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We discuss wave propagation in rotating superfluid neutron star cores, taking into account the vortex mediated mutual friction force. For models where the two fluids co-rotate in the unperturbed state, our analysis clarifies the role of…

Astrophysics · Physics 2009-11-13 T. Sidery , N. Andersson , G. L. Comer

Motivated by recent observational searches of sub-structure in starless molecular cloud cores, we investigate the evolution of density perturbations on scales smaller than the Jeans length embedded in contracting isothermal clouds, adopting…

Solar and Stellar Astrophysics · Physics 2017-12-20 C. Toci , D. Galli , A. Verdini , L. Del Zanna , S. Landi

We present results from a suite of three-dimensional global hydrodynamic simulations which show that spiral density waves propagating in circumstellar disks are unstable to the growth of a parametric instability that leads to break-down of…

Earth and Planetary Astrophysics · Physics 2016-09-21 Jaehan Bae , Richard P. Nelson , Lee Hartmann , Samuel Richard

We show that grains streaming through a fluid are generically unstable if their velocity, projected along some direction, matches the phase velocity of a fluid wave (linear oscillation). This can occur whenever grains stream faster than any…

Earth and Planetary Astrophysics · Physics 2018-04-11 Jonathan Squire , Philip F. Hopkins

We study modulational stability and instability in the Whitham equation, combining the dispersion relation of water waves and a nonlinearity of the shallow water equations, and modified to permit the effects of surface tension and constant…

Analysis of PDEs · Mathematics 2015-08-28 Vera Mikyoung Hur , Mathew A. Johnson

A new condition for the linear dissipative instability of the strong plane shock wave in an arbitrary medium is obtained. The instability of the shock is realized due to the flow instability behind its front, which is similar to the known…

Fluid Dynamics · Physics 2020-06-24 Sergey G. Chefranov

Jeans instability is analysed in an expanding universe within the framework of BGK model of the Boltzmann equation and Poisson equations. The background is characterized by a comoving Maxwellian distribution function and a space-time…

General Relativity and Quantum Cosmology · Physics 2022-06-01 Gilberto M. Kremer

We investigate the linear stability of a flat interface that separates a liquid layer from a fully-developed turbulent gas flow. In this context, linear-stability analysis involves the study of the dynamics of a small-amplitude wave on the…

Fluid Dynamics · Physics 2009-08-13 L. Ó Náraigh , P. Spelt , O. Matar , T. Zaki

By employing a local two-fluid theory, we investigate an obliquely propagating electromagnetic instability in the lower hybrid frequency range driven by cross-field current or relative drifts between electrons and ions. The theory…

Astrophysics · Physics 2007-05-23 Hantao Ji , Russell Kulsrud , William Fox , Masaaki Yamada

Since the early 1990s, there has been significant interest in the physics of dusty plasmas, which has now become a new discipline in plasma science. Dusty plasma exhibits new and unusual behaviour, and provides a possibility for modified or…

General Relativity and Quantum Cosmology · Physics 2026-05-19 Tanay Gupta , Isha Shailesh , Ram Prasad Prajapati

When two plasmas collide, their interaction can be mediated by collisionless plasma instabilities or binary collisions between particles of each shell. By comparing the maximum growth rate of the collisionless instabilities with the…

Plasma Physics · Physics 2018-07-18 Antoine Bret , Asaf Pe'er

The well known Jeans instability is studied for a viscoelastic, gravitational fluid using generalized hydrodynamic equations of motions. It is found that the threshold for the onset of instability appears at higher wavelengths in a…

Solar and Stellar Astrophysics · Physics 2015-06-17 M. S. Janaki , N. Chakrabarti , D. Banerjee

We consider the stability of periodic gravity free-surface water waves traveling downstream at a constant speed over a shear flow of finite depth. In case the free surface is flat, a sharp criterion of linear instability is established for…

Analysis of PDEs · Mathematics 2007-11-28 Vera Mikyoung Hur , Zhiwu Lin

Laminar-turbulent pattern formation is a distinctive feature of the intermittency regime in subcritical plane shear flows. By performing extensive numerical simulations of the plane channel flow, we show that the pattern emerges from a…

Fluid Dynamics · Physics 2022-12-16 Pavan V. Kashyap , Yohann Duguet , Olivier Dauchot

Flow instabilities play important roles in a wide range of engineering, geophysical, and astrophysical flows, ranging from supernova explosion in crab nebula, formation of clouds in sky, waves on ocean, to inertial confinement fusion…

Fluid Dynamics · Physics 2024-06-06 Wei Li

The propagation of unstable interfaces is at the origin of remarkable patterns that are observed in various areas of science as chemical reactions, phase transitions, growth of bacterial colonies. Since a scalar equation generates usually…

Analysis of PDEs · Mathematics 2014-01-31 Michal Kolwalczyk , Benoit Perthame , Nicolas Vauchelet

Spatial intermittency in decaying kinetic Alfven wave turbulence is investigated to determine if it produces non Gaussian density fluctuations in the interstellar medium. Non Gaussian density fluctuations have been inferred from pulsar…

Astrophysics · Physics 2011-02-11 P. W. Terry , K. W. Smith

An analysis of MHD wave propagating in a gravitating and rotating medium permeated by non-uniform magnetic field has been done. It has been found that the Gradient of Magnetic Field when coupled with Rotation becomes capable to generate few…

Astrophysics · Physics 2008-05-29 Ipsita Das , Ramaprosad Bondyopadhaya

Particles in pressure-driven channel flow are often inhomogeneously distributed. Two modes of low-Reynolds number instability, absent in Poiseuille flow of clean fluid, are created by inhomogeneous particle loading, and their mechanism is…

Fluid Dynamics · Physics 2024-11-27 Anup Kumar , Rama Govindarajan

We consider the linear stability of shear banded planar Couette flow of the Johnson-Segalman fluid, with and without the addition of stress diffusion to regularise the equations. In particular, we investigate the effect of two-dimensional…

Soft Condensed Matter · Physics 2007-06-13 H. J. Wilson , S. M. Fielding