Nonlinear coupling of kinetic Alfvén waves and magnetosonic waves in plasma

Abstract

This paper presents the model equations governing the nonlinear interaction between kinetic Alfvén waves and magnetosonic waves in plasmas (having β ≫ m_e/m_i). The nonlinear dynamical equation satisfies the modified Zakharov system of equations by taking the nonadiabatic response of the density in the form of a magnetosonic wave. We solved these model equations with numerical simulations and showed that the system becomes turbulent as it evolves. The localized magnetic filamentary structures are found in the solar wind at 1 AU. Magnetic power spectra at different times and spectral indices are calculated. The relevance of the present investigation to recent solar wind turbulence observations by Cluster is pointed out. In the present paper, two types of scaling, k^-3.4 and k^-3.6, are observed. The chaotic behavior of the localized structures and steeper spectra (of power law k^-S, 5/3 ≤ S ≤ 5.3) can be responsible for plasma heating and particle acceleration in solar wind.