scholarly journals Suspended minerogenic particle distributions in high-energy coastal environments: Optical implications

2004 ◽  
Vol 109 (C5) ◽  
Author(s):  
Robert H. Stavn
Keyword(s):  
High Energy ◽  
Coastal Environments ◽  
Particle Distributions

scholarly journals A STATISTICAL MECHANICS FRAMEWORK FOR MULTIPARTICLE PRODUCTION IN HIGH ENERGY HADRON REACTIONS

2002 ◽  
Vol 17 (40) ◽  
pp. 2627-2632 ◽  
Author(s):  
F. BUCCELLA ◽  
L. POPOVA
Keyword(s):  
Statistical Mechanics ◽  
Transverse Energy ◽  
Rest Mass ◽  
High Energy ◽  
Multiparticle Production ◽  
Particle Collisions ◽  
Particle Distributions ◽  
Energy Hadron

We deduce the particle distributions in particle collisions with multihadron-production in the framework of mechanical statistics. They are derived as functions of x, [Formula: see text] and the rest mass of different species for a fixed total number of all produced particles, inelasticity and total transverse energy. For PT larger than the mass of each particle, we have [Formula: see text] Values of <PT>π, <PT>K and [Formula: see text] in agreement with experiment are found by taking TH = 180 MeV (the Hagedorn temperature).

scholarly journals Nanodiamond Dispersions in Nanostructured Metals

2012 ◽  
Vol 18 (S5) ◽  
pp. 73-74 ◽  
Author(s):  
D. Nunes ◽  
J. B. Correia ◽  
P. A. Carvalho
Keyword(s):  
Thermal Stability ◽  
Load Transfer ◽  
Metallic Matrix ◽  
High Hardness ◽  
Processing Parameters ◽  
High Energy ◽  
Carbide Formation ◽  
Particle Distributions ◽  
Fine Grain ◽  
Grain Boundary Pinning

A microstructure refined to the nanometer scale originates mechanical property improvements [1]. However ultra-fine grain metals present low thermal stability, requiring the presence of particle dispersions to delay coarsening by grain boundary pinning. Nanoscale dispersions of diamond or graphite offer therefore thermal stability potential, combined with high hardness and thermal conductivity for diamond, and self-lubricating properties in the case of graphite. Copper-diamond (Cu-nD) and copper-graphite (Cu-G), nickel-diamond (Ni-nD) and nickel-graphite (Ni-G), as well as tungsten-diamond (W-nD) and tungsten-graphite (W-G) nanostructured composites have been produced by mechanical synthesis and subsequent heat-treatments. Fundamental challenges involve bonding carbon phases to the chosen matrices: copper exhibits an intrinsically difficult bonding with carbon; while tungsten is a strong carbide former; with Ni exhibiting intermediate characteristics. In addition, carbon phases are prone to amorphization by high-energy milling. Transmission electron microscopy (TEM) observations showed homogeneous particle distributions and intimate bonding between the metallic matrix and the carbon phases. Ring diffraction patterns of the chemically extracted carbon phases demonstrated that nanodiamond milled with Cu preserved crystallinity (Figure 1), while an essentially amorphous nature could be inferred for graphite. Systematic variation of the processing parameters enabled to minimize carbide formation with Ni and W matrices. Heat-treatment of the nanostructured of Ni-nD composites induced the transformation of nanodiamond into onion-like carbons (OLC) inside the Ni nanostructured matrix (Figure 2). Hardening mechanisms and the load transfer ability to the reinforcement particles, as well as thermal stability, have been evaluated through microhardness tests.

Multifractal analysis of charged particle distributions using horizontal visibility graph and sandbox algorithm

2017 ◽  
Vol 32 (08) ◽  
pp. 1750024 ◽  
Author(s):  
P. Mali ◽  
A. Mukhopadhyay ◽  
S. K. Manna ◽  
P. K. Haldar ◽  
G. Singh
Keyword(s):  
Model Simulation ◽  
Relativistic Quantum ◽  
Monte Carlo Model ◽  
High Energy ◽  
Quantum Molecular Dynamics ◽  
Network Systems ◽  
Emission Data ◽  
Horizontal Visibility ◽  
Particle Distributions ◽  
200 Gev

