Quasilinear evolution of plasma distribution functions and consequences on wave spectrum and perpendicular ion heating in the turbulent solar wind

The measured spectrum of kinetic Alfven wave fluctuations in the turbulent solar wind plasma is used to calculate the quasi-linear evolution of the initially stable electron and ion distribution functions. The resulting ion distribution function is found to be unstable to electromagnetic left hand polarized ion cyclotron-Alfven waves as well as right hand polarized magnetosonic-whistler waves. These waves can pitch angle scatter the ion super-thermal velocity component to provide perpendicular ion heating. Additionally, right hand polarized waves transfer some part of kinetic Alfven wave flux to whistler waves.