Nonlinear kinetic Alfven-wave localized structures and turbulence generation in the solar corona

A numerical model describing kinetic Alfven waves (AWs) turbulence in coronal magnetic structure like coronal loops is presented. The governing equation representing kinetic AWs is derived using a two-fluid approach and solved by a pseudospectral method for efficient numerical simulation including effects of density fluctuations. We examined the transient dynamics of kinetic AWs through modified density resulting from associated ponderomotive effects, and the background density fluctuations. The evolution of coherent magnetic structures or magnetic slabs/filaments is studied. In addition, the turbulence possibly generated by kinetic AWs in coronal loops is examined with the help of power spectra for different values of density fluctuation amplitudes (mu). The spectra follow a Kolmogorov-like scaling (similar to k(-5/3)) in inertial range, followed by a steeper spectra with a scaling of k(-3.5) in the dissipation range. The steepening of spectra from inertial to dissipation range may indicate a stochastic energization of charged particles by manifold interactions with magnetic fluctuations, redistribution of energy from lower to higher modes of wavenumber and an energy cascade. Finally, magnetic slabs/filaments formation and turbulence by kinetic AWs inside loops numerically studied in this work can be considered as key mechanisms responsible for particle energization and heating of plasma in coronal loops.