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In most data-scientific approaches, the principle of Maximum Entropy (MaxEnt) is used to a posteriori justify some parametric model which has been already chosen based on experience, prior knowledge or computational simplicity. In a…

Methodology · Statistics 2022-06-29 Orestis Loukas , Ho Ryun Chung

To understand the essential physics needed to reproduce magnetic reconnection events in 2.5-D particle-in-cell (PIC) simulations, we revisit the Geospace Environmental Modeling (GEM) setup. We set up a 2-D Harris current sheet (that also…

Earth and Planetary Astrophysics · Physics 2017-09-19 Philippe-A. Bourdin

A minimal model for magnetic reconnection and, generally, low-frequency dynamics in low-beta plasmas is proposed. The model combines analytical and computational simplicity with physical realizability: it is a rigorous limit of gyrokinetics…

Plasma Physics · Physics 2011-10-25 Alessandro Zocco , Alexander Schekochihin

Vector displacements expressed in spherical coordinates are proposed. They correspond to electromagnetic fields in vacuum that globally rotate about an axis and display many circular patterns on the surface of a sphere. The fields basically…

Classical Physics · Physics 2021-06-11 Daniele Funaro

A well-known result across information theory, machine learning, and statistical physics shows that the maximum entropy distribution under a mean constraint has an exponential form called the Gibbs-Boltzmann distribution. This is used for…

Machine Learning · Computer Science 2020-06-26 Amir R. Asadi , Emmanuel Abbe

A new kinetic model is proposed where the equilibrium distribution with bounded support has a range of velocities about two average velocities in 1D. In 2D, the equilibrium distribution function has a range of velocities about four average…

Fluid Dynamics · Physics 2023-08-15 Shashi Shekhar Roy , S. V. Raghurama Rao

The fluid-scale evolution of relativistic magnetic reconnection is investigated by using two-fluid and magnetofluid simulation models. Relativistic two-fluid simulations demonstrate the meso-scale evolution beyond the kinetic scales, and…

High Energy Astrophysical Phenomena · Physics 2011-10-17 Seiji Zenitani , Michael Hesse , Alex Klimas

Recently, an effective {\it membrane theory} was proposed that describes the ``hydrodynamic'' regime of the entanglement dynamics for general chaotic systems. Motivated by the new {\it bit threads} formulation of holographic entanglement…

High Energy Physics - Theory · Physics 2021-11-29 Cesar A. Agón , Márk Mezei

This paper is concerned with the analysis of time-harmonic electromagnetic scattering from plasmonic inclusions in the finite frequency regime beyond the quasi-static approximation. The electric permittivity and magnetic permeability in the…

Analysis of PDEs · Mathematics 2019-01-29 Hongjie Li , Shanqiang Li , Hongyu Liu , Xianchao Wang

Using fully kinetic 3D simulations, the reconnection dynamics of asymmetric current sheets are examined at the Earth's magnetopause. The plasma parameters are selected to model MMS magnetopause diffusion region crossings with guide fields…

Electrostatic turbulence in weakly collisional, magnetized plasma can be interpreted as a cascade of entropy in phase space, which is proposed as a universal mechanism for dissipation of energy in magnetized plasma turbulence. When the…

Plasma Physics · Physics 2013-05-29 T. Tatsuno , W. Dorland , A. A. Schekochihin , G. G. Plunk , M. Barnes , S. C. Cowley , G. G. Howes

The endpoint distribution and dynamics of semiflexible fibers is studied by numerical simulation. A brief overview is given over the analytical theory of flexible and semiflexible polymers. In particular, a closed expression is given for…

Soft Condensed Matter · Physics 2013-06-13 Robert D. Groot

We consider the mass heterogeneity in a gas of polydisperse hard particles as a key to optimizing a dynamical property: the kinetic relaxation rate. Using the framework of the Boltzmann equation, we study the long time approach of a…

Soft Condensed Matter · Physics 2015-06-17 Matthieu Barbier , Emmanuel Trizac

A 2.5-dimensional magnetohydrodynamics simulation analysis of the energy release for three different reconnection regimes is presented. The system under investigation consists in a current-sheet located in a medium with a strong density…

Solar and Stellar Astrophysics · Physics 2011-02-24 Lapo Bettarini , Giovanni Lapenta

We present particle-in-cell simulations of collisionless magnetic reconnection in a system (like the magnetopause) with a large density asymmetry across the current layer. In the presence of an ambient component of the magnetic field…

Space Physics · Physics 2015-06-26 M. Swisdak , B. N. Rogers , J. F. Drake , M. A. Shay

In Monte Carlo simulation, lattice field theory with a $\theta$ term suffers from the sign problem. This problem can be circumvented by Fourier-transforming the topological charge distribution $P(Q)$. Although this strategy works well for…

High Energy Physics - Lattice · Physics 2016-09-01 M. Imachi , Y. Shinno , H. Yoneyama

The electron inertia term and the off-diagonal electron pressure terms are well-known for the frozen-in condition breakdown in collisionless magnetic reconnection, which are naturally kinetic and difficult to be employed in…

Plasma Physics · Physics 2025-06-12 H. W. Zhang , Z. W. Ma , T. Chen

An implicit Euler finite-volume scheme for general cross-diffusion systems with volume-filling constraints is proposed and analyzed. The diffusion matrix may be nonsymmetric and not positive semidefinite, but the diffusion system is assumed…

Numerical Analysis · Mathematics 2021-05-13 Ansgar Jüngel , Antoine Zurek

Magnetic reconnection plays a crucial role in violent energy conversion occurring in the environments of high electrical conductivity, such as the solar atmosphere, magnetosphere, and fusion devices. We focus on the morphological features…

Astrophysics · Physics 2009-11-13 J. Lin , S. R. Cranmer , C. J. Farrugia

This work presents neural network based minimal entropy closures for the moment system of the Boltzmann equation, that preserve the inherent structure of the system of partial differential equations, such as entropy dissipation and…

Numerical Analysis · Mathematics 2022-01-26 Steffen Schotthöfer , Tianbai Xiao , Martin Frank , Cory D. Hauck
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