Journal ArticleDOI
Supernova shock acceleration of cosmic rays in the Galaxy.
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TLDR
In this paper, the regeneration of galactic cosmic rays by first-order Fermi acceleration due to supernova shock waves traversing interstellar space is investigated, and it is shown that if most of the volume of the interstellar medium comprises a low density ''coronal'' phase and supernova blast waves can propagate for more than 100 pc, then reacceleration of existing cosmic rays is important.Abstract:
The regeneration of galactic cosmic rays by first-order Fermi acceleration due to supernova shock waves traversing interstellar space is investigated. It is shown that if most of the volume of the interstellar medium comprises a low density ''coronal'' phase and supernova blast waves can propagate for more than 100 pc, then reacceleration of existing cosmic rays is important. Model Green's functions describing this redistribution in energy are calculated, and their properties are contrasted with stochastic and source function acceleration schemes. Shcok wave acceleration is incorporated in a model containing simple treatments of escape, ionization, radiation, and spallation loss. The injection of low energy particles treated in an ad hoc fashion. It is shown that it is possible to reproduce the observed cosmic ray spectra for protons, electrons, light, medium and heavy nucleons up to energies < or approx. =1000 GeV per nucleon with an effective galactic supernova rate that can be as low as 8 kpc/sup -2/ Myr/sup -1/. The relative importance of direct acceleration of suprathermal particles produced in a shock front and reacceleration of existing cosmic rays may be best gauged by observing the energy dependence of the abundance ratio of light to medium nucleons and the lowmore » energy proton and electron spectra. Observational tests for the importance of this acceleration mechanism are proposed.« lessread more
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Journal ArticleDOI
Particle acceleration at astrophysical shocks: A theory of cosmic ray origin
TL;DR: In this article, the theory of first order Fermi acceleration at collisionless astrophysical shock fronts is reviewed and it is argued that the wave amplitude is probably non-linear within sufficiently strong astrophysical shocks.
Journal ArticleDOI
Propagation of Cosmic-Ray Nucleons in the Galaxy
TL;DR: In this paper, a method for the numerical computation of the propagation of primary and secondary nucleons, primary electrons, and secondary positrons and electrons is described, and the height of the halo propagation region is determined using recent 10Be/9Be measurements.
Journal ArticleDOI
Nonlinear theory of diffusive acceleration of particles by shock waves
Mikhail Malkov,L. O'c. Drury +1 more
TL;DR: In this article, a review of the current theoretical understanding of this process, from the basic ideas of how a shock energizes a few reactionless particles to the advanced nonlinear approaches treating the shock and accelerated particles as a symbiotic self-organizing system, is presented.
Journal ArticleDOI
The acceleration of cosmic rays by shock waves
TL;DR: The problem of the origin of galactic cosmic rays is a particularly difficult one despite the fact that rather detailed measurements of the properties of cosmic rays can be made, at least in the vicinity of the Sun as discussed by the authors, and the current situation has been well reviewed by Lingenfelter who points out that there are several linked problems to be solved, namely the question of sources and acceleration mechanisms, propagation within the galaxy, escape from the galaxy and of course solar modulation which affects the interpretation of the observations, especially below ~ 1 GeV/nuc.
Journal ArticleDOI
Interstellar Turbulence II: Implications and Effects
John Scalo,Bruce G. Elmegreen +1 more
TL;DR: In this article, a review of the observations and theory of these effects is presented, and the theory of turbulent transport of passive tracers is reviewed, as well as the turbulent concentration of dust grains and the turbulent washout of radial abundance gradients.