Mathematical modeling of a mushy layer at the inner core boundary of the Earth. Part 2. Theoretical description

2015 ◽  
Author(s):  
D. V. Alexandrov ◽  
A. P. Malygin ◽  
I. V. Alexandrova
Keyword(s):  
Mathematical Modeling ◽  
Inner Core ◽  
Theoretical Description ◽  
Mushy Layer ◽  
The Earth ◽  
Core Boundary

A study of conditions at the inner core boundary of the earth

1981 ◽  
Vol 24 (4) ◽  
pp. 302-307 ◽  
Author(s):  
David E. Loper ◽  
Paul H. Roberts
Keyword(s):  
Inner Core ◽  
The Earth ◽  
Core Boundary

scholarly journals On shear wave velocity in the top of the Earth’s inner core

2019 ◽  
Vol 488 (4) ◽  
pp. 434-438
Author(s):  
D. N. Krasnoshchekov ◽  
V. M. Ovtchinnikov ◽  
O. A. Usoltseva
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Inner Core ◽  
Solid Core ◽  
The Earth ◽  
Inner Surface ◽  
Core Boundary ◽  
Standard Models ◽  
Earth’S Inner Core

Analysis of PKIIKP waves reflected off the inner surface of the solid core boundary and recorded close to the antipode indicates the shear wave velocity in its top can be by 10-60% below 3.5 km/s envisaged by standard models of the Earth.

scholarly journals Solved and unsolved questions in the non-rigid Earth nutation study

2007 ◽  
Vol 3 (S248) ◽  
pp. 374-378
Author(s):  
C. L. Huang
Keyword(s):  
Inner Core ◽  
Outer Core ◽  
Earth Model ◽  
Future Studies ◽  
Atmospheric Loading ◽  
The Earth ◽  
Core Boundary ◽  
Oceanic Tides ◽  
Rigid Earth ◽  
Electro Magnetic

AbstractAt the IAU 26th GA held in Prague in 2006, a new precession model (P03) was recommended and adopted to replace the old one, IAU1976 precession model. This new P03 model is to match the IAU2000 nutation model that is for anelastic Earth model and was adopted in 2003 to replace the previous IAU1980 model. However, this IAU2000 nutation model is also not a perfect one for our complex Earth, as stated in the resolution of IAU nutation working group. The Earth models in the current nutation theories are idealized and too simple, far from the real one. They suffer from several geophysical factors: the an-elasticity of the mantle, the atmospheric loading and wind, the oceanic loading and current, the atmospheric and oceanic tides, the (lateral) heterogeneity of the mantle, the differential rotation between the inner core and the mantle, and various couplings between the fluid outer core and its neighboring solids (mantle and inner core). In this paper, first we give a very brief review of the current theoretical studies of non-rigid Earth nutation, and then focus on the couplings near the core-mantle boundary and the inner core-outer core boundary, including the electro-magnetic, viscous, topographic, and gravitational couplings. Finally, we outline some interesting future studies.

scholarly journals On the existence and structure of a mush at the inner core boundary of the Earth

2007 ◽  
Vol 164 (1-2) ◽  
pp. 36-49 ◽  
Author(s):  
R. Deguen ◽  
T. Alboussière ◽  
D. Brito
Keyword(s):  
Inner Core ◽  
The Earth ◽  
Core Boundary

scholarly journals Gravitational, Inertial and Toroidal Oscillations of the Outer Core and Their Related Free Wobbles

1980 ◽  
Vol 78 ◽  
pp. 185-186
Author(s):  
Po-Yu Shen
Keyword(s):  
Inner Core ◽  
Numerical Solutions ◽  
Outer Core ◽  
Angular Frequency ◽  
Inertial Oscillations ◽  
The Earth ◽  
Core Boundary ◽  
Restoring Forces ◽  
Rotation Of The Earth ◽  
Core Modes

According to the respective restoring forces of self-gravitation, Coriolis force, and inertial coupling at the boundaries, the free oscillations of a contained fluid can be classified into gravitational, inertial, and toroidal oscillations. For the outer core of the Earth, however, due to the interplay of rotation, elasticity, and self-gravitation, the gravitational undertones and inertial oscillations are not distinguishable. Both have eigenfunctions consisting of spheroidal and toroidal parts of about equal amplitude, and exist in alternating allowed and forbidden zones depending on the gravitational stability of the outer core. The forbidden zones for a stable core correspond to the allowed zones for an unstable core, while for a neutrally stratified core there appear to be no forbidden zones. The eigenfunction of a toroidal mode consists essentially of a primary toroidal field and a secondary spheroidal component of the order of ellipticity, coupled at the outer core-mantle or outer core-inner core boundary. Therefore, in general, toroidal core modes appear in doublets Sn+1m Tnm and Sn−1m Tn−1m with degenerate frequency equal to 2m/n(n+1) times the angular frequency of rotation of the Earth. The ellipticities of the outer core boundaries are responsible for the removal of the degeneracy. It is shown that the primary toroidal and secondary spheroidal fields constitute the “generalized Poincare motion” which, for the fundamental mode S21T11, reduces to the “simple motion” defined by Poincare in 1910. Numerical solutions have been obtained for all three types of free core modes. While those for gravitational undertones and inertial oscillations are obtained by arbitrarily truncating the hydrodynamic equations, it is shown that the eigensolutions for toroidal modes are correct to first order in ellipticity due to the particular geometry of the outer core of the Earth.

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