Related papers: Cosmic Particle Acceleration: Basic Issues
Cosmic ray story begins at the beginning of XX century. More then 100 years later, most of the main issues are still open questions, as sources, acceleration mechanism, propagation and composition. There is a continuing fascination with the…
The theory of first order Fermi acceleration at shocks assumes that particles diffuse due to scattering off slow-moving magnetic irregularities. However, cosmic rays are closely tied to magnetic field lines, and the transport process,…
The origin of the highest energy cosmic rays is still unknown. The discovery of their sources will reveal the workings of the most energetic astrophysical accelerators in the universe. Current observations show a spectrum consistent with an…
Some general features of cosmic ray acceleration are summarized along with some inferences that can be drawn concerning the origin of the UHE component. The UHE luminosity density is found to be similar to that derived for GeV cosmic rays…
These lecture notes cover some of the theoretical topics associated with cosmic acceleration. Plausible explanations to cosmic acceleration include dark energy, modified gravity and a violation of the Copernican principle. Each of these…
It is well accepted today that diffusive acceleration in shocks results to the cosmic ray spectrum formation. This is in principle true for non-relativistic shocks, since there is a detailed theory covering a large range of their properties…
Galactic cosmic rays are believed to be accelerated at supernova remnants via diffusive shock acceleration. Though this mechanism gives fairly robust predictions for the spectrum of particles accelerated at the shock, the spectrum of the…
Cosmic ray acceleration in turbulent interstellar medium is considered. Turbulence is treated as ensemble of moving magnetic traps. We derive equations for particle momentum distribution function that describes acceleration of particles in…
In this chapter I give an overview of shock acceleration, including a discussion of the maximum energies possible and the shape of the spectrum near cut-off, interactions of high energy cosmic rays with, and propagation through, the…
Cosmic rays represent one of the most fascinating research themes in modern astronomy and physics. After almost a century since their discovery, a huge amount of scientific literature has been written on this topic and it is not always easy…
The origin of cosmic rays with energies higher than 10$^{20}$ eV remains a mystery. Accelerating particles up to these energies is a challenge even for the most energetic astrophysical objects known. While the isotropy in arrival directions…
Our purpose is to evaluate the rate of the maximum energy and the acceleration rate that cosmic rays acquire in the non-relativistic diffusive shock acceleration as it could apply during their lifetime in various astrophysical sites, where…
Theoretical studies of cosmic ray particle acceleration in the first-order Fermi process at relativistic shocks are reviewed. At the beginning we discuss the acceleration processes acting at mildly relativistic shock waves. An essential…
The wealth of data collected in the last few years thanks to the Pierre Auger Observatory and recently to the Telescope Array made the problem of the origin of ultra high energy cosmic rays a genuinely experimental/observational one. The…
The hypothesis that the entire cosmic ray spectrum, from $\lesssim1\,{\rm GeV}$ to $\gtrsim100\,{\rm EeV}$ energy, can be accounted for by diffusive shock acceleration on increasingly large scales is critically examined. Specifically, it is…
Motivated by recent unsuccessful efforts to detect the predicted flux of TeV gamma-rays from supernova remnants, we present a critical examination of the theory on which these predictions are based. Three crucial problems are identified:…
I give a synopsis of two aspects of the Galactic Cosmic Ray (GCR) acceleration problem: the importance of the medium energy gamma-ray window, and several specific astrophysical sources which merit further investigation.
The accelerating expansion of the universe presents an exciting, fundamental challenge to the standard models of particle physics and cosmology. I highlight some of the outstanding challenges in both developing theoretical models and…
The ISVHECRI conference series emphasizes the connection between high energy physics and cosmic ray physics--the study of elementary particles and nuclei from accelerators in the lab and from space. In this introductory paper on cosmic…
The origin of the particles in the highest energy end of the cosmic ray spectrum is discussed in the context of the wider problem of the origin of the whole cosmic radiation as observed at the Earth. In particular we focus our attention on…