Topic/Type: 1.1 Space & astrophysical plasmas, Poster
S. Kumar, R. P. Sharma
Centre for Energy Studies, Indian Institute of Technology Delhi 110016, India
The paper presents the numerical simulation of model equation governing the nonlinear dynamics of the kinetic Alfv?n waves (KAWs) in the low-beta plasmas. When the ponderomotive and Joule heating nonlinearities are incorporated in the KAWs dynamics, the model equation turns out to be a modified nonlinear Schr?dinger (MNLS) equation. Numerical solution of this has been obtained when the incident pump KAWs is having a small perturbation. Energy exchange between main KAWs and perturbation and the resulting filamentary structures of KAW have been studied. More detail diagnostics reveal that the dynamics of the wave is chaotic. 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. Nonlinear saturation of the instability in the form of localized structures and the resulting power spectra of the magnetic field has also been studied. Applications of the present work are to laboratory and space plasmas.