Related papers: Polarization effects in cosmic-ray acceleration by…
The emission of the hard photon by the initial state is considered. The nucleon polarization and the differential cross sections for some experimental conditions have been calculated. The case of the emission of the collinear (with respect…
We present a theoretical approach to investigate the scattering of polarized electrons from light nuclei using the multipole expansion for the scattering cross section within the framework of the unified electroweak theory. Scattering…
Two extreme events in the universe, fast radio bursts (FRBs) and cosmic rays (CRs), could be correlated, where FRBs with extreme field strength near their sources may contribute to CRs. This study investigates localized particle…
The acceleration of charged particles, producing collimated mono-energetic beams, over short distances holds the promise to offer new tools in medicine and diagnostics. Here, we consider a possible mechanism for accelerating protons to high…
We investigate the shock acceleration of particles in massive galaxy mergers or collisions, and show that cosmic rays (CRs) can be accelerated up to the second knee energy ~0.1-1 EeV and possibly beyond, with a hard spectral index Gamma ~…
All the neutron star (NS) atmosphere models published so far have been calculated in the "cold plasma approximation", which neglects the relativistic effects in the radiative processes, such as cyclotron emission/absorption at harmonics of…
Transrelativistic supernovae (SNe), which are likely driven by central engines via jets or winds, have been among candidate sources of ultrahigh-energy cosmic rays (UHECRs). We investigate acceleration and survival of UHECR nuclei in the…
Cosmic ray (CR) particles arrive at the top of the Earth's atmosphere at a rate of around 1000 per square meter per second. They are mostly ionized nuclei - about 90% protons, 9% alpha particles traces of heavier nuclei and approximately 1%…
Shock waves associated with shell type supernova remnants are considered to be possible sites of cosmic ray acceleration. Since shocks are capable of accelerating electrons in addition to protons one anticipates both species to contribute…
The study of physical processes associated with particle acceleration in the open field line region above the polar cap (PC) of an isolated neutron star (NS) plays a fundamental role in our understanding and interpretation of high-energy…
Existing and planned observatories for cosmic neutrinos open up a huge window in energy from 10^7 to 10^17 GeV. Here, we discuss in particular the possibilities to use extremely energetic cosmic neutrinos as a diagnostic of astrophysical…
Accretion and merger shocks in clusters of galaxies are potential accelerators of high-energy protons, which can give rise to high-energy neutrinos through pp interactions with the intracluster gas. We discuss the possibility that protons…
It is a common belief that for magnetic fields typical for accreting neutron stars in High-Mass X-ray Binaries vacuum polarization only affects the propagation of polarized emission in the neutron star magnetosphere. We show that vacuum…
Cosmic-rays with energies exceeding 10^{19} eV are referred to as Ultra High Energy Cosmic Rays (UHECRs). The sources of these particles and their acceleration mechanism are unknown, and for many years have been the issue of much debate.…
The field of high energy particle astronomy is exciting and rapidly developing. In the last few years, we have detected extragalactic sources of intense TeV gamma radiation and individual cosmic ray particles with energies exceeding 25…
Under current conditions, the cosmic ray spectrum incident on the Earth is dominated by particles with energies < 1 GeV. Astrophysical sources including high energy solar flares, supernovae and gamma ray bursts produce high energy cosmic…
The ionization of two-active-electron systems by intense laser fields is investigated theoretically. In comparison with time-dependent Hartree-Fock and exact two electron simulation, we show that the ionization rate is overestimated in SAE…
In this paper, we study the diffusive shock acceleration of cosmic-ray protons and nuclei, taking into account all the relevant interaction processes with photon backgrounds. We investigate how the competition between protons and nuclei is…
Explicit expressions of the vertex constant for the decay of a nucleus into two charged particles for an arbitrary orbital momentum $l$ are derived for the standard expansion of the effective-range function $K_l(k^2)$, as well as when the…
We investigate the production of circularly polarised X and gamma-ray signals in cosmic accelerators such as supernova remnants and AGN jets. Proton-proton and proton-photon collisions within these sites produce a charge asymmetry in the…