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We show that a simple, modified version of the Magnetorotational Instability (MRI) can develop in the outer liquid core of the Earth, in the presence of a background shear. It requires either thermal wind, or a primary instability, such as…

Earth and Planetary Astrophysics · Physics 2015-05-13 Ludovic Petitdemange , Emmanuel Dormy , Steven A. Balbus

Gravity modes are the best probes to study the solar radiative zone dynamics, especially in the nuclear core. These modes remain difficult to observe, but they are essential ingredients for progressing on the evolution of the Sun-Earth…

Astrophysics · Physics 2009-11-11 Sylvaine Turck-Chieze

Earth-like planets have anelastic mantles, whereas giant planets may have anelastic cores. As for the fluid parts of a body, the tidal dissipation of such solid regions, gravitationally perturbed by a companion body, highly depends on its…

Earth and Planetary Astrophysics · Physics 2012-08-03 F. Remus , S. Mathis , J. -P. Zahn , V. Lainey

We invert for motions at the surface of Earth's core under spatial and temporal constraints that depart from the mathematical smoothings usually employed to ensure spectral convergence of the flow solutions. Our spatial constraints are…

Geophysics · Physics 2023-12-18 Olivier Barrois , Nicolas Gillet , Julien Aubert

Some results are presented of the Earth's microseismic background. It is assumed that background peaks should correspond to the resonance gravity-wave exchange in the system of two gravity-connected bodies. The microseismic spectrum is…

Astrophysics · Physics 2007-05-23 V. A. Dubrovskiy

Asteroseismology has been used extensively in recent years to study the interior structure and physical processes of main sequence stars. We consider prospects for using pressure modes (p-modes) near the frequency of maximum oscillation…

Solar and Stellar Astrophysics · Physics 2023-06-14 Christopher J. Lindsay , J. M. Joel Ong , Sarbani Basu

The problem of the turbulent thermal convection in the Earth's liquid core is considered. Following assumptions on decreasing of the spatial scales due to the rapid rotation, we propose the subgrid model of the eddy diffusivity, which is…

Fluid Dynamics · Physics 2007-05-23 M. Reshetnyak , B. Steffen

The shrinking core model describes the reaction of a spherical solid particle with a surrounding fluid. In this work, we revisit the SCM by deriving it from the underlying physical processes and performing a careful non-dimensionalisation,…

Other Condensed Matter · Physics 2025-08-05 Cristian Moreno-Pulido , Rachael Olwande , Tim Myers , Francesc Font

There are different kinds of intensity measures to characterize the main properties of the earthquake records. This paper proposes a simulation-based approach to compute correlation coefficients of motion duration and intensity measures of…

Geophysics · Physics 2020-06-09 Mojtaba Harati , Mohammadreza Mashayekhi , Homayoon E. Estekanchi

Cosmological constant problem (in its various versions) is arguably the deepest gap in our understanding of theoretical physics, the solution to which may very likely require revisiting the Einstein theory of gravity. In this letter, I…

Astrophysics · Physics 2008-07-18 Niayesh Afshordi

The electroseismic model describes the coupling phenomenon of the electromagnetic waves and seismic waves in fluid immersed porous rock. Electric parameters have better contrast than elastic parameters while seismic waves provide better…

Analysis of PDEs · Mathematics 2019-03-27 Eric Bonnetier , Faouzi Triki , Qi Xue

Central stars of extra-solar planetary systems are metal-rich. Planet accretion or initial surmetallicity can explain this observationnal fact. These scenarios can be tested with asteroseismology. We calibrate two stellar models, one with…

Astrophysics · Physics 2007-05-23 Michael Bazot , Sylvie Vauclair

The asymmetric molecular emission lines from dense cores reveal slow, inward motion in the clouds' outer regions. This motion is present both before and after the formation of a central star. Motivated by these observations, we revisit the…

Solar and Stellar Astrophysics · Physics 2015-06-05 Paul A. Dalba , Steven W. Stahler

We perform direct numerical simulations of the tidal encounter of a rotating planet on a highly eccentric or parabolic orbit about a central star formulated as an initial value problem. This approach enables us to extend previous work of…

Solar and Stellar Astrophysics · Physics 2015-05-19 J. C. B. Papaloizou , P. B. Ivanov

Ground observatory and satellite-based determinations of temporal variations in the geomagnetic field probe a decadal to annual time scale range where Earth's core slow, inertialess convective motions and rapidly propagating,…

Geophysics · Physics 2021-02-15 Julien Aubert , Nicolas Gillet

We present the results of 3--D simulations of core convection within A-type stars of 2 solar masses, at a range of rotation rates. We consider the inner 30% by radius of such stars, thereby encompassing the convective core and some of the…

Astrophysics · Physics 2008-11-26 Matthew Browning , Allan Sacha Brun , Juri Toomre

We derive knowledge on the global and structural parameters of low-mass stars using asteroseismology and taking advantage of the stellar collective behavior within open clusters. We build stellar models and compute the seismic signal…

Astrophysics · Physics 2008-11-26 L. Piau , J. Ballot , S. Turck-Chieze

An important and long-standing puzzle in the history of modern physics is the gross inconsistency between theoretical expectations and cosmological observations of the vacuum energy density, by at least 60 orders of magnitude, otherwise…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-25 Ali Narimani , Niayesh Afshordi , Douglas Scott

Seismic waves sensitive to the outermost part of the Earth's liquid core seem to be affected by a stably stratified layer at the core-mantle boundary. Such a layer could have an observable signature in both long-term and short-term…

Geophysics · Physics 2015-06-29 Jérémie Vidal , Nathanaël Schaeffer

In helioseismology, there is a well-known offset between observed and computed oscillation frequencies. This offset is known to arise from improper modeling of the near-surface layers of the Sun, and a similar effect must occur for models…

Astrophysics · Physics 2009-11-13 Hans Kjeldsen , Timothy R. Bedding , Joergen Christensen-Dalsgaard