Quasilinear Evolution from KAW Turbulence and Perpendicular Ion Heating in the Solar Wind

The electron and ion distribution functions resulting from quasi-linear diffusion in the turbulent solar wind plasma is calculated using the measured spectrum of the kinetic Alfven wave (KAW) fluctuations. Quasi-linear diffusion establishes a step-like profile on the distribution function over parallel velocity [1]. The size of ``plateau'' $v_m $, which can be created within the time of travel of solar wind plasma to the Earth $\sim $ 10$^{5}$ s, is estimated for electrons as $v_{me} /v_{te} \sim (10^{-7}t)^{1/6}\sim 0.5$, while for ions $v_{mi} /v_{ti} \sim (10^{-2}t)^{1/7}\sim 3$. In this case the evolution of the ion tail distribution function can be approximated as$f_{tail} \sim t^{-1/7}\exp (-\vert v_z \vert ^7/v_{mi}^7 )$. As a result, the Landau damping of KAW and whistlers in the high beta solar wind plasma is strongly diminished for $\omega