Cosmic ray acceleration by spiral shocks in the galactic wind

¹ Max-Planck-Institut für Kernphysik, 69029, Heidelberg, Postfach 103980, Germany e-mail: Heinrich.Voelk@mpi-hd.mpg.de
² Institute for Terrestrial Magnetism, Ionosphere and Radiowave Propagation, 142190, Troitsk, Moscow Region, Russia

Corresponding author: V. N. Zirakashvili, Zirak@izmiran.rssi.ru

Received: 17 March 2003
Accepted: 15 January 2004

Abstract

Cosmic ray acceleration by shocks related with Slipping Interaction Regions (SIRs) in the Galactic Wind is considered. SIRs are similar to Solar Wind Corotating Interaction Regions. The spiral structure of our Galaxy results in a strong nonuniformity of the Galactic Wind flow and in SIR formation at distances of 50 to 100 kpc. SIRs are not corotating with the gas and magnetic field because the angular velocity of the spiral pattern differs from that of the Galactic rotation. It is shown that the collective reacceleration of the cosmic ray particles with charge in the resulting shock ensemble can explain the observable cosmic ray spectrum beyond the “knee” up to energies of the order of  eV. For the reaccelerated particles the Galactic Wind termination shock acts as a reflecting boundary.