Related papers: Fractional Models of Cosmic Ray Acceleration in th…
A review is given of the main properties of the charged component of galactic cosmic rays, particles detected at Earth with an energy spanning from tens of MeV up to about 10^19 eV. After a short introduction to the topic and an historical…
After a successful development of theoretical and numerical works on Fermi acceleration at relativistic shocks, some difficulties recently raised with the scattering issue, a crucial aspect of the process. Most pioneering works were…
Based on the generic acceleration model, which suggests different types of electromagnetic interactions between the cosmic charged particles and the different configurations of the electromagnetic (plasma) fields, the ultra high energy…
Fermi bubbles are giant gamma-ray structures extended north and south of the Galactic center with characteristic sizes of order of 10 kpc recently discovered by Fermi Large Area Telescope. Good correlation between radio and gamma-ray…
I present a review of nonthermal processes in the large scale structure of the universe. After examining the properties of cosmological shock waves and their role as particle accelerators, I discuss the main observational facts, from radio…
Energetic particles in a turbulent medium can be subject to second-order Fermi acceleration due to scattering on moving plasma waves. This mechanism leads to growing particle momentum dispersion and, at the same time, increases the mean…
The study of Galactic diffuse $\gamma$ radiation combined with the knowledge of the distribution of the molecular hydrogen in the Galaxy offers a unique tool to probe the cosmic ray flux in the Galaxy. A methodology to study the level of…
We propose the particle acceleration model coupled with multiple plasmoid ejections in a solar flare. Unsteady reconnection produces plasmoids in a current sheet and ejects them out to the fast shocks, where particles in a plasmoid are…
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…
A number of seemingly {\it exotic} phenomena seen in the highest cosmic-ray experiments are briefly discussed. We argue that they indicate existence of non-statistical fluctuations and strong correlations in the fragmentation region of…
The search for gamma radiation in clusters of galaxies represents a precious tool to investigate the history of these large scale structures. Clusters or sources within them accelerate cosmic rays, as demonstrated by the detection of radio…
Cosmological hydrodynamic simulations of large scale structure in the universe have shown that accretion shocks and merger shocks form due to flow motions associated with the gravitational collapse of nonlinear structures. Estimated speed…
Energy spectra of particles accelerated by the first-order Fermi mechanism are investigated at ultrarelativistic shock waves, outside the range of Lorentz factors considered previously. For particle transport near the shock a numerical…
Context. The diffusive shock acceleration mechanism has been widely accepted as the acceleration mechanism for galactic cosmic rays. While self-consistent hybrid simulations have shown how power-law spectra are produced, detailed…
Charged particles scattering on moving inhomogenities of the magnetised interstellar medium can gain energy through the process of second-order Fermi acceleration. This energy gain depletes in turn the magnetic wave spectrum around the…
Recent multifrequency observations contribute to derive a comprehensive picture of the origin and evolution of relativistic particles in galaxy clusters. In this review I briefly discuss theoretical aspects and open problems of this…
The ratio between secondary and primary cosmic ray particles is the main source of information about cosmic ray propagation in the Galaxy. Primary cosmic rays are thought to be accelerated mainly in Supernova Remnant (SNR) shocks and then…
Nonthermal particles can be produced due to incomplete thermalization at collisionless shocks and further accelerated to very high energies via diffusive shock acceleration. In a previous study we explored the cosmic ray (CR) acceleration…
We use fractional integrals to generalize the description of hydrodynamic accretion in fractal media. The fractional continuous medium model allows the generalization of the equations of balance of mass density and momentum density. These…
Nonlinear damping of parallel propagating Alfv\'en waves in high-$\beta$ plasma is considered. Trapping of thermal ions and Coulomb collisions are taken into account. Saturated damping rate is calculated. Applications are made for cosmic…