Tests of Galactic Cosmic Ray Source Models
This report discusses the possibilities for observational tests of current models and ideas regarding the origin of the Galactic Cosmic Rays using facilities which are already available.
astro-ph↗
arXiv subjects
L O'C Drury
Publications and source records attributed to L O'C Drury.
Limits on diffusive shock acceleration in dense and incompletely ionised media
The limits imposed on diffusive shock acceleration by upstream ion-neutral Alfven wave damping, and by ionisation and Coulomb losses of low energy particles, are calculated. Analytic solutions are given for the steady upstream wave excitation problem with ion-neutral damping and the resulting escaping upstream flux calculated. The time dependent problem is discussed and numerical solutions presented. Finally the significance of these results for possible observational tests of shock acceleration in supernova remnants is discussed.
astro-ph↗
Non--LTE Excitation of H$_2$ in Magnetised Molecular Shocks
The observed H$_2$ line ratios in OMC--1 and IC443 are not satisfactorily explained by conventional shock excitation models. We consider the microscopic collisional processes implicit in ambipolar diffusion models of magnetised C-shocks and show that non-LTE level populations and emission line ratios are an inevitable consequence of such models. This has important implications for the use of molecular hydrogen lines as diagnostics of shock models in molecular clouds.
astro-ph↗
The gamma-ray visibility of supernova remnants: a test of cosmic ray origin
Gamma ray production in supernova remnants is discussed on the basis of current ideas about cosmic ray acceleration.
astro-ph↗