相关论文: Internal shocks in relativistic outflows: collisio…
The analysis of the frequency dependence of the observed shift of the cores of relativistic jets in active galactic nuclei (AGN) allows us to evaluate the number density of the outflowing plasma n and, hence, the multiplicity parameter,…
In many models of Gamma-Ray Bursts (GRBs) relativistic shells are responsible for the overall envelope of emission. We use kinematics and symmetry to calculate the time history and spectral evolution expected from a relativistic shell…
In explaining the physical origin of the jet composition of gamma-ray bursts (GRBs), a more general picture, i.e. the hybrid jet model (which introduced another magnetization parameter $\sigma_{0}$ on the basis of the traditional fireball…
Closed shell molecular structures are under normal conditions time-reversal invariant. Experimental evidences point, however, towards that this invariance may be locally violated when the structure is in contact with a particle reservoir.…
In this paper, the first in a series, we present a new theoretical model for the global structure and dissipation of relativistically magnetized collisionless shock waves. Quite remarkably, we find that in contrast to unmagnetized shocks,…
The radiation from afterglows of gamma-ray bursts (GRB) is generated in collisionless plasma shocks. The two main ingredients behind the radiation are high-energy, non-thermal electrons and a strong magnetic field. I argue that in order to…
The central engine causing the production of jets in radio sources may work intermittently, accelerating shells of plasma with different mass, energy and velocity. Faster but later shells can then catch up slower earlier ones. In the…
The jet composition and energy dissipation mechanism of Gamma-ray bursts (GRBs) and Blazars are fundamental questions which remain not fully understood. One plausible model is to interpret the $\gamma$-ray emission of GRBs and optical…
We review recent progress on collisionless relativistic shocks. Kinetic instability theory is briefed including its predictions and limitations. The main focus is on numerical experiments in (i) pair and (ii) electron-nucleon plasmas. The…
We present a relativistic-MHD numerical study of axisymmetric, magnetically driven jets with parameters applicable to gamma-ray burst (GRB) flows. We also present analytic expressions for the asymptotic jet shape and other flow parameters…
The hard X-ray and gamma-ray phenomenology of gamma-ray bursts (GRBs) can be explained by an external shock model where a single relativistic blast wave interacts with the surrounding medium. Besides reproducing the generic spectral…
Blazars, a class of active galaxies whose jets are relativistic and collimated flows of plasma directed along the line of sight and are prone to a slew of magneto-hydrodynamic (MHD) instabilities. We aim to study the interplay of radiation…
The Biermann Battery effect is frequently invoked in cosmic magnetogenesis and studied in High-Energy Density laboratory physics experiments. Generation of magnetic fields by the Biermann effect due to mis-aligned density and temperature…
The axisymmetric 3-D MHD outflow of a cold plasma from a magnetized and rotating astrophysical object is numerically simulated with the purpose of investigating the outflow's magnetocentrifugal acceleration and eventual collimation. Gravity…
We present the first general relativistic hydrodynamic models of the launch and evolution of relativistic jets and winds, driven by thermal energy deposition, possibly due to neutrino-antineutrino annihilation, in the close vicinity of…
Since the suggestion of relativistic shocks as the origin of gamma-ray bursts (GRBs) in early 90's, the mathematical formulation of this process has stayed at phenomenological level. One of the reasons for the slow development of…
We utilize magnetohydrodynamic (MHD) simulations to develop a numerical model for GMC-GMC collisions between nearly magnetically critical clouds. The goal is to determine if, and under what circumstances, cloud collisions can cause…
Using fully kinetic simulations, we study the scaling of the inflow speed of collisionless magnetic reconnection from the non-relativistic to ultra-relativistic limit. In the anti-parallel configuration, the inflow speed increases with the…
An elementary kinematic model for emission produced by relativistic spherical colliding shells is studied. The case of a uniform blast-wave shell with jet opening angle $\theta_j \gg 1/\Gamma$ is considered, where $\Gamma$ is the Lorentz…
We calculate the expected envelope of emission for relativistic shells under the assumption of local spherical symmetry. Gamma-Ray Burst envelopes rarely conform to the expected shape, which is similar to a FRED; a fast rise and exponential…