Kinetic evolution and acceleration of the solar wind

We investigate the effects of kinetic wave-particle interactions on the solar wind using a global hybrid model. The model follows the evolution of the particle distributions along an inhomogeneous field line under the influence of wave-particle interactions, an ambipolar electric field that is consistent with the particle distributions themselves, and Coulomb collisions. This represents the "first results" of global evolutionary study of the solar wind that take into account these kinetic effects. The model can account for the bulk acceleration of the solar wind, the preferential heating of the helium ions over the protons, as well as the occasionally observed double-peaked proton velocity distributions.