dispersion of Alfvén waves. The competition between different damping processes of kinetic Alfvén waves and Alfvén cyclotron waves is analyzed. The nonlinear evolution of Alfvén waves to chaos is reviewed. Finally, we discuss some applications of Alfvén waves in the auroral region of space plasmas, as well as stellar winds and star-forming regions of astrophysical plasmas.


1994 ◽  
Vol 21 (17) ◽  
pp. 1831-1834 ◽  
Author(s):  
J.-E. Wahlund ◽  
P. Louarn ◽  
T. Chust ◽  
H. de Feraudy ◽  
A. Roux ◽  
...  

2018 ◽  
Vol 123 (8) ◽  
pp. 6655-6669 ◽  
Author(s):  
Hongtao Huang ◽  
Yiqun Yu ◽  
Lei Dai ◽  
Tieyan Wang

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