Cosmic-Ray Life and the Stochastic Nature of the Galactic Magnetic Field

Abstract

We point out that the observed mean life for cosmic rays of ~ yrs is difficult to account for in conventional models of the galactic magnetic field. A stochastic model of the interstellar magnetic field is proposed, and is shown to provide a natural explanation of the cosmic-ray lifetimes. The random walk of magnetic lines of force, deduced from the observed turbulent motions of the gas and also from observa- tions of the polarization of starlight, leads to rapid motion of the cosmic-ray particles normal to the plane of the galactic disk