scholarly journals Effects of finite Larmor radius on equilibria with flow in reduced two-fluid models

2008 ◽  
Author(s):  
Atsushi Ito ◽  
Noriyoshi Nakajima ◽  
Olivier Sauter ◽  
Xavier Garbet ◽  
Elio Sindoni
Keyword(s):  
Larmor Radius ◽  
Fluid Models ◽  
Finite Larmor Radius ◽  
Two Fluid

Effects of collisions and gyroviscosity on gravitational instability in a two-component plasma

1972 ◽  
Vol 8 (3) ◽  
pp. 393-400 ◽  
Author(s):  
F. Herrnegger
Keyword(s):  
Gravitational Instability ◽  
Larmor Radius ◽  
Finite Larmor Radius ◽  
Two Component ◽  
Component Plasma ◽  
Jeans Criterion ◽  
Fluid Theory ◽  
The Magnetic Field ◽  
Two Fluid ◽  
Critical Wavenumber

The dispersion relation for gravitational instability has been given within the framework of a two-fluid theory. It has been shown that the Jeans criterion is changed by finite Larmor radius and by collisions for waves propagating perpendicular to the magnetic field. The critical wavenumber for instability decreases with increasing Alfvén velocity and with increasing gyroviscosity. Instability does not set in with overstabiity.

scholarly journals Finite Larmor radius regime: Collisional setting and fluid models

2019 ◽  
Vol 22 (06) ◽  
pp. 1950047
Author(s):  
Mihaï Bostan ◽  
Aurélie Finot
Keyword(s):  
Kinetic Energy ◽  
Subject Matter ◽  
Entropy Inequality ◽  
Collision Kernel ◽  
Larmor Radius ◽  
Fluid Models ◽  
Finite Larmor Radius ◽  
Collision Invariants ◽  
The Subject ◽  
Macroscopic Equations

The subject matter of this paper concerns the derivation of fluid limits for gyro-kinetic models. The arguments apply for any collision kernel satisfying the usual conservations (mass, momentum, kinetic energy) and possessing a production entropy sign. We describe the set of equilibria in terms of several moments, we determine the average collision invariants, and we write the associated macroscopic equations and the entropy inequality.

scholarly journals Electron-scale reduced fluid models with gyroviscous effects

2017 ◽  
Vol 83 (4) ◽  
Author(s):  
T. Passot ◽  
P. L. Sulem ◽  
E. Tassi
Keyword(s):  
Magnetic Energy ◽  
Pressure Fluctuations ◽  
Transverse Magnetic ◽  
Larmor Radius ◽  
Anisotropic Pressure ◽  
Turbulence Energy ◽  
Fluid Models ◽  
Magnetic Fluctuations ◽  
Pressure Balance ◽  
Finite Larmor Radius

Reduced fluid models for collisionless plasmas including electron inertia and finite Larmor radius corrections are derived for scales ranging from the ion to the electron gyroradii. Based either on pressure balance or on the incompressibility of the electron fluid, they respectively capture kinetic Alfvén waves (KAWs) or whistler waves (WWs), and can provide suitable tools for reconnection and turbulence studies. Both isothermal regimes and Landau fluid closures permitting anisotropic pressure fluctuations are considered. For small values of the electron beta parameter $\unicode[STIX]{x1D6FD}_{e}$, a perturbative computation of the gyroviscous force valid at scales comparable to the electron inertial length is performed at order $O(\unicode[STIX]{x1D6FD}_{e})$, which requires second-order contributions in a scale expansion. Comparisons with kinetic theory are performed in the linear regime. The spectrum of transverse magnetic fluctuations for strong and weak turbulence energy cascades is also phenomenologically predicted for both types of waves. In the case of moderate ion to electron temperature ratio, a new regime of KAW turbulence at scales smaller than the electron inertial length is obtained, where the magnetic energy spectrum decays like $k_{\bot }^{-13/3}$, thus faster than the $k_{\bot }^{-11/3}$ spectrum of WW turbulence.

scholarly journals Nonlinear finite-Larmor-radius effects in reduced fluid models

2008 ◽  
Vol 15 (8) ◽  
pp. 082302 ◽  
Author(s):  
A. J. Brizard ◽  
R. E. Denton ◽  
B. Rogers ◽  
W. Lotko
Keyword(s):  
Larmor Radius ◽  
Fluid Models ◽  
Finite Larmor Radius

Finite-Larmor-radius-induced global geodesic acoustic modes—a two-fluid model

2021 ◽  
Vol 61 (10) ◽  
pp. 106024
Author(s):  
Yu Wang ◽  
Tianchun Zhou ◽  
Xiaogang Wang
Keyword(s):  
Fluid Model ◽  
Larmor Radius ◽  
Finite Larmor Radius ◽  
Acoustic Modes ◽  
Two Fluid Model ◽  
Two Fluid
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