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A simple generalization of the MHD model accounting for the fluctuations of the configurations due to kinetic effects in plasmas in short times small scales is considered. The velocity of conductive fluid and the magnetic field are…

Plasma Physics · Physics 2007-10-26 D. Volchenkov , R. Lima

The equilibrium of a finite-beta cylindrical RFP plasma in the presence of saturated-amplitude tearing modes is investigated. The singularities arising from the perturbative analysis of the MHD force balance equation JxB=grad(p) are…

Plasma Physics · Physics 2007-05-23 P. Zanca , F. Sattin , E. Martines

Fluctuations of electric and magnetic fields in the collisionless plasma are found as a solution of the initial value linearized problem. The plasma initial state is on average stationary and homogeneous. When the state is stable, the…

Plasma Physics · Physics 2008-01-07 Stanislaw Mrowczynski

A general formulation of the problem of calculating the spectrum of stable and unstable eigenmodes of linearized perturbations about a magnetically confined toroidal plasma is presented. The analysis is based on a new hydromagnetic…

Plasma Physics · Physics 2017-03-07 Robert L Dewar , Li Huey Tuen , Matthew J Hole

Based on the Magnetospheric Multiscale (MMS) mission we look at magnetic field fluctuations in the Earth's magnetosheath. We apply the statistical analysis using a Fokker-Planck equation to investigate processes responsible for stochastic…

Plasma Physics · Physics 2023-09-14 Wiesław M. Macek , Dariusz Wójcik

Magnetic field fluctuations in MHD turbulence can be viewed as current sheets that are progressively more anisotropic at smaller scales. As suggested by Loureiro & Boldyrev (2017) and Mallet et al (2017), below a certain critical thickness…

Plasma Physics · Physics 2017-08-09 Stanislav Boldyrev , Nuno F. Loureiro

We examine the question of whether the formal expressions of equilibrium statistical mechanics can be applied to time independent non-dissipative systems that are not in true thermodynamic equilibrium and are nonergodic. By assuming the…

Statistical Mechanics · Physics 2007-11-09 Stephen R. Williams , Denis J. Evans

This article introduces a new 3D magnetohydrodynamic (MHD) equilibrium solver, based on the concept of admissible variations of B, p that allows for magnetic relaxation of a magnetic field in a perturbed/non-minimum energy state to a lower…

Computational Physics · Physics 2025-11-03 Tobias Blickhan , Julianne Stratton , Alan A. Kaptanoglu

Results from a numerical study of fluctuation dynamo in a collisionless, weakly magnetized plasma are presented. The key difference between this dynamo and its magnetohydrodynamic (MHD) counterpart is the adiabatic production of…

High Energy Astrophysical Phenomena · Physics 2018-08-17 Denis A. St-Onge , Matthew W. Kunz

Using direct numerical simulations of three-dimensional magnetohydrodynamic (MHD) turbulence the spatio-temporal behavior of magnetic field fluctuations is analyzed. Cases with relatively small, medium and large values of a mean background…

Plasma Physics · Physics 2016-12-21 R. Lugones , P. Dmitruk , P. D. Mininni , M. Wan , W. H. Matthaeus

Magnetohydrodynamic (MHD) solvers used to study dynamic plasmas for magnetic confinement fusion typically rely on initial conditions that describe force balance, which are provided by an equilibrium solver based on the Grad-Shafranov (GS)…

Numerical Analysis · Mathematics 2025-11-12 Rushan Zhang , Golo Wimmer , Qi Tang

A unified energy principle approach is presented for analysing the magnetohydrodynamic (MHD) stability of plasmas consisting of multiple ideal and relaxed regions. By choosing an appropriate gauge, we show that the plasma displacement…

Plasma Physics · Physics 2015-05-13 R. L. Mills , M. J. Hole , R. L. Dewar

Supersonic magnetohydrodynamic (MHD) turbulence is a ubiquitous state for many astrophysical plasmas. However, even the basic statistics for this type of turbulence remains uncertain. We present results from supersonic MHD turbulence…

Astrophysics of Galaxies · Physics 2024-05-31 James R. Beattie , Christoph Federrath , Ralf S. Klessen , Salvatore Cielo , Amitava Bhattacharjee

In this paper we show how a Lagrangian variational principle can be used to derive the SPMHD (smoothed particle magnetohydrodynamics) equations for ideal MHD. We also consider the effect of a variable smoothing length in the SPH kernels…

Astrophysics · Physics 2009-11-10 D. J. Price , J. J. Monaghan

We propose a new reduced fluid model for the study of the drift wave -- zonal flow dynamics in magnetically confined plasmas. Our model can be viewed as an extension of the classic Hasegawa-Wakatani (HW) model, and is based on an improved…

Plasma Physics · Physics 2018-11-14 Andrew J. Majda , Di Qi , Antoine J. Cerfon

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…

Although the influence of magnetic fields is regarded as vital in the star formation process, only a few magnetohydrodynamics (MHD) simulations have been performed on this subject within the smoothed particle hydrodynamics (SPH) method.…

Solar and Stellar Astrophysics · Physics 2015-05-19 Florian Bürzle , Paul C. Clark , Federico Stasyszyn , Thomas Greif , Klaus Dolag , Ralf S. Klessen , Peter Nielaba

Aims. Linear magnetohydrostatic (MHS) models of solar magnetic fields balance plasma pressure gradients, gravity and Lorentz forces where the current density is composed of a linear force-free component and a cross-field component that…

Solar and Stellar Astrophysics · Physics 2013-07-26 David MacTaggart , Abdulaziz Elsheikh , James McLaughlin , Radostin Simitev

Stochastic field theories are often constructed phenomenologically, without a systematic assessment of thermodynamic consistency or local detailed balance. This may hinder a physical description of irreversibility at the field-theoretic…

Statistical Mechanics · Physics 2026-04-29 Héctor Vaquero del Pino , François Gay-Balmaz , Hiroaki Yoshimura , Lock Yue Chew

Among the fundamental and most challenging problems of laboratory, space, and astrophysical plasma physics is to understand the relaxation processes of nearly collisionless plasmas toward quasi-stationary states; and the resultant states of…

Space Physics · Physics 2022-01-12 C. M. Espinoza , P. S. Moya , M. Stepanova , J. A. Valdivia , R. E. Navarro