scholarly journals Particle acceleration in Eta Carinae and cosmic-rays

2011 ◽  
Author(s):  
Roland Walter ◽  
Christian Farnier ◽  
Jean-Christophe LEYDER
Keyword(s):  
Particle Acceleration ◽  
Cosmic Rays ◽  
Eta Carinae

scholarly journals On particle acceleration and transport in plasmas in the Galaxy: theory and observations

2021 ◽  
Vol 87 (1) ◽  
Author(s):  
Elena Amato ◽  
Sabrina Casanova
Keyword(s):  
Particle Acceleration ◽  
Cosmic Rays ◽  
Galactic Cosmic Rays ◽  
Energetic Particles ◽  
Quality Data ◽  
Current Status ◽  
The Earth ◽  
The Galaxy ◽  
Formation And Evolution ◽  
Galaxy Assembly

Accelerated particles are ubiquitous in the Cosmos and play a fundamental role in many processes governing the evolution of the Universe at all scales, from the sub-AU scale relevant for the formation and evolution of stars and planets to the Mpc scale involved in Galaxy assembly. We reveal the presence of energetic particles in many classes of astrophysical sources thanks to their production of non-thermal radiation, and we detect them directly at the Earth as cosmic rays. In the last two decades both direct and indirect observations have provided us a wealth of new, high-quality data about cosmic rays and their interactions both in sources and during propagation, in the Galaxy and in the Solar System. Some of the new data have confirmed existing theories about particle acceleration and propagation and their interplay with the environment in which they occur. Some others have brought about interesting surprises, whose interpretation is not straightforward within the standard framework and may require a change of paradigm in terms of our ideas about the origin of cosmic rays of different species or in different energy ranges. In this article, we focus on cosmic rays of galactic origin, namely with energies below a few petaelectronvolts, where a steepening is observed in the spectrum of energetic particles detected at the Earth. We review the recent observational findings and the current status of the theory about the origin and propagation of galactic cosmic rays.

scholarly journals Interaction of Cosmic Rays with a Galactic Corona Bow-Shock

1990 ◽  
Vol 140 ◽  
pp. 183-184 ◽  
Author(s):  
M. Ostrowski
Keyword(s):  
Particle Acceleration ◽  
Cosmic Rays ◽  
Bow Shock

Basing on a simple 1-dim model, the process of diffusive particle acceleration at a galactic bow-shock is discussed.

scholarly journals Particle acceleration in winds of star clusters

2021 ◽  
Author(s):  
G Morlino ◽  
P Blasi ◽  
E Peretti ◽  
P Cristofari
Keyword(s):  
Particle Acceleration ◽  
Cosmic Rays ◽  
Supernova Remnants ◽  
Star Clusters ◽  
Cosmic Ray ◽  
Maximum Energy ◽  
Termination Shock ◽  
Shock Acceleration ◽  
Acceleration Process ◽  
Diffusive Shock Acceleration

Abstract The origin of cosmic rays in our Galaxy remains a subject of active debate. While supernova remnant shocks are often invoked as the sites of acceleration, it is now widely accepted that the difficulties of such sources in reaching PeV energies are daunting and it seems likely that only a subclass of rare remnants can satisfy the necessary conditions. Moreover the spectra of cosmic rays escaping the remnants have a complex shape that is not obviously the same as the spectra observed at the Earth. Here we investigate the process of particle acceleration at the termination shock that develops in the bubble excavated by star clusters’ winds in the interstellar medium. While the main limitation to the maximum energy in supernova remnants comes from the need for effective wave excitation upstream so as to confine particles in the near-shock region and speed up the acceleration process, at the termination shock of star clusters the confinement of particles upstream in guaranteed by the geometry of the problem. We develop a theory of diffusive shock acceleration at such shock and we find that the maximum energy may reach the PeV region for powerful clusters in the high end of the luminosity tail for these sources. A crucial role in this problem is played by the dissipation of energy in the wind to magnetic perturbations. Under reasonable conditions the spectrum of the accelerated particles has a power law shape with a slope 4÷4.3, in agreement with what is required based upon standard models of cosmic ray transport in the Galaxy.

scholarly journals Bohm Diffusion and Cosmic-Ray-Modified Shocks

1994 ◽  
Vol 142 ◽  
pp. 981-983
Author(s):  
Peter Duffy
Keyword(s):  
Particle Acceleration ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
Shock Acceleration ◽  
Back Reaction ◽  
Acceleration Of Particles ◽  
Diffusive Shock Acceleration ◽  
Spacetime Structure ◽  
Wide Range ◽  
Self Consistent

AbstractA numerical solution to the problem of self-consistent diffusive shock acceleration is presented. The cosmic rays are scattered, accelerated and exert a back-reaction on the gas through their interaction with turbulence frozen into the local fluid frame. Using a grid with a hierarchical spacetime structure the physically interesting limit of Bohm diffusion (к ∝ pv), which introduces a wide range of diffusion lengthscales and acceleration timescales, can be studied. Some implications for modified shocks and particle acceleration are presented.Subject headings: acceleration of particles — cosmic rays — diffusion — shock waves

Particle Acceleration in the Disk-Halo System

1991 ◽  
Vol 144 ◽  
pp. 377-386
Author(s):  
Reinhard Schlickeiser
Keyword(s):  
Particle Acceleration ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
Energy Spectra ◽  
Galactic Wind ◽  
Γ Rays ◽  
Γ Ray

The recent observations of the nonthermal properties of the halo of our Galaxy at radio and γ-ray wavelengths are summarized. Radio and γ-ray data show a similar spectral flattening with Galactic height towards the anticenter direction, which is interpreted as a cosmic-ray effect. Several theoretical explanations for the flattening of the energy spectra of the radiating cosmic-ray electrons (in the radio) and nucleons (in γ-rays) are reviewed including propagation of cosmic rays in an accelerating Galactic wind and the presence of cosmic-ray sources with flat energy spectra in the halo.

scholarly journals Shock Waves, Particle Acceleration and Non-Thermal Emission

1988 ◽  
Vol 101 ◽  
pp. 309-324
Author(s):  
R.D. Blandford
Keyword(s):  
Numerical Simulation ◽  
Particle Acceleration ◽  
Cosmic Rays ◽  
Shock Waves ◽  
Supernova Remnants ◽  
Thermal Emission ◽  
Interplanetary Shock ◽  
Galactic Cosmic Rays ◽  
Recent Developments ◽  
Shock Fronts

AbstractSome recent developments in the theory of particle acceleration at supernova shock fronts are reviewed and the confrontation of this theory with measurements of galactic cosmic rays and observations of supernova remnants is discussed. Supernova shock waves are able to account for the energetics, spectrum and composition of galactic cosmic rays, though it remains difficult to understand acceleration of ∼ 105 GeV particles. Recent developments in the analysis of interplanetary shock waves and in the numerical simulation of quasi-parallel shocks are encouraging. Interpretations of different categories of remnants are reviewed and a speculative interpretation of the optical companion to SN1987a is discussed.

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