Jet-driven bow waves as electron accelerators in the magnetosheath: Monte Carlo simulations

2021 ◽  
Author(s):  
Laura Vuorinen ◽  
Rami Vainio ◽  
Heli Hietala ◽  
Terry Z. Liu
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Shock Acceleration ◽  
Energy Increase ◽  
Bow Waves ◽  
Bow Wave ◽  
Electron Accelerators ◽  
The Earth ◽  
Angle Scattering ◽  
Simulation Results

<p>Magnetosheath jets are fast flows of plasma frequently observed downstream of the Earth's quasi-parallel shock. Previous observations have shown that these jets can exhibit supermagnetosonic speeds relative to the background flow and develop their own bow waves or shocks. Such jets have been observed to be able to accelerate ions and electrons. In our study, we model electron acceleration by jet-driven bow waves in the magnetosheath using test-particle Monte Carlo simulations that include magnetic mirroring and pitch-angle scattering of magnetic irregularities. We compare the simulation results to spacecraft observations of similar events to understand the acceleration mechanisms at play. Our preliminary results suggest that the energy increase of electrons can be explained by shock drift acceleration at the moving bow wave. Our simulations allow us to estimate the efficiency of acceleration as a function of different jet and magnetosheath parameters. The acceleration introduced by jet-driven bow waves amplifies shock acceleration downstream of the Earth’s bow shock and may also be applicable to other shock environments.</p>

Small-angle scattering from collections of interacting hard ellipsoids of revolution studied by Monte Carlo simulations and other methods of statistical thermodynamics

1999 ◽  
Vol 32 (5) ◽  
pp. 917-923 ◽  
Author(s):  
Bo Sjöberg
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Small Angle ◽  
Chemical Potential ◽  
Compressibility Factor ◽  
Particle Method ◽  
Spherical Particles ◽  
Angle Scattering ◽  
Approximation Formulas ◽  
Experimental Values

Computer simulations using Monte Carlo methods are used to investigate the effects of interparticle correlations on small-angle X-ray and neutron scattering from moderate or highly concentrated systems of ellipsoids of revolution. Both oblate and prolate ellipsoids, of varying eccentricities and concentrations, are considered. The advantage with Monte Carlo simulation is that completely general models, both regarding particle shapes and interaction potentials, can be considered. Equations are also given that relate the nonideal part of the chemical potential, βμni, with the scattering at zero angle,I(0), and the compressibility factor,z. The quantity βμnican be obtained during the Monte Carlo simulations by using Widom's test-particle method. For spherical particles, the simulations are compared with approximation formulas based on the Percus–Yevick equation. A method is also suggested for the calculation of both βμniandzfrom experimental values ofI(0) recorded as a function of concentration.

scholarly journals MULTILEVEL BLOCKING MONTE CARLO SIMULATIONS FOR QUANTUM DOTS

2001 ◽  
Vol 15 (10n11) ◽  
pp. 1416-1425 ◽  
Author(s):  
R. EGGER ◽  
C. H. MAK
Keyword(s):  
Quantum Dots ◽  
Monte Carlo ◽  
Low Temperature ◽  
Monte Carlo Simulations ◽  
Strongly Correlated Electrons ◽  
Correlated Electrons ◽  
Strongly Correlated ◽  
Path Integral Monte Carlo ◽  
Sign Problem ◽  
Simulation Results

This article provides an introduction to the ideas behind the multilevel blocking (MLB) approach to the fermion sign problem in path-integral Monte Carlo simulations, and also gives a detailed discussion of MLB results for quantum dots. MLB can turn the exponential severity of the sign problem into an algebraic one, thereby enabling numerically exact studies of otherwise inaccessible systems. Low-temperature simulation results for up to eight strongly correlated electrons in a parabolic 20 quantum dot are presented.

Analyzing Push Schemes for Social Networking Services in Wireless Networks by Using Monte Carlo Simulations

2013 ◽  
Vol 717 ◽  
pp. 760-765
Author(s):  
Kyung Koo Jun
Keyword(s):  
Monte Carlo ◽  
Wireless Networks ◽  
Monte Carlo Simulations ◽  
Social Networking ◽  
Everyday Life ◽  
Weighting Factor ◽  
Social Networking Services ◽  
Simulation Results ◽  
Push And Pull ◽  
Do So

Social networking services such as Twitter and Facebook have occupied a large portion of our everyday life and it is expected to do so for the time being. SNS systems use both push and pull schemes to deliver contents to users. Regarding the push schemes, there are push N based scheme and timer based scheme. In this paper, we analyze the performance of both schemes by using Monte Carlo simulations and understand their characteristics. We present the simulation results that show the performance under various conditions. Moreover, we find that a weighting factor should be given more emphasis because of its significant impact on the performance. Also, we claim that the former work that analyzed PNS and TPS used wrong assumption that leads to the misconception about PNS.

Use of Monte Carlo Modeling to Aid Interpretation and Quantification of the Low Energy-Loss Electron Yield at Low Primary Energies

2008 ◽  
Vol 14 (5) ◽  
pp. 439-450 ◽  
Author(s):  
Christopher Bonet ◽  
Andrew Pratt ◽  
Mohamed M. El-Gomati ◽  
Jim A.D. Matthew ◽  
Steven P. Tear
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
High Vacuum ◽  
Stopping Power ◽  
Low Loss ◽  
Yield Curves ◽  
Beam Sample ◽  
Detector Geometry ◽  
Simulation Results ◽  
Lle Data

AbstractExperimental low-loss electron (LLE) yields were measured as a function of loss energy for a range of elemental standards using a high-vacuum scanning electron microscope operating at 5 keV primary beam energy with losses from 0 to 1 keV. The resulting LLE yield curves were compared with Monte Carlo simulations of the LLE yield in the particular beam/sample/detector geometry employed in the experiment to investigate the possibility of modeling the LLE yield for a series of elements. Monte Carlo simulations were performed using both the Joy and Luo [Joy, D.C. & Luo, S., Scanning11(4), 176–180 (1989)] expression for the electron stopping power and recent tabulated values of Tanuma et al. [Tanuma, S. et al., Surf Interf Anal37(11), 978–988 (2005)] to assess the influence of the more recent stopping power data on the simulation results. Further simulations have been conducted to explore the influence of sample/detector geometry on the LLE signal in the case of layered samples consisting of a thin C overlayer on an elemental substrate. Experimental LLE data were collected from a range of elemental samples coated with a thin C overlayer, and comparisons with Monte Carlo simulations were used to establish the overlayer thickness.

Three Dimensional Monte Carlo Simulations with Real Grain Orientations for the Role of Sub-Boundaries and Precipitates in Abnormal Grain Growth

2013 ◽  
Vol 753 ◽  
pp. 367-372
Author(s):  
Tae Wook Na ◽  
Chang Soo Park ◽  
Hyung Seok Shim ◽  
Byeong Joo Lee ◽  
Chan Hee Han ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Solid State ◽  
Monte Carlo Simulations ◽  
Grain Growth ◽  
Three Dimensional ◽  
Abnormal Grain Growth ◽  
Grain Orientations ◽  
The Matrix ◽  
Simulation Results

Three-dimensional Monte Carlo simulations with real grain orientations are performed to study the role of precipitates and sub-boundaries in the abnormal grain growth. According to the simulation results, sub-boundaries in the abnormally growing grain and precipitates in the matrix grains are necessary for the abnormal grain growth. The simulation results can be best explained by the mechanism of sub-boundary enhanced solid state wetting. The simulated microstructure is very similar to that experimentally observed.

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