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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

We demonstrate a universal mechanism of a class of instabilities in infrared regions for massless Abelian $p$-form gauge theories with topological interactions, which we call generalized chiral instabilities. Such instabilities occur in the…

High Energy Physics - Theory · Physics 2023-07-13 Naoki Yamamoto , Ryo Yokokura

We study nonaxisymmetric perturbations of rotating relativistic stars. modeled as perfect-fluid equilibria. Instability to a mode with angular dependence $\exp(im\phi)$ sets in when the frequency of the mode vanishes. The locations of these…

General Relativity and Quantum Cosmology · Physics 2009-10-30 Nikolaos Stergioulas , John L. Friedman

In this paper we provide sharp criteria for linear stability or instability of equilibria of collisionless plasmas in the presence of boundaries. Specifically, we consider the relativistic Vlasov-Maxwell system with specular reflection at…

Analysis of PDEs · Mathematics 2011-12-21 Toan Nguyen , Walter A. Strauss

The effect of the Hall term on the evolution of the magnetorotational instability (MRI) in weakly ionized accretion disks is investigated using local axisymmetric simulations. First, we show that the Hall term has important effects on the…

Astrophysics · Physics 2009-11-07 Takayoshi Sano , James M. Stone

Hollerbach and Rudiger have reported a new type of magnetorotational instability (MRI) in magnetized Taylor-Couette flow in the presence of combined axial and azimuthal magnetic fields. The salient advantage of this "helical'' MRI (HMRI) is…

Astrophysics · Physics 2008-11-26 Wei Liu , Jeremy Goodman , Isom Herron , Hantao Ji

We consider a differentially rotating flow of an incompressible electrically conducting and viscous fluid subject to an external axial magnetic field and to an azimuthal magnetic field that is allowed to be generated by a combination of an…

Fluid Dynamics · Physics 2021-11-01 Rong Zou , Joris Labarbe , Yasuhide Fukumoto , Oleg N. Kirillov

We show by means of a perturbative weakly nonlinear analysis that the axisymmetric magnetorotational instability (MRI) of a viscous, resistive, incompressible rotating shear flow in a thin channel gives rise to a real Ginzburg-Landau…

Astrophysics · Physics 2008-11-26 O. M. Umurhan , K. Menou , O. Regev

The effects of ambipolar diffusion on the linear stability of weakly ionised accretion discs are examined. Earlier work on this topic has focused on axial magnetic fields and perturbation wavenumbers. We consider here more general field and…

Astrophysics · Physics 2009-11-10 Matthew W. Kunz , Steven A. Balbus

The saturation mechanism of Magneto-Rotational Instability (MRI) is examined through analytical quasilinear theory and through nonlinear computation of a single mode in a rotating disk. We find that large-scale magnetic field is generated…

High Energy Astrophysical Phenomena · Physics 2011-02-11 F. Ebrahimi , S. C. Prager , D. D. Schnack

We venture for the comparison between growth rates for magnetorotational instability (MRI) and hydrodynamics instability in the presence of an extra force in the local Keplerian accretion flow. The underlying model is described by the…

High Energy Astrophysical Phenomena · Physics 2022-05-27 Subham Ghosh , Banibrata Mukhopadhyay

An asymptotic model based on a reductive perturbative expansion of the drift kinetic and the Maxwell equations is used to demonstrate that, near the instability threshold, the nonlinear dynamics of mirror modes in a magnetized plasma with…

Plasma Physics · Physics 2015-05-13 E. A. Kuznetsov , T. Passot , P. L. Sulem

We investigate the global stability of a differentially rotating fluid shell threaded by vertical and azimuthal magnetic fields to linear, axisymmetric perturbations. This system, which models a thick accretion disk in the vicinity of its…

Astrophysics · Physics 2009-10-28 Charles Curry , Ralph E. Pudritz

Magnetohydrodynamic (MHD) instabilities can play an important role in the structure and dynamics of the pulsar magnetosphere. We consider the instabilitycaused by differential rotation that is suggested by many theoretical models. Stability…

High Energy Astrophysical Phenomena · Physics 2015-06-04 V. Urpin

The stability of nonaxisymmetric perturbations in differentially rotating astrophysical accretion disks is analyzed by fully incorporating the properties of shear flows. We verify the presence of discrete unstable eigenmodes with complex…

Astrophysics · Physics 2009-10-31 K. Noguchi , T. Tajima , R. Matsumoto

In this paper, we develop the analysis of a two-dimensional magnetohydrodynamical configuration for an axially symmetric and rotating plasma (embedded in a dipole like magnetic field), modeling the structure of a thin accretion disk around…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Giovanni Montani , Riccardo Benini

The effect of magnetic field diffusion on the stability of accretion disks is a problem that has attracted considerable interest of late. In particular, the Hall effect has the potential to bring about remarkable changes in the dynamical…

Earth and Planetary Astrophysics · Physics 2017-03-29 Gopakumar Mohandas , Martin E. Pessah

Axisymmetric equilibria with incompressible flows of arbitrary direction are studied in the framework of magnetohydrodynamics under a variety of physically relevant side conditions. To this end a set of pertinent non-linear ODEs are…

Plasma Physics · Physics 2007-05-23 G. N. Throumoulopoulos , H. Tasso , G. Poulipoulis

We solve the linearized gyrokinetic equation, quasineutrality condition, and Ampere's law to obtain the dispersion relation of microtearing modes (MTMs) in collisionless low-beta toroidal plasmas. Consistent with past studies, we find that…

Plasma Physics · Physics 2024-02-28 Benjamin D. G. Chandran , Alexander A. Schekochihin

We derive the conductivity tensor for axisymmetric perturbations of a hot, collisionless, and charge-neutral plasma in the shearing sheet approximation. Our results generalize the well-known linear Vlasov theory for uniform plasmas to…

High Energy Astrophysical Phenomena · Physics 2015-01-06 Tobias Heinemann , Eliot Quataert