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We present a spectral Petrov-Galerkin method for the Boltzmann collision operator. We expand the density distribution $f$ to high order orthogonal polynomials multiplied by a Maxwellian. By that choice, we can approximate on the whole…

Numerical Analysis · Mathematics 2019-03-06 Gerhard Kitzler , Joachim Schöberl

A gyrokinetic model is presented that can properly describe strong flows, large and small amplitude electromagnetic fluctuations occurring on scale lengths ranging from the electron Larmor radius to the equilibrium perpendicular pressure…

Plasma Physics · Physics 2020-04-23 B. J. Frei , R. Jorge , P. Ricci

We propose a discrete lattice version of the Fokker-Planck kinetic equation along lines similar to the Lattice-Boltzmann scheme. Our work extends an earlier one-dimensional formulation to arbitrary spatial dimension $D$. A generalized…

Statistical Mechanics · Physics 2009-11-11 Daniele Moroni , Benjamin Rotenberg , Jean-Pierre Hansen , Sauro Succi , Simone Melchionna

A Fokker-Planck model for the interaction of fast ions with the thermal electrons in a quasi-neutral plasma is developed. When the fast ion population has a net flux (i.e. the distribution of the fast ions is anisotropic in velocity space)…

Plasma Physics · Physics 2020-01-08 Brian Appelbe , Mark Sherlock , Omar El-Amiri , Chris Walsh , Jeremy Chittenden

We develop a new method for proving hypocoercivity for a large class of linear kinetic equations with only one conservation law. Local mass conservation is assumed at the level of the collision kernel, while transport involves a confining…

Analysis of PDEs · Mathematics 2010-05-11 Jean Dolbeault , Clément Mouhot , Christian Schmeiser

An implicit and conservative numerical scheme is proposed for the isotropic quantum Fokker-Planck equation describing the evolution of degenerate electrons subject to elastic collisions with other electrons and ions. The electron-ion and…

Plasma Physics · Physics 2021-03-17 H. P. Le

We describe a new approach for modeling the transport of high energy particles accelerated during flares from the acceleration region in the solar corona until their eventual thermalization in the flare footpoint. Our technique numerically…

Solar and Stellar Astrophysics · Physics 2020-10-14 Joel C. Allred , Meriem Alaoui , Adam F. Kowalski , Graham S. Kerr

The Kolmogorov-Zakharov stationary states for weak wave turbulence involve solving a leading-order kinetic equation. Recent calculations of higher-order corrections to this kinetic equation using the Martin-Siggia-Rose path integral are…

Statistical Mechanics · Physics 2025-07-15 Daniel Schubring

Turbulence at kinetic scales is an unresolved and ubiquitous phenomenon that characterizes both space and laboratory plasmas. Recently, new theories, {\it in-situ} spacecraft observations and numerical simulations suggest a novel scenario…

Employing the well-known unitary equivalence between Fokker-Planck operators and Schr\"odinger Hamiltonians, we compute the quasi-normal-mode spectrum of ultrarelativistic kinetic theories with momentum-space diffusion. We show that the…

Nuclear Theory · Physics 2026-01-28 Lorenzo Gavassino

The Fokker-Planck equation describing the transport of energetic particles interacting with turbulence is difficult to solve analytically. Numerical solutions are of course possible but they are not always useful for applications. In the…

Solar and Stellar Astrophysics · Physics 2025-04-29 B. Klippenstein , A. Shalchi

A general framework for the kinetic modelling of non-relativistic polyatomic gases is proposed,where each particle is characterized both by its velocity and by its internal state, and the Boltzmann collisionoperator involves suitably…

Mathematical Physics · Physics 2023-01-05 Thomas Borsoni , Marzia Bisi , Maria Groppi

We investigate the properties of the collision operator associated to the linear Boltzmann equation for dissipative hard-spheres arising in granular gas dynamics. We establish that, as in the case of non-dissipative interactions, the gain…

Analysis of PDEs · Mathematics 2009-11-13 Luisa Arlotti , Bertrand Lods

Energetic electrons are of interest in many types of plasmas, however previous modeling of their properties has been restricted to the use of linear Fokker-Planck collision operators or non-relativistic formulations. Here, we describe a…

Plasma Physics · Physics 2016-11-28 A. Stahl , M. Landreman , O. Embréus , T. Fülöp

In the context of global gyrokinetic simulations of turbulence using a Particle-In-Cell framework, verifying the delta-f assumption with a fixed background distribution becomes challenging when determining quasi-steady state profiles…

Bubble-particle collisions in turbulence are central to a variety of processes such as froth flotation. Despite their importance, details of the collision process have not received much attention yet. This is compounded by the sometimes…

Fluid Dynamics · Physics 2025-07-16 Timothy T. K. Chan , Chong Shen Ng , Dominik Krug

We are developing a new continuum gyrokinetic code, Gkeyll, for use in edge plasma simulations, and here present initial simulations of turbulence on open field lines with model sheath boundary conditions. The code implements an energy…

Plasma Physics · Physics 2016-10-31 A. Hakim , E. L. Shi , I. G. Abel , G. W. Hammett , T. Stoltzfus-Dueck

The presence of a dispersed phase substantially modifies small-scale turbulence. However, there has not been a comprehensive mechanistically-based understanding to predict turbulence modulation. Based on the energy flux balance, we propose…

Fluid Dynamics · Physics 2023-11-23 S. Balachandar , C. Peng , L. -P. Wang

In this paper, we rigorously obtain all the equilibria of collision kernels of type "two particles give two particles" appearing in weak turbulence theory under very general assumptions, thus completing the "equality case" in Boltzmann's…

Analysis of PDEs · Mathematics 2019-09-04 Maxime Breden , Laurent Desvillettes

Fokker-Planck equations are extensively employed in various scientific fields as they characterise the behaviour of stochastic systems at the level of probability density functions. Although broadly used, they allow for analytical treatment…

Statistical Mechanics · Physics 2020-08-26 Dimitra Maoutsa , Sebastian Reich , Manfred Opper