Particle acceleration and magnetic field amplification in supernova shells: A nonlinear Monte Carlo model

2017 ◽  
Vol 81 (4) ◽  
pp. 431-433
Author(s):  
A. M. Bykov ◽  
S. M. Osipov ◽  
D. Ellison
Keyword(s):  
Magnetic Field ◽  
Monte Carlo ◽  
Particle Acceleration ◽  
Monte Carlo Model ◽  
Field Amplification

scholarly journals Self-consistent Monte Carlo model of particle acceleration by relativistic shocks

2021 ◽  
Vol 2103 (1) ◽  
pp. 012014
Author(s):  
S M Osipov ◽  
A M Bykov ◽  
M Lemoine
Keyword(s):  
Magnetic Field ◽  
Monte Carlo ◽  
Particle Acceleration ◽  
Monte Carlo Model ◽  
Cosmic Ray ◽  
Field Amplification ◽  
Relativistic Shocks ◽  
Self Consistent ◽  
The Magnetic Field ◽  
Accelerated Particles

Abstract We present a self-consistent Monte Carlo model of particle acceleration by relativistic shock waves. The model includes the magnetic field amplification in the shock upstream by cosmic ray driven plasma instabilities. The parameters of the Monte Carlo model are obtained based on PIC calculations. We present the spectra of accelerated particles simulated in the frame of the model.

Circulation of energetic ions within Ganymede’s magnetosphere: a Monte-Carlo simulation approach

2021 ◽  
Author(s):  
Christina Plainaki ◽  
Stefano Massetti ◽  
Xianzhe Jia ◽  
Alessandro Mura ◽  
Anna Milillo ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Monte Carlo ◽  
Plasma Sheet ◽  
Monte Carlo Model ◽  
Weather Conditions ◽  
The Moon ◽  
Water Release ◽  
Energetic Ions ◽  
Surface Precipitation ◽  
Long Term Impact

<p>The study of Ganymede, the only known moon in the Solar System to possess an intrinsic magnetic field embedded within a planetary magnetosphere, is of significant importance in view of future missions to the Jovian system. Indeed, the dynamics of the entry and circulation inside Ganymede’s magnetosphere of the Jovian energetic ions, as well as the morphology of their precipitation on the moon’s surface determine the variability of the sputtered-water release and exosphere generation. The so-called planetary space weather conditions around Ganymede can also have a long-term impact on the weathering history of its icy surface.</p> <p>In this talk, I will discuss some key characteristics of the circulation of the Jovian magnetospheric ions within the environment of Ganymede as derived from the application of a single-particle Monte Carlo model driven by the electromagnetic fields from a global MHD model. In particular, the Jovian energetic ion circulation and precipitation to Ganymede’ s surface was estimated for different relative configurations between the moon’s magnetic field and Jupiter’s plasma sheet, characterized by conditions similar to those encountered during the NASA Galileo G2, G8, and G28 flybys of Ganymede (i.e., when the moon was above, inside, and below the center of Jupiter’ s plasma sheet). The resulting differences between the various surface precipitation patterns and the implications in the water sputtering rate will be discussed. The results of this preliminary analysis are relevant to ESA’ s JUICE mission and in particular to the planning of future observation strategies for studying Ganymede’ s environment.</p>

scholarly journals Three-dimensional simulations of non-resonant streaming instability and particle acceleration near non-relativistic astrophysical shocks

2019 ◽  
Vol 490 (1) ◽  
pp. 1156-1165 ◽  
Author(s):  
Allard Jan van Marle ◽  
Fabien Casse ◽  
Alexandre Marcowith
Keyword(s):  
Magnetic Field ◽  
Particle Acceleration ◽  
Three Dimensional ◽  
3D Models ◽  
Three Dimensions ◽  
Spectral Energy ◽  
Growth Speed ◽  
Field Amplification ◽  
Streaming Instability ◽  
2D And 3D

ABSTRACT We use particle-in-magnetohydrodynamics-cells to model particle acceleration and magnetic field amplification in a high-Mach, parallel shock in three dimensions and compare the result to 2D models. This allows us to determine whether 2D simulations can be relied upon to yield accurate results in terms of particle acceleration, magnetic field amplification, and the growth rate of instabilities. Our simulations show that the behaviour of the gas and the evolution of the instabilities are qualitatively similar for both the 2D and 3D models, with only minor quantitative differences that relate primarily to the growth speed of the instabilities. The main difference between 2D and 3D models can be found in the spectral energy distributions (SEDs) of the non-thermal particles. The 2D simulations prove to be more efficient, accelerating a larger fraction of the particles and achieving higher velocities. We conclude that, while 2D models are sufficient to investigate the instabilities in the gas, their results have to be treated with some caution when predicting the expected SED of a given shock.

scholarly journals Gold Nanoparticle DNA Damage by Photon Beam in a Magnetic Field: A Monte Carlo Study