Horizontal visibility graphs (HVGs) and the sandbox (SB) algorithm usually applied for multifractal characterization of complex network systems that are converted from time series measurements, are used to characterize the fluctuations in pseudorapidity densities of singly charged particles produced in high-energy nucleus–nucleus collisions. Besides obtaining the degree distribution associated with event-wise pseudorapidity distributions, the common set of observables, typical of any multifractality measurement, are studied in [Formula: see text]O-Ag/Br and [Formula: see text]S-Ag/Br interactions, each at an incident laboratory energy of 200 GeV/nucleon. For a better understanding, we systematically compare the experiment with a Monte Carlo model simulation based on the Ultra-relativistic Quantum Molecular Dynamics (UrQMD). Our results suggest that the HVG-SB technique is an efficient tool that can characterize multifractality in multiparticle emission data, and in some cases, it is even superior to other methods more commonly used in this regard.

scholarly journals Investigation of Particle Distributions in Xe-Xe Collision at sNN=5.44 TeV with the Tsallis Statistics

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Hai-Fu Zhao ◽  
Bao-Chun Li ◽  
Hong-Wei Dong
Keyword(s):  
Transverse Momentum ◽  
Momentum Distribution ◽  
Charged Particles ◽  
High Energy ◽  
Transverse Momentum Distribution ◽  
Final State ◽  
Tsallis Statistics ◽  
Nuclear Modification Factor ◽  
Particle Distributions ◽  
Modification Factor

The distribution characteristic of final-state particles is one of the significant parts in high-energy nuclear collisions. The transverse momentum distribution of charged particles carries essential evolution information about the collision system. The Tsallis statistics is used to investigate the transverse momentum distribution of charged particles produced in Xe-Xe collisions at sNN=5.44 TeV. On this basis, we reproduce the nuclear modification factor of the charged particles. The calculated results agree approximately with the experimental data measured by the ALICE Collaboration.

scholarly journals A lepto-hadronic model for the high energy emission from the jets of FR I radiogalaxies

2010 ◽  
Vol 6 (S275) ◽  
pp. 168-169
Author(s):  
Matías M. Reynoso ◽  
María C. Medina ◽  
Gustavo E. Romero
Keyword(s):  
Steady State ◽  
High Energy ◽  
Inelastic Collisions ◽  
Proton Synchrotron ◽  
Relativistic Jets ◽  
Particle Distributions ◽  
Compact Region ◽  
Inverse Compton ◽  
High Energy Emission ◽  
Hadronic Model

AbstractWe present a lepto-hadronic model for the VHE emission from the relativistic jets of FR I radiogalaxies. We assume that protons and electrons are accelerated in a compact region near the base of the jet, and they cool emitting multiwavelength radiation as they propagate along the jet. The particle distributions are obtained using an inhomogeneous steady-state transport equation that accounts for the cooling processes as well as the convection of particles in the jet. The dominant processes that contribute to the photon SED are electron and proton synchrotron radiation, inverse Compton interactions, and the inelastic collisions pp and pγ. The accompanying neutrino output is obtained and the possibility of detection with Km3Net and IceCube is discussed for the cases of Cen A and M87.

scholarly journals THEMIS observations of compressional pulsations in the dawn-side magnetosphere: a case study

2009 ◽  
Vol 27 (10) ◽  
pp. 3725-3735 ◽  
Author(s):  
G. I. Korotova ◽  
D. G. Sibeck ◽  
V. Kondratovich ◽  
V. Angelopoulos ◽  
O. D. Constantinescu
Keyword(s):  
Magnetic Field ◽  
Radial Distance ◽  
High Energy ◽  
Convection Flow ◽  
Plasma Convection ◽  
Pressure Balance ◽  
Particle Distributions ◽  
Time Period ◽  
Low Energies ◽  
The Waves

Abstract. We present THEMIS-A low- and high-energy plasma, magnetic field, and energetic particle observations of long period (11–36 min) irregular compressional pulsations in the dawnside magnetosphere from 08:00 to 12:24 UT on 7 November 2007. We demonstrate that the pulsations maintain thermal and magnetic pressure balance, then employ finite gyroradius techniques to determine wave properties from the gyrophase distributions of 5–10 keV ions. The waves generally move sunward at velocities ~10 km s−1 with the background plasma convection flow. Wavelengths range from 6700 to 23 300 km, corresponding to azimuthal wavenumbers m from 18 to 76. Wave periods decrease with increasing radial distance. Having determined the parameters describing the waves, we consider three previously proposed explanations: generation by substorm injection, generation by bounce or drift-bounce instabilities, and generation by the drift-mirror instability. The interval was quiet geomagnetically, arguing against any relationship to substorm injections. We found that ions with low energies of 69–628 eV or high energies of 28–615 keV would have been required to account for drift-bounce resonance during this interval, but inspection reveals ion fluxes at these energies near background levels during the time period considered. On the other hand, the criteria for the drift mirror instability are marginally satisfied. As predicted for the drift mirror instability, particle distributions peak more sharply near 90° pitch angles during magnetic field strength enhancements than during strength depressions. At this point we therefore interpret the compressional pulsations observed by THEMIS A in terms of the drift mirror instability.

