Heating of the solar wind in the outer heliosphere
07 Feb 2006
1Institute for Problems in Mechanics of the Russian Academy of Sciences, Pr. Vernadskogo 101-1, 119526 Moscow, Russia
2Institute for Astrophysics and Extraterrestrial Research of the University of Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
Abstract. Small-scale Alfvènic turbulence in the outer heliosphere is mainly determined by a source which is connected with the instability of the initially highly anisotropic velocity distribution of interstellar pick-up protons. The main portion of the generated turbulent energy is subsequently absorbed by the pick-up protons themselves due to the cyclotron-resonant interaction between waves and particles. A small fraction of this energy can be transferred to solar wind protons resulting in their heating. The heating is more efficient in the high-speed solar wind.