KINETIC ALFVEN WAVE DAMPING AND POWER SPECTRUM OF TURBULENCE IN THE SOLAR WIND(a)

A new model is presented that Alfvenic turbulence in the solar wind is formedby kinetic Alfven waves assembly.bThe kinetic kAlfven wave is a coupling mode ofAlfyen wave and ion acoustic wave. The kinetic Alfren wave dispersion andLandau damping are derived, and the power spectrum of interplanetary Alfrenicfluctuations is given. When kinetic AlfVen waves with different wave length arepropagating outward from the sun the nonlinear interaction in the waves assemblyevolves the turbulence fluctuations. It is derived that the power spectrum of kinetic Alfrenic turbulence P_k∝k^-3/2, with the nonlinear interaction of waves assembly far away from the Alfvenic radius (≈ 0.3AU ). In the inner of Alfvenic pointthe power spectrum P_k changes from P_k∝k^{-1 near the sun gradually to P_k∝k-3/2with the competition between wave energy cascading and Landau damping. TheLandau damping of the kinetic Alfvenic fluctuations occurs only in the inner ofAlfvenic point and disappears out of Alfvenic radius. This model can overcomethe difficulties of previous theoretical models.}