Related papers: Particle acceleration in astrophysical jets
The acceleration of ultra high energy cosmic rays is conjectured to occur through various interactions with the electromagnetic fields in different astrophysical objects, like magnetic matter clumps, besides the well-known shock and…
We consider the centrifugal acceleration of charged test particles by rotating magnetospheres which are widely believed to be responsible for the relativistic jet phenomenon in active galactic nuclei (AGN). Based on an analysis of forces…
A plasma velocity shear layer and/or a tangential flow discontinuity provide conditions allowing for energetic particle acceleration. We review such acceleration processes acting both in non-relativistic and in relativistic flows. In…
Astrophysical sources are extremely efficient accelerators. Some sources emit photons up to multi-TeV energies, a signature of the presence, within them, of particles with energies much higher than those achievable with the largest…
We consider the acceleration of particles due to a velocity shear in relativistic astrophysical flows. The basic physical picture and the formation of power law momentum spectra is discussed for a non-relativistic velocity field using a…
Recently, microquasar jets have aroused the interest of many researchers focusing on the astrophysical plasma outflows and various jet ejections. In this work, we concentrate on the investigation of electromagnetic radiation and particle…
In highly conducting astrophysical plasmas, charged particles are generically accelerated through Fermi-type processes involving repeated interactions with moving magnetized scattering centers. The present paper proposes a generalized…
Fast particles are accelerated in astrophysical environments by a variety of processes. Acceleration in reconnection sites has attracted the attention of researchers recently. In this letter we analyze the energy distribution evolution of…
Context. Converging flows with strong magnetic fields of different polarity can accelerate particles through magnetic reconnection. If the particle mean free path is longer than the reconnection layer is thick, but much shorter than the…
Shock acceleration is a ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., Buneman, Weibel and other two-stream instabilities) created in collisionless shocks are responsible for particle…
Particles are accelerated to very high, non-thermal energies in space, solar, and astrophysical plasma environments. In cosmic ray physics, the "Hillas limit" is often used as a rough estimate (or the necessary condition) of the maximum…
Observations suggest that relativistic particles play a fundamental role in the dynamics of jets emerging from active galactic nuclei as well as in their interaction with the intracluster medium. However, no general consensus exists…
Shock acceleration is an ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., the Buneman instability, two-streaming instability, and the Weibel instability) created in the shocks are…
Magnetized jets in GRBs and AGNs are thought to be efficient accelerators of particles, however, the process responsible for the acceleration is still a matter of active debate. In this work, we study the kink-instability in non-rotating…
Collapsing magnetic traps (CMTs) are one proposed mechanism for generating non-thermal particle populations in solar flares. CMTs occur if an initially stretched magnetic field structure relaxes rapidly into a lower-energy configuration,…
Aims. Relativistic jets launched from active galactic nuclei accelerate up to highly relativistic velocities within a few parsecs to tens of parsecs. The precise way in which this process takes place is still under study. While magnetic…
We derive the maximum accelerated particle energy from first-order and second-order Fermi acceleration at nonrelativistic and relativistic shocks for explosions taking place in a uniform surrounding medium. Second-order stochastic processes…
We examine limits to the efficiency for particles acceleration in shearing flows, showing that relativistic flow speeds are required for efficient gradual shear acceleration. We estimate maximum achievable particle energies for parameters…
We review the physics of the highest energy cosmic rays. The discovery of their sources, still unknown, will reveal the most energetic astrophysical objects in the universe and could unveil new physics beyond the standard model of particle…
One of the key questions in the study of relativistic jets is how magnetic reconnection occurs and whether it can effectively accelerate electrons in the jet. We performed 3D particle-in-cell (PIC) simulations of a relativistic…