Theoretical explanation of the large observed cosmic ray parallel mean free paths in the solar system

Institut für Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universität Bochum, 44780 Bochum, Germany e-mail: andreasm4@yahoo.com

Received: 14 November 2006
Accepted: 12 April 2007

Abstract

In recent observations large parallel mean free paths of charged cosmic rays which interact with the solar wind plasma have been discovered. The traditional approach to reproduce these measurements theoretically is the assumption that a large part of the magnetic fluctuations is in so-called 2D modes which are expected to be ineffective in scattering. By considering very recent results of particle scattering studies is is argued in this article that the assumption that 2D modes are ineffective in scattering is ruther questionable. By replacing the standard form of the wavespectrum of the magnetic fluctuations by a more realistic model an alternative explanation of observed cosmic ray parallel mean free paths in the solar system is provided by this article.