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1751
Author(s):  
Mehwish Jabeen ◽  
James C. L. Chow
Keyword(s):  
Magnetic Field ◽  
Dna Damage ◽  
Monte Carlo ◽  
Gold Nanoparticle ◽  
Monte Carlo Model ◽  
Photon Beam ◽  
Dose Enhancement ◽  
The Impact ◽  
The Magnetic Field ◽  
Field Strengths

Ever since the emergence of magnetic resonance (MR)-guided radiotherapy, it is important to investigate the impact of the magnetic field on the dose enhancement in deoxyribonucleic acid (DNA), when gold nanoparticles are used as radiosensitizers during radiotherapy. Gold nanoparticle-enhanced radiotherapy is known to enhance the dose deposition in the DNA, resulting in a double-strand break. In this study, the effects of the magnetic field on the dose enhancement factor (DER) for varying gold nanoparticle sizes, photon beam energies and magnetic field strengths and orientations were investigated using Geant4-DNA Monte Carlo simulations. Using a Monte Carlo model including a single gold nanoparticle with a photon beam source and DNA molecule on the left and right, it is demonstrated that as the gold nanoparticle size increased, the DER increased. However, as the photon beam energy decreased, an increase in the DER was detected. When a magnetic field was added to the simulation model, the DER was found to increase by 2.5–5% as different field strengths (0–2 T) and orientations (x-, y- and z-axis) were used for a 100 nm gold nanoparticle using a 50 keV photon beam. The DNA damage reflected by the DER increased slightly with the presence of the magnetic field. However, variations in the magnetic field strength and orientation did not change the DER significantly.

CONNECTION BETWEEN MAGNETIC FIELD AMPLIFICATION AND BLAZAR FLARES

2014 ◽  
Vol 28 ◽  
pp. 1460180 ◽  
Author(s):  
XUHUI CHEN ◽  
RITABAN CHATTERJEE ◽  
GIOVANNI FOSSATI ◽  
MARTIN POHL
Keyword(s):  
Magnetic Field ◽  
Particle Acceleration ◽  
Gamma Ray ◽  
Field Amplification ◽  
Spectrum Radio ◽  
Astrophysical Shocks ◽  
Highly Correlated ◽  
Distinct Features ◽  
The Magnetic Field ◽  
Optical Flare

Recent multiwavelength observations of PKS 0208-512 by SMARTS, Fermi, and Swift revealed that γ-ray and optical light curves of this flat spectrum radio quasars are highly correlated, but with an exception of one large optical flare having no corresponding gamma-ray activity or even detection. On the other hand, recent advances in SNRs observations and plasma simulations both reveal that magnetic field downstream of astrophysical shocks can be largely amplified beyond simple shock compression. These amplifications, along with their associated particle acceleration, might contribute to blazar flares, including the peculiar flare of PKS 0208-512. Using our time dependent multizone blazar emission code,which tracks all the light travel time effects, we evaluate several scenarios that may represent such phenomena. Both the changes of the magnetic field and acceleration efficiency are explored as the cause of blazar flares. Under these assumption, synchrotron self-Compton and external Compton scenarios produce distinct features that favor the external Compton scenario. The optical flares with/without gamma-ray counterparts can be explained by different allocations of energy between the magnetization and particle acceleration, which in turn can be affected by the relative orientation between the magnetic field and the shock flow.

scholarly journals Particle Acceleration in Mildly Relativistic Outflows of Fast Energetic Transient Sources

Universe ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 32
Author(s):  
Andrei Bykov ◽  
Vadim Romansky ◽  
Sergei Osipov
Keyword(s):  
Monte Carlo ◽  
Particle Acceleration ◽  
Gamma Ray ◽  
Broad Band ◽  
Monte Carlo Model ◽  
High Energy ◽  
Relativistic Electrons ◽  
Particle In Cell ◽  
Transient Sources ◽  
Relativistic Outflows

Recent discovery of fast blue optical transients (FBOTs)—a new class of energetic transient sources—can shed light on the long-standing problem of supernova—long gamma-ray burst connections. A distinctive feature of such objects is the presence of modestly relativistic outflows which place them in between the non-relativistic and relativistic supernovae-related events. Here we present the results of kinetic particle-in-cell and Monte Carlo simulations of particle acceleration and magnetic field amplification by shocks with the velocities in the interval between 0.1 and 0.7 c. These simulations are needed for the interpretation of the observed broad band radiation of FBOTs. Their fast, mildly to moderately relativistic outflows may efficiently accelerate relativistic particles. With particle-in-cell simulations we demonstrate that synchrotron radiation of accelerated relativistic electrons in the shock downstream may fit the observed radio fluxes. At longer timescales, well beyond those reachable within a particle-in-cell approach, our nonlinear Monte Carlo model predicts that protons and nuclei can be accelerated to petaelectronvolt (PeV) energies. Therefore, such fast and energetic transient sources can contribute to galactic populations of high energy cosmic rays.

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