Related papers: Stable and Radioactive Nuclei in a Diffusion Model
We have studied the impact of cosmic-ray acceleration in SNR on the spectra of cosmic-ray nuclei in the Galaxy using a series expansion of the propagation equation, which allows us to use analytical solutions for part of the problem and an…
Recent measurements of the cosmic ray (CR) antiproton flux have been shown to challenge existing CR propagation models. It was shown that the reacceleration models designed to match secondary to primary nuclei ratios (e.g., boron/carbon)…
We take a fresh look at high energy radioactive nuclei data reported in the 90's and at the positron data recently reported by PAMELA. Our aim is to study the model independent implications of these data for the propagation time scales of…
The secondary-to-primary B/C ratio is widely used to study the cosmic ray (CR) propagation processes in the Galaxy. It is usually assumed that secondary nuclei such as Li-Be-B are entirely generated by collisions of heavier CR nuclei with…
In this paper, we study the propagation of cosmic-ray nuclei and protons. We emphasize the influence of the source composition on the expected spectrum and composition on Earth as well as on the phenomenology of the transition from Galactic…
Recently AMS-02 collaboration publish their measurements of light cosmic-ray nuclei, including lithium, beryllium, boron, carbon and oxygen. All of them reveal a prominent excess above $\sim$ 200 GV, coinciding with proton and helium.…
We calculate the spectrum of blast wave models of gamma-ray burst sources, for various assumptions about the magnetic field density and the relativistic particle acceleration efficiency. For a range of physically plausible models we find…
We revisit propagation of galactic cosmic rays (CRs) in light of recent advances in CR diffusion theory in realistic interstellar turbulence. We use a tested model of turbulence in which it has been shown that fast modes dominate scattering…
In this paper we investigate the effect of stochasticity in the spatial and temporal distribution of supernova remnants on the spectrum and chemical composition of cosmic rays observed at Earth. The calculations are carried out for…
An extensive program for the calculation of galactic cosmic-ray propagation has been developed. Primary and secondary nucleons, primary and secondary electrons, and secondary positrons are included. The basic spatial propagation mechanisms…
Analysis of signal fluctuations of a locally fixed probe, caused by molecules diffusing under the probe, can be used to determine diffusion coefficients. Theoretical treatments so far have been limited to point-like particles or to…
Cosmic rays propagating in the Galaxy may excite a streaming instability when their motion is super-alfvenic, thereby producing the conditions for their own diffusion. In this paper we present the results of a self-consistent solution of…
Measurements of ultra heavy nuclei at GeV/n energies in the galactic cosmic radiation address the question of the sources (nucleosynthetic s- and r-processes). As such, the determination of CR source abundances is a promising way to…
We derive explicit, algebraic expressions for the steady-state number density of cosmic ray electrons as a function of position and energy using Green's function of the diffusion equation with energy losses for an axisymmetric distributions…
One of the fundamental issues in cosmic ray physics is to explain the nature of cosmic ray acceleration and propagation mechanisms. Thanks to the precise cosmic ray data measured by recent space experiments, we are able to investigate the…
We obtain, for the first time, an analytic theory of the forward stimulated Brillouin scattering instability of a spatially and temporally incoherent laser beam, that controls the transition between statistical equilibrium and…
We test methods for the determination of unstable modes in stellar discs: a point collocation scheme in the action sub-space, a scheme based on expansion of the density and potential on the biorthonormal basis, and a finite element method.…
Stable Diffusion is a popular Transformer-based model for image generation from text; it applies an image information creator to the input text and the visual knowledge is added in a step-by-step fashion to create an image that corresponds…
The propagated fluxes of proton, helium, and heavier primary cosmic-ray species (up to Fe) are a means to indirectly access the source spectrum of cosmic rays. We check the compatibility of the primary fluxes with the transport parameters…
The determination of the injection composition of cosmic ray nuclei within astrophysical sources requires sufficiently accurate descriptions of the source physics and the propagation - apart from controlling astrophysical uncertainties. We…