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Related papers: Scalar Perturbations in Two-Temperature Cosmologic…

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The influence of motion of ions and electron temperature on nonlinear one-dimensional plasma waves with velocity close to the speed of light in vacuum is investigated. It is shown that although the wavebreaking field weakly depends on mass…

Plasma Physics · Physics 2009-10-31 Arsen G. Khachatryan

A mathematical model of the evolution of plane perturbations in the cosmological statistical system of completely degenerate scalar-charged fermions with Higgs scalar interaction for short-wave perturbations is formulated. These disturbance…

General Relativity and Quantum Cosmology · Physics 2021-03-26 Yu. G. Ignat'ev

We study the dynamics of cosmological perturbations in models of dark matter based on ultralight coherent vector fields. Very much as for scalar field dark matter, we find two different regimes in the evolution: for modes with $k^2\ll {\cal…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-08 J. A. R. Cembranos , A. L. Maroto , S. J. Núñez Jareño

We consider the linear perturbations for the single scalar field inflation model interacting with an additional triad of scalar fields. The background solutions of the three additional scalar fields depend on spatial coordinates with a…

General Relativity and Quantum Cosmology · Physics 2013-09-04 Seoktae Koh , Seyen Kouwn , O-Kab Kwon , Phillial Oh

A generalized plasma model having warm ions, iso-thermal electrons, super-thermal electrons and positrons is considered to theoretically investigate the modulational instability (MI) of ion-acoustic waves (IAWs). A standard nonlinear…

Plasma Physics · Physics 2020-06-04 S. Banik , N. M. Heera , T. Yeashna , M. R. Hassan , R. K. Shikha , N. A. Chowdhury , A. Mannan , A. A. Mamun

We present a framework to describe completely general first-order perturbations of static, spatially compact, and locally rotationally symmetric class II spacetimes within the theory of general relativity. The perturbation variables are by…

General Relativity and Quantum Cosmology · Physics 2024-05-10 Paulo Luz , Sante Carloni

Using a perturbative approach, an evolution equation for the space charge density, correct up to the third order, is deduced for arbitrary initial density profiles of the electron and ion fluids in a cold nonrelativistic plasma. The…

Plasma Physics · Physics 2024-10-10 Subhasish Bag , Vikrant Saxena

We study the local gravitational instability of non-rotating astrophysical fluids allowing for the presence of an external gravitational potential in addition to the fluid self-gravity. We present a self-consistent linear-perturbation…

Astrophysics of Galaxies · Physics 2026-02-18 Carlo Nipoti

A photoionized gas in thermal equilibrium can display a thermal instability, with 3 or more solutions in the multi-branch region of the S-shape curve giving the temperature versus the radiation-to-gas-pressure ratio. Many studies have been…

Astrophysics · Physics 2009-11-11 A. C. Goncalves , S. Collin , A. -M. Dumont , L. Chevallier

Kinetic instabilities in weakly collisional, high beta plasmas are investigated using two-dimensional hybrid expanding box simulations with Coulomb collisions modeled through the Langevin equation (corresponding to the Fokker-Planck one).…

Plasma Physics · Physics 2019-02-20 Petr Hellinger , Pavel M. Travnicek

This paper explores the hybridization of linear metric perturbations with linear electromagnetic (EM) perturbations in non-magnetized plasma for a general background metric. The local wave properties are derived from first principles for…

General Relativity and Quantum Cosmology · Physics 2025-06-03 Deepen Garg , I. Y. Dodin

Small non-spherical perturbations of a spherically symmetric but time-dependent background spacetime can be used to model situations of astrophysical interest, for example the production of gravitational waves in a supernova explosion. We…

General Relativity and Quantum Cosmology · Physics 2009-10-31 C. Gundlach , J. M. Martin-Garcia

The model under consideration is a two-dimensional two-component plasma, stable against collapse for the dimensionless coupling constant $\beta<2$. The combination of a technique of renormalized Mayer expansion with the mapping onto the…

Statistical Mechanics · Physics 2007-05-23 L. Šamaj , I. Travěnec

The relaxation of temperatures and velocities of the components of a quasi-equilibrium two-component homogeneous completely ionized plasma is investigated on the basis of a generalization of the Chapman-Enskog method applied to the Landau…

Statistical Mechanics · Physics 2015-10-23 V. N. Gorev , A. I. Sokolovsky , Z. Yu. Chelbaevsky

We investigate the growth of ion density perturbations in large-amplitude linear laser wakefields via two-dimensional particle-in-cell simulations. Growth rates and wave numbers are found to be consistent with a longitudinal strong-field…

Plasma Physics · Physics 2023-03-22 Alexander von Boetticher , Roman Walczak , Simon Hooker

We consider density fluctuations of a two-fluid model consisting of hydrogen plasma and radiation prior to the cosmic hydrogen recombination. As investigation method that of the dispersion relations is applied, which have been derived from…

Astrophysics · Physics 2009-11-07 Eva Gessner , Heinz Dehnen

There is renewed interest in direct-drive inertial confinement fusion, following the milestone December 2022 3.15 MJ ignition result on the National Ignition Facility. A key obstacle is the control of the two plasmon decay instability.…

We present a new, fully covariant and manifestly gauge-invariant expression for the temperature anisotropy in the cosmic microwave background radiation resulting from scalar perturbations. We pay particular attention to gauge issues such as…

Astrophysics · Physics 2009-12-30 A. D. Challinor , A. N. Lasenby

The dynamical evolution of hot optically thin plasmas in the ISM crucially depends on the heating and cooling processes. It is essential to realize that all physical processes that contribute operate on different time scales. In particular…

Astrophysics · Physics 2009-11-07 Dieter Breitschwerdt

In this letter we review the separate universe approach for cosmological perturbations and point out that it is essentially the lowest order approximation to a gradient expansion. Using this approach, one can study the nonlinear evolution…

Astrophysics · Physics 2009-11-10 G. I. Rigopoulos , E. P. S. Shellard