Hydromagnetic Waves Excited by Slowly Streaming Cosmic Rays
Abstract
Cosmic rays streaming along a magnetic field generate hydromagnetic waves with a wide range in 0, the angle between the field and the direction of wave propagation. An expansion in terms of VA! (c cos 0) <<1, where VA is the Alfvén speed, is used to show that such waves are not influenced by mix ing with electrostatic wave modes and that they are generated when the mean velocity of the cosmic rays exceeds (approximately) VA/COS 0. The growth rate of the unstable waves is greater than the rate at which cosmic rays escape the galactic disk
 Publication:

The Astrophysical Journal
 Pub Date:
 June 1968
 DOI:
 10.1086/149611
 Bibcode:
 1968ApJ...152..987W