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After developing a scattering theory for grazing collisions in general noncanonical phase spaces, we introduce a guiding center collision operator in five-dimensional phase space designed for plasma regimes characterized by long wavelengths…

Plasma Physics · Physics 2025-10-08 Naoki Sato , Philip J. Morrison

A gyrokinetic Coulomb collision operator is derived, which is particularly useful to describe the plasma dynamics at the periphery region of magnetic confinement fusion devices. The derived operator is able to describe collisions occurring…

Plasma Physics · Physics 2019-11-05 R. Jorge , B. J. Frei , P. Ricci

The infinite-dimensional mechanics of fluids and plasmas can be formulated as "noncanonical" Hamiltonian systems on a phase space of Eulerian variables. Singularities of the Poisson bracket operator produce singular Casimir elements that…

Mathematical Physics · Physics 2013-03-06 Z. Yoshida , P. J. Morrison

The Hamiltonian formulation of a plasma four-field fluid model that describes collisionless reconnection is presented. The formulation is noncanonical with a corresponding Lie-Poisson bracket. The bracket is used to obtain new independent…

Plasma Physics · Physics 2009-11-13 E. Tassi , P. J. Morrison , F. L. Waelbroeck , D. Grasso

We propose a methodology to infer collision operators from phase space data of plasma dynamics. Our approach combines a differentiable kinetic simulator, whose core component in this work is a differentiable Fokker-Planck solver, with a…

Plasma Physics · Physics 2026-01-19 Diogo D. Carvalho , Pablo J. Bilbao , Warren B. Mori , Luis O. Silva , E. Paulo Alves

Collisional and stochastic wave-particle dynamics in plasmas far from equilibrium are complex, temporally evolving, stochastic processes which are challenging to model. In this work, we extend previous methods coupling differentiable…

Plasma Physics · Physics 2026-04-27 Diogo D. Carvalho , Luis O. Silva , E. Paulo Alves

We discuss the dynamics and thermodynamics of systems with long-range interactions. We contrast the microcanonical description of an isolated Hamiltonian system to the canonical description of a stochastically forced Brownian system. We…

Statistical Mechanics · Physics 2009-11-10 Pierre-Henri Chavanis

A phase-space formulation of non-stationary nonlinear dynamics including both Hamiltonian (e.g., quantum-cosmological) and dissipative (e.g., dissipative laser) systems reveals an unexpected affinity between seemly different branches of…

Pattern Formation and Solitons · Physics 2019-05-30 Vladimir L. Kalashnikov , Sergey L. Cherkas

Plasmas whose Coulomb-collision rates are very small may relax on shorter time scales to non-Maxwellian quasi-equilibria, which, nevertheless, have a universal form, with dependence on initial conditions retained only via an infinite set of…

Plasma Physics · Physics 2022-10-12 Robert J. Ewart , Andrew Brown , Toby Adkins , Alexander A. Schekochihin

Under low-collisionality conditions the isotropic part of the electron velocity distribution function in a plasma becomes non-local and the electrons can be described by a single global distribution function . This is also the regime…

Plasma Physics · Physics 2019-09-24 Uwe Czarnetzki

The dynamics of an ideal fluid or plasma is constrained by topological invariants such as the circulation of (canonical) momentum or, equivalently, the flux of the vorticity or magnetic fields. In the Hamiltonian formalism, topological…

Mathematical Physics · Physics 2015-06-18 Z. Yoshida , P. J. Morrison

In cold weakly-ionized plasmas, Dreicer generation mechanism can be non-diffusive as demonstrated in [Y. Lee et. al. Phys. Rev. Lett. 133 17 175102 (2024)]. By expanding the previous letter, we present the detailed description of a proper…

Plasma Physics · Physics 2025-09-04 Yeongsun Lee , Pavel Aleynikov , Peter de Vries , Jong-Kyu Park , Yong-Su Na

In this study we develop a systematic procedure to construct a Poisson operator that describes the dynamics of a three dimensional nonholonomic system. Instead of reducing by symmetry the antisymmetric operator that links the energy…

Mathematical Physics · Physics 2020-12-22 Naoki Sato

We demonstrate that a nonthermal distribution of particles described by a kappa distribution can be accurately approximated by a weighted sum of Maxwell-Boltzmann distributions. We apply this method to modeling collision processes in…

Solar and Stellar Astrophysics · Physics 2015-09-09 Michael Hahn , Daniel Wolf Savin

In this work, the use of the Boltzmann collision operator for dissipative quantum transport is analyzed. Its mathematical role on the description of the time-evolution of the density matrix during a collision can be understood as processes…

Quantum Physics · Physics 2017-04-05 Z. Zhan , E. Colomes , X. Oriols

A nonequilibrium statistical operator method is developed for ensembles of particles obeying non-Hamiltonian equations of motion in classical phase space. The main consequences of non-zero compressibility of phase space are examined in…

Statistical Mechanics · Physics 2007-05-23 Alexander V. Zhukov , Jianshu Cao

A classical long-range-interacting $N$-particle system relaxes to thermal equilibrium on time scales growing with $N$; in the limit $N\to \infty$ such a relaxation time diverges. However, a completely non-collisional relaxation process,…

Statistical Mechanics · Physics 2022-02-09 Alessandro Santini , Guido Giachetti , Lapo Casetti

We discuss the dynamics and thermodynamics of systems with weak long-range interactions. Generically, these systems experience a violent collisionless relaxation in the Vlasov regime leading to a (usually) non-Boltzmannian quasi stationary…

Statistical Mechanics · Physics 2009-11-13 Pierre-Henri Chavanis

Quasistationary states are long-lived nonequilibrium states, observed in some systems with long-range interactions under deterministic Hamiltonian evolution. These intriguing non-Boltzmann states relax to equilibrium over times which…

Statistical Mechanics · Physics 2015-03-17 Shamik Gupta , David Mukamel

This article provides sharp constructive upper and lower bound estimates for the non-linear Boltzmann collision operator with the full range of physical non cut-off collision kernels ($\gamma > -n$ and $s\in (0,1)$) in the trilinear…

Analysis of PDEs · Mathematics 2016-02-22 Philip T. Gressman , Robert M. Strain
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