scholarly journals A Shock-in-Jet Synchrotron Mirror Model for Blazars

Physics ◽  
2021 ◽  
Vol 3 (4) ◽  
pp. 1112-1122
Author(s):  
Markus Böttcher
Keyword(s):  
Synchrotron Radiation ◽  
Gamma Ray ◽  
Low Frequency ◽  
High Energy ◽  
Shock Acceleration ◽  
Additional Parameter ◽  
Diffusive Shock Acceleration ◽  
Spectral Variability ◽  
Particle Distributions ◽  
Self Consistent

Reinhard Schlickeiser has made groundbreaking contributions to various aspects of blazar physics, including diffusive shock acceleration, the theory of synchrotron radiation, the production of gamma-rays through Compton scattering in various astrophysical sources, etc. This paper, describing the development of a self-consistent shock-in-jet model for blazars with a synchrotron mirror feature, is therefore an appropriate contribution to a Special Issue in honor of Reinhard Schlickeiser’s 70th birthday. The model is based on our previous development of a self-consistent shock-in-jet model with relativistic thermal and non-thermal particle distributions evaluated via Monte-Carlo simulations of diffusive shock acceleration, and time-dependent radiative transport. This model has been very successful in modeling spectral variability patterns of several blazars, but has difficulties describing orphan flares, i.e., high-energy flares without a significant counterpart in the low-frequency (synchrotron) radiation component. As a solution, this paper investigates the possibility of a synchrotron mirror component within the shock-in-jet model. It is demonstrated that orphan flares result naturally in this scenario. The model’s applicability to a recently observed orphan gamma-ray flare in the blazar 3C279 is discussed and it is found that only orphan flares with mild (≲ a factor of 2–3) enhancements of the Compton dominance can be reproduced in a synchrotron-mirror scenario, if no additional parameter changes are invoked.

scholarly journals Radiation and Polarization Signatures from Magnetic Reconnection in Relativistic Jets. II. Connection with γ-Rays

2022 ◽  
Vol 924 (2) ◽  
pp. 90
Author(s):  
Haocheng Zhang ◽  
Xiaocan Li ◽  
Dimitrios Giannios ◽  
Fan Guo ◽  
Hannes Thiersen ◽  
...  
Keyword(s):  
Magnetic Reconnection ◽  
Magnetic Energy ◽  
High Energy ◽  
Magnetized Plasma ◽  
Emission Region ◽  
Polarization Angle ◽  
Optical Polarization ◽  
Particle Distributions ◽  
Particle In Cell ◽  
Very High Energy

Abstract It is commonly believed that blazar jets are relativistic magnetized plasma outflows from supermassive black holes. One key question is how the jets dissipate magnetic energy to accelerate particles and drive powerful multiwavelength flares. Relativistic magnetic reconnection has been proposed as the primary plasma physical process in the blazar emission region. Recent numerical simulations have shown strong acceleration of nonthermal particles that may lead to multiwavelength flares. Nevertheless, previous works have not directly evaluated γ-ray signatures from first-principles simulations. In this paper, we employ combined particle-in-cell and polarized radiation transfer simulations to study multiwavelength radiation and optical polarization signatures under the leptonic scenario from relativistic magnetic reconnection. We find harder-when-brighter trends in optical and Fermi-LAT γ-ray bands as well as closely correlated optical and γ-ray flares. The swings in optical polarization angle are also accompanied by γ-ray flares with trivial time delays. Intriguingly, we find highly variable synchrotron self-Compton signatures due to inhomogeneous particle distributions during plasmoid mergers. This feature may result in fast γ-ray flares or orphan γ-ray flares under the leptonic scenario, complementary to the frequently considered minijet scenario. It may also imply neutrino emission with low secondary synchrotron flux under the hadronic scenario, if plasmoid mergers can accelerate protons to very high energy.

Sign in / Sign up

Export Citation Format

Share Document