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The plasma edge flow, situated at the intricate boundary between plasma and neutral particles, plays a pivotal role in the design of nuclear fusion devices such as divertors and pumps. Traditional numerical simulation methods, such as the…

Computational Physics · Physics 2024-11-14 Yifan Wen , Yanbing Zhang , Lei Wu

Particle tracking in large-scale numerical simulations of turbulent flows presents one of the major bottlenecks in parallel performance and scaling efficiency. Here, we describe a particle tracking algorithm for large-scale parallel…

Fluid Dynamics · Physics 2022-05-31 Cristian C. Lalescu , Bérenger Bramas , Markus Rampp , Michael Wilczek

Despite major advancements in nonlinear programming (NLP) and convex relaxations, most system operators around the world still predominantly use some form of linear programming (LP) approximation of the AC power flow equations. This is…

Optimization and Control · Mathematics 2021-07-19 Sleiman , Mhanna , Pierluigi , Mancarella

A detailed derivation of the Lattice Boltzmann (LB) scheme for relativistic fluids recently proposed in Ref. [1], is presented. The method is numerically validated and applied to the case of two quite different relativistic fluid dynamic…

Solar and Stellar Astrophysics · Physics 2010-12-28 M. Mendoza , B. M. Boghosian , H. J. Herrmann , S. Succi

Levy walk at the finite velocity is considered. To analyze the spatial and temporal characteristics of this process, the method of moments has been used. The asymptotic distributions of the moments (at $t\to\infty$) have been obtained for…

Astrophysics of Galaxies · Physics 2015-11-12 Viacheslav V. Saenko

We extend the eigenfunction method of computing the power-law spectrum of particles accelerated at a relativistic shock fronts to apply to shocks of arbitrarily high Lorentz factor. In agreement with the findings of Monte-Carlo simulations,…

Astrophysics · Physics 2009-10-31 J. G. Kirk , A. W. Guthmann , Y. A. Gallant , A. Achterberg

Particle acceleration in relativistic shocks is studied analytically in the test-particle, small-angle scattering limit, for an arbitrary velocity-angle diffusion function D. Accurate analytic expressions for the spectral index s are…

Astrophysics · Physics 2008-11-26 Uri Keshet

The accuracy of Lagrangian point-particle models for simulation of particle-laden flows may degrade when the particle and fluid momentum equations are two-way coupled. In these cases the fluid velocity at the location of the particle, which…

Fluid Dynamics · Physics 2018-10-17 Mahdi Esmaily , Jeremy Horwitz

In this work, we consider the error estimates and the long-time conservation or near-conservation of geometric structures, including energy, mass shell and phase-space volume, for four two-step symmetric methods applied to relativistic…

Numerical Analysis · Mathematics 2025-09-05 Ting Li , Bin Wang , Ruili Zhang

We report studies on first-order Fermi acceleration in parallel modified shock waves with a large scattering center compression ratio expected from turbulence transmission models. Using a Monte Carlo technique we have modeled particle…

Astrophysics · Physics 2009-11-11 Joni J. P. Virtanen , Rami Vainio

We discuss a semi-analytical solution of the transport equation for electrons at a non-relativistic shock in the presence of synchrotron energy losses. We calculate the spectrum of accelerated (test) particles at any point upstream and…

High Energy Astrophysical Phenomena · Physics 2015-05-14 Pasquale Blasi

We present evidence that relativistic shocks propagating in unmagnetized plasmas can self-consistently accelerate particles. We use long-term two-dimensional particle-in-cell simulations to study the well-developed shock structure in…

Astrophysics · Physics 2009-11-13 Anatoly Spitkovsky

We propose an extension to recently developed Relativistic Lattice Boltzmann solvers (RLBM), which allows the simulation of flows close to the free streaming limit. Following previous works [Phys. Rev. C 98 (2018) 035201], we use product…

The phase space flow of a dynamical system leading to the solution of Linear Programming (LP) problems is explored as an example of complexity analysis in an analog computation framework. An ensemble of LP problems with $n$ variables and…

Statistical Mechanics · Physics 2009-11-07 Asa Ben-Hur , Joshua Feinberg , Shmuel Fishman , Hava T. Siegelmann

A relativistic diffusion model with cylindrical symmetry, which propagates an initial state based on quantum chromodynamics in time towards a thermal equilibrium limit, is derived from nonequilibrium-statistical considerations: Adapting an…

High Energy Physics - Phenomenology · Physics 2024-03-29 Johannes Hoelck , Georg Wolschin

We investigate the transformation of the distribution function in the relativistic case, a problem of interest in plasma when particles with high (relativistic) velocities come into play as for instance in radiation belt physics, in the…

Space Physics · Physics 2011-10-18 R. A. Treumann , R. Nakamura , W. Baumjohann

We present a novel flow-based kinetic approach, inspired by continuous normalizing flows, for plasma simulation that unifies the complementary strengths of direct Vlasov solvers and particle-based methods. By tracking the distribution…

Plasma Physics · Physics 2025-01-29 Bowen Zhu , Jian Wu , Yuanbo Lu

Strong non-relativistic shocks are known to accelerate particles up to relativistic energies. However, for Diffusive Shock Acceleration electrons must have a highly suprathermal energy, implying a need for very efficient pre-acceleration.…

Plasma Physics · Physics 2023-10-24 Karol Fulat , Artem Bohdan , Gabriel Torralba Paz , Martin Pohl

Relativistic shocks are present in all high-energy astrophysical processes involving relativistic plasma outflows interacting with their ambient medium. While a well understood process in the context of relativistic hydrodynamics and ideal…

High Energy Astrophysical Phenomena · Physics 2023-11-28 Argyrios Loules , Nektarios Vlahakis

A recently proposed technique correlating electric fields and particle velocity distributions is applied to single-point time series extracted from linearly unstable, electrostatic numerical simulations. The form of the correlation, which…

Plasma Physics · Physics 2017-04-05 Kristopher G Klein